Bio


A native of the Bay Area, Dr. Raja Narayan attended James Logan High School in Union City before going to Berkeley to obtain his BS in Chemical Biology, Yale for his MPH in Biostatistics, and the University of California Irvine for his MD. Dr. Narayan joined the Stanford General Surgery residency program in 2015.

Before joining Stanford, Dr. Narayan developed a library of physiology and clinical education videos for the popular online learning platform, Khan Academy, where his videos have been viewed over 20 million times in all 7 continents. His work in education technology earned him the New England Journal of Medicine Gold Scholar award. While a graduate student at Yale, Dr. Narayan led a multi-disciplinary team of engineers, pathologists, and surgeons to design, construct, test, and patent a device to preserve intestinal tissue for small bowel transplantation and drug testing. This work earned him grants from the Yale Center for Engineering, Innovation, and Design as well as the Physicians of Tomorrow and Excellence in Medicine awards from the American Medical Association. As a medical student, Dr. Narayan was elected to the Αlpha Omega Αlpha Honor Society where he served as President of the Zeta chapter in 2014 and is serving as Research Chair of the Stanford chapter from 2019-2022.

Between 2017-2019, Dr. Narayan was a research fellow with the Hepatopancreatobiliary Surgery service at the Memorial Sloan Kettering Cancer Center studying targets for pancreatic cancer vaccines, genomic markers of liver tumor biology, and regional differences in biliary tree cancer arising in patients from around the world. Since returning to Stanford in June 2019, Dr. Narayan now leads a team studying the use of artificial intelligence to define liver histopathology to predict clinical outcomes. This work has received institutional as well as national funding and acclaim including the Young Investigator Award from the American Transplant Congress and the Postgraduate Fellowship Award from the Αlpha Omega Αlpha Honor Society.

After completion of his residency training, Dr. Narayan will pursue fellowship training in Complex General Surgical Oncology at Harvard at the Massachusetts General Hospital, Brigham & Women’s Hospital, and the Dana-Farber Cancer Institute.

Clinical Focus


  • Residency
  • General Surgery
  • Hepatobiliary and Pancreatic Surgery
  • Surgical Oncology

Honors & Awards


  • Best Clinical Research Oral Presentation, Stanford University Department of Surgery (2020)
  • Postgraduate Fellowship Award, Αlpha Omega Αlpha Honor Society (2020)
  • Young Investigator Award, American Transplant Congress (2020)
  • Best Clinical Research Oral Presentation, Stanford University Department of Surgery (2019)
  • Presidential Plenary Finalist, Americas Hepato-Pancreato-Biliary Association (2018)
  • Excellence in Medicine Award, American Medical Association (2014)
  • Global Health Case Competition 1st Place, Yale Global Health Leadership Initiative (2014)
  • Physicians of Tomorrow Award, American Medical Association (2014)
  • Gold Scholar Award, New England Journal of Medicine (2012)

Boards, Advisory Committees, Professional Organizations


  • Resident and Associate Society Reviewer, Journal of the American College of Surgeons (2020 - Present)
  • Editorial Board Member, Translational Gastroenterology and Hepatology (2020 - Present)
  • Resident Editorial Board Member, Journal of Gastrointestinal Surgery (2019 - Present)
  • Resident Selection Committee Member, Stanford University General Surgery Residency Training Program (2020 - Present)
  • Program Evaluation Committee Member, Stanford University General Surgery Residency Training Program (2019 - Present)
  • Research Chair, Alpha Omega Alpha Honor Society (2019 - Present)
  • Medical Content Creator, Khan Academy (2013 - 2015)
  • Institutional Review Board Member, Yale University School of Medicine (2013 - 2014)

Professional Education


  • Clinical Fellowship, Harvard (Mass General Brigham), Complex General Surgical Oncology (2024)
  • Residency, Stanford University, General Surgery (2022)
  • Postdoctoral Fellowship, Memorial Sloan Kettering Cancer Center, Hepatopancreatobiliary Surgery (2019)
  • MD, University of California, Irvine, Medicine (2015)
  • MPH, Yale School of Public Health, Applied Biostatistics and Epidemiology (2014)
  • BS, University of California, Berkeley, Chemical Biology (2009)

Patents


  • Marc L. Melcher, Linfeng Yang, Raja R. Narayan, Simon B. Chen, Natasha Abadilla. "United States Patent 17/075535 Quantification of Liver Steatosis from a biopsy using a Computer Imaging Platform", Leland Stanford Junior University, Apr 29, 2021
  • John P. Geibel, Joseph Zinter, Manuel Rodriguez-Davalos, Roger Patron-Lozano, Spencer Backus, Andrew Crouch, Brian Loeb, Raja Narayan, Kristi Oki, Natalie Pancer,. "United States Patent 14/674,678 Perfusion systems and methods of perfusing at least a portion of a small intestine", Yale University, Mar 10, 2016

Personal Interests


Surgical Oncology, Hepatopancreatobiliary (HPB) Surgery, Hepatic Artery Infusion Chemotherapy, Tumor Genome, Cancer Immunotherapy, Artificial Intelligence, Gastric Cancer, Cancer Outcomes

All Publications


  • Association of genomic profiles and survival in early onset and screening-age colorectal cancer patients with liver metastases resected over 15 years. Journal of surgical oncology Narayan, R. R., Aveson, V. G., Chou, J. F., Walch, H. S., Sanchez-Vega, F., Santos Fernandes, G. D., Balachandran, V. P., D'Angelica, M. I., Drebin, J. A., Jarnagin, W. R., Wei, A. C., Cercek, A., Gonen, M., Schultz, N., Kingham, T. P. 1800

    Abstract

    BACKGROUND: This study explores whether genomic profiles of colorectal liver metastasis (CRLM) patients with early onset (EO,<50 years old) and screening age (SA) primary diagnosis are associated with overall survival (OS).METHODS: All patients undergoing hepatectomy between 2002 and 2017 were identified and tumor specimens with next-generation sequencing data were cataloged. Gene and signaling-level alterations were checked for association with OS from primary diagnosis accommodating for left-truncated survival.RESULTS: Of 1822 patients, 333 were sequenced-127 (38%) EO-CRLM and 206 (62%) SA-CRLM patients. More aggressive features presented in EO-CRLM patients-synchronous metastatic presentation (83% vs. 75%, p<0.001) and primary node-positive disease (71% vs. 61%, p<0.001). The median OS from primary diagnosis was 11.8 years (95% confidence interval=7.94-NA). Five-year OS did not differ by age (p=0.702). On multivariable analysis, altered APC (EO-CRLM: [hazard ratio [HR]=0.37, p=0.018] vs. SA-CRLM:[HR=0.61, p=0.260]), BRAF (EO-CRLM:[HR=4.38, p=0.007] vs. SA-CRLM:[HR=4.78, p=0.032]), and RAS-TP53 (EO-CRLM:[HR=2.82, p=0.011] vs. SA-CRLM:[HR=2.35, p=0.003]) associated with OS.CONCLUSIONS: Despite bearing more aggressive features, EO-CRLM patients had similar genomic profiles and survival as SA-CRLM patients. Better performance status in younger patients leading to increased treatment tolerance may partly explain this. As screening and treatment strategies from older patients are applied to younger patients, genomic predictors of biology identified historically in older cohorts could apply to EO patients.

    View details for DOI 10.1002/jso.26797

    View details for PubMedID 35066881

  • Advances in the surgical management of gastric and gastroesophageal junction cancer. Translational gastroenterology and hepatology Narayan, R. R., Poultsides, G. A. 2021; 6: 16

    Abstract

    Since Theodore Billroth and Cesar Roux perfected the methods of post-gastrectomy reconstruction in the late 19th century, surgical management of gastric and gastroesophageal cancer has made incremental progress. The majority of patients with localized disease are treated with perioperative combination chemotherapy or neoadjuvant chemoradiation. Staging laparoscopy before initiation of treatment or before surgical resection has improved staging accuracy and can drastically inform treatment decisions. The longstanding and contentious debate on the optimal extent of lymph node dissection for gastric cancer appears to have settled in favor of D2 dissection with the recently published 15-year follow-up of the Dutch randomized trial. Minimally invasive gastric and gastroesophageal resections are performed routinely in most centers affording faster recovery and equivalent oncologic outcomes. Pylorus-preserving distal (central) gastrectomy has emerged as a less invasive, function-preserving option for T1N0 middle-third gastric cancers, while randomized data on its oncologic adequacy are pending. Multi-visceral resections and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy has been utilized selectively for patients with locally advanced tumors who have demonstrated disease control on preoperative chemotherapy. This review summarizes the current standard of surgical care for gastroesophageal junction and gastric cancer as well as highlights recent and upcoming advances to the field.

    View details for DOI 10.21037/tgh.2020.02.06

    View details for PubMedID 33409410

    View details for PubMedCentralID PMC7724174

  • Artificial intelligence for prediction of donor liver allograft steatosis and early post-transplantation graft failure. HPB : the official journal of the International Hepato Pancreato Biliary Association Narayan, R. R., Abadilla, N., Yang, L., Chen, S. B., Klinkachorn, M., Eddington, H. S., Trickey, A. W., Higgins, J. P., Melcher, M. L. 2021

    Abstract

    Donor livers undergo subjective pathologist review of steatosis before transplantation to mitigate the risk for early allograft dysfunction (EAD). We developed an objective, computer vision artificial intelligence (CVAI) platform to score donor liver steatosis and compared its capability for predicting EAD against pathologist steatosis scores.Two pathologists scored digitized donor liver biopsy slides from 2014 to 2019. We trained four CVAI platforms with 1:99 training:prediction split. Mean intersection-over-union (IU) characterized CVAI model accuracy. We defined EAD using liver function tests within 1 week of transplantation. We calculated separate EAD logistic regression models with CVAI and pathologist steatosis and compared the models' discrimination and internal calibration.From 90 liver biopsies, 25,494 images trained CVAI models yielding peak mean IU = 0.80. CVAI steatosis scores were lower than pathologist scores (median 3% vs 20%, P < 0.001). Among 41 transplanted grafts, 46% developed EAD. The median CVAI steatosis score was higher for those with EAD (2.9% vs 1.9%, P = 0.02). CVAI steatosis was independently associated with EAD after adjusting for donor age, donor diabetes, and MELD score (aOR = 1.34, 95%CI = 1.03-1.75, P = 0.03).The CVAI steatosis EAD model demonstrated slightly better calibration than pathologist steatosis, meriting further investigation into which modality most accurately and reliably predicts post-transplantation outcomes.

    View details for DOI 10.1016/j.hpb.2021.10.004

    View details for PubMedID 34815187

  • Addition of adjuvant hepatic artery infusion to systemic chemotherapy following resection of colorectal liver metastases is associated with reduced liver-related mortality. Journal of surgical oncology Srouji, R., Narayan, R., Boerner, T., Buisman, F., Seier, K., Gonen, M., Balachandran, V. P., Drebin, J., Jarnagin, W. R., Kingham, T. P., Wei, A., Kemeny, N. E., D'Angelica, M. 2020

    Abstract

    BACKGROUND: After resection of colorectal liver metastases (CRLM), recurrent disease in the liver is a major cause of death but may be reduced with the addition of adjuvant hepatic arterial infusion (HAI) chemotherapy to systemic chemotherapy (SYS).OBJECTIVE: This study investigates organ-specific causes of death in patients receiving adjuvant HAI and SYS compared to adjuvant SYS alone.METHODS: Between 2000 and 2007, patients undergoing complete CRLM resection were identified from a prospectively maintained liver resection database and categorized as receiving HAI+SYS or SYS only. Using newly constructed definitions, mortality was attributed to specific organs (liver, lung, peritoneum, and brain) or infection. Univariate models and cumulative incidence functions were generated using competing risk methods.RESULTS: Of 361 eligible patients, 208 (57.6%) received HAI+SYS and 153 (42.4%) received SYS. The median follow up among survivors was 142 months (range=12-217 months). Ten-year overall survival was 50.6% in the HAI+SYS group compared to 30.9% in those receiving SYS (P=.004). The 5-year cumulative incidence of liver-related mortality was 6.8% in the HAI+SYS group compared to 14.3% in the SYS group (P=.007).CONCLUSION: The addition of HAI to SYS after CRLM resection is associated with a 50% reduction in liver-related mortality at 5 years.

    View details for DOI 10.1002/jso.25916

    View details for PubMedID 32236970

  • NuSeT: A deep learning tool for reliably separating and analyzing crowded cells PLoS Computational Biology Yang, L., et al 2020
  • Disease-free interval and tumor functional status can be used to select patients for resection/ablation of liver metastases from adrenocortical carcinoma: insights from a multi-institutional study. HPB : the official journal of the International Hepato Pancreato Biliary Association Ayabe, R. I., Narayan, R. R., Ruff, S. M., Wach, M. M., Lo, W. n., Nierop, P. M., Steinberg, S. M., Ripley, R. T., Davis, J. L., Koerkamp, B. G., D'Angelica, M. I., Kingham, T. P., Jarnagin, W. R., Hernandez, J. M. 2020; 22 (1): 169–75

    Abstract

    Adrenocortical carcinoma (ACC) is an aggressive malignancy that frequently metastasizes to the liver. Given the limitations of systemic therapy in this setting, we sought to determine characteristics associated with a two-fold increase in survival with resection/ablation compared to that reported with chemotherapy alone (∼12 months).Patients who underwent resection/ablation at our institutions for ACC liver metastases were identified. Those who survived 12-24 months after metastasectomy were excluded, as the aim was to characterize patients who most clearly benefited from these procedures. Clinicopathologic and treatment characteristics were assessed for associations with survival.Sixty-two patients met inclusion criteria, of whom 44 survived >24 months and 18 survived <12 months. Patients with extended survival were less likely to have functioning tumors (p = 0.047), had fewer liver metastases (p = 0.047), and a longer disease-free interval (DFI) (median 17.6 vs 2.3 months, p < 0.0001). On multivariable analysis, DFI (OR = 1.33, 95% CI = 1.12-1.58) and non-functioning tumor (OR = 0.13, 95% CI = 0.13-0.56) were independently associated with prolonged survival.Metastasectomy/ablation should be considered for patients with ACC liver metastases. DFI and tumor functional status may be useful in selecting optimal candidates for these procedures.

    View details for DOI 10.1016/j.hpb.2019.07.002

    View details for PubMedID 31447392

  • Extrahepatic recurrence rates in patients receiving adjuvant hepatic artery infusion and systemic chemotherapy after complete resection of colorectal liver metastases. Journal of surgical oncology Srouji, R. M., Narayan, R. R., Boerner, T. n., Buisman, F. E., Seier, K. n., Gonen, M. n., Balachandran, V. P., Drebin, J. A., Jarnagin, W. R., Kingham, T. P., Wei, A. n., Kemeny, N. E., D'Angelica, M. I. 2020

    Abstract

    This study investigated the effect of the reduced dose of systemic chemotherapy (SYS) on recurrence patterns in patients receiving adjuvant hepatic artery infusion (HAI) chemotherapy after complete colorectal liver metastases (CRLM) resection.Patients undergoing complete CRLM resection between 2000 and 2007 were selected from a prospectively maintained database and categorized as receiving SYS or HAI + SYS. Those with pre and/or intraoperative extrahepatic disease, documented death, or recurrence within 30 days of CRLM resection were excluded. Competing risk, Fine and Gray's tests were used to compare SYS versus HAI + SYS for time-to-organ recurrence.Of 361 study patients, 153 (42.4%) received SYS and 208 (57.6%) received HAI + SYS. The median follow-up for survivors was 100 (range = 12-185) and 156 months (range = 18-217) for SYS and HAI + SYS, respectively. The 5-year cumulative incidence (CI) of any liver recurrence was greater for those receiving SYS (SYS = 41.9% vs. HAI + SYS = 28.6%, p = .005). The 5-year CI of developing any lung or extrahepatic recurrence for SYS patients was 36.2% and 47.9% compared with 44.5% (p = .242) and 51.7% (p = .551), respectively, in patients receiving HAI + SYS.Despite the reduced dose of SYS, adjuvant HAI + SYS after CRLM resection is not associated with a significantly increased risk of extrahepatic recurrence.

    View details for DOI 10.1002/jso.26221

    View details for PubMedID 32976666

  • Recurrence After Liver Resection of Colorectal Liver Metastases: Repeat Resection or Ablation Followed by Hepatic Arterial Infusion Pump Chemotherapy. Annals of surgical oncology Buisman, F. E., Filipe, W. F., Kemeny, N. E., Narayan, R. R., Srouji, R. M., Balachandran, V. P., Boerner, T. n., Drebin, J. A., Jarnagin, W. R., Kingham, T. P., Wei, A. C., Grünhagen, D. J., Verhoef, C. n., Koerkamp, B. G., D'Angelica, M. I. 2020

    Abstract

    The aim of this study was to investigate the effectiveness of adjuvant hepatic arterial infusion pump (HAIP) chemotherapy after complete resection or ablation of recurrent colorectal liver metastases (CRLM).A retrospective cohort study was conducted of patients from two centers who were treated with resection and/or ablation of recurrent CRLM only between 1992 and 2018. Overall survival (OS) and hepatic disease-free survival (hDFS) were estimated using the Kaplan-Meier method. The Cox regression method was used to calculate hazard ratios (HRs) with corresponding 95% confidence intervals (CI).Of 374 eligible patients, 81 (22%) were treated with adjuvant HAIP chemotherapy. The median follow-up for survivors was 65 months (IQR 32-118 months). Patients receiving adjuvant HAIP were more likely to have multifocal disease and receive perioperative systemic chemotherapy at time of resection for recurrence. A median hDFS of 46 months (95% CI 29-81 months) was found in patients treated with adjuvant HAIP compared with 18 months (95% CI 15-26 months) in patients treated with resection and/or ablation alone (p = 0.001). The median OS and 5-year OS were 89 months (95% CI 52-126 months) and 66%, respectively, in patients treated with adjuvant HAIP compared with 57 months (95% CI 47-67 months) and 47%, respectively, in patients treated with resection and/or ablation only (p = 0.002). Adjuvant HAIP was associated with superior hDFS (adjusted HR 0.599, 95% CI 0.38-0.93, p = 0.02) and OS (adjusted HR 0.59, 95% CI 0.38-0.92, p = 0.02) in multivariable analysis.Adjuvant HAIP chemotherapy after resection and/or ablation of recurrent CRLM is associated with superior hDFS and OS.

    View details for DOI 10.1245/s10434-020-08776-0

    View details for PubMedID 32648182

  • ASO Author Reflections: Perioperative Genomic Profiles and Prognosis of Peripheral and Perihepatic Circulating Tumor DNA in Patients with Colorectal Liver Metastases ANNALS OF SURGICAL ONCOLOGY Narayan, R. R., Kingham, T. 2019; 26: S583–S584
  • 10-Year Experience of Kasai Hepatoportoenterostomy in Biliary Atresia: High-Dose Adjuvant Steroids Improve Outcomes Taylor, J., Abadilla, N., Narayan, R., Pickering, J. M., Bruzoni, M. ELSEVIER SCIENCE INC. 2019: E164
  • Peripheral Circulating Tumor DNA Detection Predicts Poor Outcomes After Liver Resection for Metastatic Colorectal Cancer Narayan, R. R., Goldman, D. A., Gonen, M., Reichel, J., Huberman, K. H., Raj, S., Viale, A., Kemeny, N. E., Allen, P. J., Balachandran, V. P., D'Angelica, M. I., DeMatteo, R. P., Drebin, J. A., Jarnagin, W. R., Kingham, T. SPRINGER. 2019: 1824–32
  • ASO Author Reflections: Perioperative Genomic Profiles and Prognosis of Peripheral and Perihepatic Circulating Tumor DNA in Patients with Colorectal Liver Metastases. Annals of surgical oncology Narayan, R. R., Kingham, T. P. 2019

    View details for PubMedID 30989499

  • Predicting Pathology From Imaging in Children Undergoing Resection of Congenital Lung Lesions Narayan, R. R., Abadilla, N., Greenberg, D. R., Sylvester, K. G., Hintz, S. R., Barth, R. A., Bruzoni, M. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2019: 68–73
  • Regional differences in gallbladder cancer pathogenesis: Insights from a multi-institutional comparison of tumor mutations CANCER Narayan, R. R., Creasy, J. M., Goldman, D. A., Gonen, M., Kandoth, C., Kundra, R., Solit, D. B., Askan, G., Klimstra, D. S., Basturk, O., Allen, P. J., Balachandran, V. P., D'Angelica, M., DeMatteo, R. P., Drebin, J. A., Kingham, T., Simpson, A. L., Abou-Alfa, G. K., Harding, J. J., O'Reilly, E. M., Butte, J. M., Matsuyama, R., Endo, I., Jarnagin, W. R. 2019; 125 (4): 575–85

    View details for DOI 10.1002/cncr.31850

    View details for Web of Science ID 000457532800009

  • Lost in translation: Informed consent in the medical mission setting Sceats, L. A., Morris, A. M., Narayan, R. R., Mezynski, A., Woo, R. K., Yang, G. P. MOSBY-ELSEVIER. 2019: 438–43
  • Peripheral Circulating Tumor DNA Detection Predicts Poor Outcomes After Liver Resection for Metastatic Colorectal Cancer. Annals of surgical oncology Narayan, R. R., Goldman, D. A., Gonen, M., Reichel, J., Huberman, K. H., Raj, S., Viale, A., Kemeny, N. E., Allen, P. J., Balachandran, V. P., D'Angelica, M. I., DeMatteo, R. P., Drebin, J. A., Jarnagin, W. R., Kingham, T. P. 2019

    Abstract

    BACKGROUND: Liver resection can be curative for well-selected metastatic colorectal cancer (CRC) patients. Circulating tumor DNA (ctDNA) has shown promise as a biomarker for tumor dynamics and recurrence following CRC resection. This prospective pilot study investigated the use of ctDNA to predict disease outcome in resected CRC patients.METHODS: Between November 2014 and November 2015, 60 patients with CRC were identified and prospectively enrolled. During liver resection, blood was drawn from peripheral (PERIPH), portal (PV), and hepatic (HV) veins, and 3-4weeks postoperatively from a peripheral vein (POSTOP). Kappa statistics were used to compare mutated (mt) genes in tissue and ctDNA. Disease-specific and disease-free survival (DSS and DFS) were assessed from surgery with Kaplan-Meier and Cox methods.RESULTS: For the 59 eligible patients, the most commonly mutated genes were TP53 (mtTP53: 47.5%) and APC (mtAPC: 50.8%). Substantial to almost-perfect agreement was seen between ctDNA from PERIPH and PV (mtTP53: 89.8%, kappa=0.73, 95% confidence interval [CI] 0.53-0.93; mtAPC: 94.9%, kappa=0.83, 95% CI 0.64-1.00), as well as HV (mtTP53: 91.5%, kappa=0.78, 95% CI 0.60-0.96; mtAPC: 91.5%, kappa=0.73, 95% CI 0.51-0.95). Tumor mutations and PERIPH ctDNA had fair-to-moderate agreement (mtTP53:72.9%, kappa=0.44, 95% CI 0.23-0.66; mtAPC: 61.0%, kappa=0.23, 95% CI 0.04-0.42). Detection of PERIPH mtTP53 was associated with worse 2-year DSS (mt+ 79% vs. mt- 90%, P=0.024).CONCLUSIONS: Peripheral blood reflects the perihepatic ctDNA signature. Disagreement between tissue and ctDNA mutations may reflect the true natural history of tumor genes or an assay limitation. Peripheral ctDNA detection before liver resection is associated with worse DSS.

    View details for PubMedID 30706231

  • Prediction of Recurrence Patterns from Hepatic Parenchymal Disease After Resection of Colorectal Liver Metastases. Annals of surgical oncology Narayan, R. R., Harris, J. W., Chou, J. F., Gönen, M. n., Bao, F. n., Shia, J. n., Allen, P. J., Balachandran, V. P., Drebin, J. A., Jarnagin, W. R., Kemeny, N. E., Kingham, T. P., D'Angelica, M. I. 2019

    Abstract

    Obesity and metabolic syndrome are associated with inflammatory hepatic parenchymal disease (HPD) and increased risk for recurrence after resection of colorectal liver metastases (CRLM). The independent impact of HPD on recurrence patterns has not been well defined.The nonalcoholic fatty liver disease activity score (NAS) was used to quantify HPD including steatosis and fibrosis for all patients with completely resected CRLM between April 2003 and March 2007. Clinicopathologic factors, perioperative history, and outcomes were compared with the NAS. Fisher's exact test was used to examine the association between severe HPD (NAS ≥ 3) with clinical and perioperative characteristics. Kaplan-Meier methods were used to estimate recurrence-free survival (RFS). The cumulative incidences of recurrence [any intrahepatic recurrence (IHR), extrahepatic recurrence only (EHR), and death without recurrence (DWR)] were estimated using competing risks methods.Among the 357 patients included in this study, microsteatosis was noted in 124 (35%) patients, severe HPD in 31 (9%), steatohepatitis in 14 (4%), and sinusoidal injury in 36 (10%). After median follow-up of 127 months (range 4-175 months), 10-year RFS was 22% [95% confidence interval (CI) 17-27%]. Ten-year cumulative incidence for IHR, EHR, and DWR was 37%, 30%, and 12%, respectively. After controlling for confounders, NAS ≥ 3 was independently associated with higher risk of IHR [hazard ratio (HR) 1.76, 95% CI 1.07-2.90, p = 0.027] and lower risk of EHR (HR 0.18, 95% CI 0.04-0.75, p = 0.019) on multivariable analysis.Severe HPD was associated with increased IHR risk and decreased EHR risk. Future investigation into whether improving HPD from reversible etiologies can reduce the risk for IHR is warranted.

    View details for DOI 10.1245/s10434-019-07934-3

    View details for PubMedID 31617122

  • Role of Hepatic Artery Infusion Chemotherapy in Treatment of Initially Unresectable Colorectal Liver Metastases: A Review. JAMA surgery Datta, J. n., Narayan, R. R., Kemeny, N. E., D'Angelica, M. I. 2019

    Abstract

    Although liver metastasis develops in more than half of patients with colorectal cancer, only 15% to 20% of these patients have resectable liver metastasis at presentation. Moreover, patients with initially unresectable colorectal liver metastasis (IU-CRLM) who progress on first-line systemic chemotherapy have limited treatment options. Hepatic arterial infusion chemotherapy (HAIC), in combination with systemic chemotherapy, leverages a multimodality approach to achieving control of hepatic disease and/or expanding resectability in patients with liver-only disease or liver-dominant disease.Intra-arterial delivery of agents with high first-pass hepatic extraction (eg, floxuridine) limits systemic toxic effects and allows for administration of systemic chemotherapy at near-full doses. Hepatic arterial infusion chemotherapy in conjunction with systemic chemotherapy augments response rates up to 92% in patients who are chemotherapy naive, and up to 85% in pretreated patients with IU-CRLM. In turn, these responses translate into encouraging rates of conversion to resectability (CTR). Prospective trials have reported CTR rates as high as 52% in heavily pretreated patients with IU-CRLM who have an extensive hepatic disease burden. As such, CTR remains a compelling indication for liver-directed chemotherapy in this subset of patients. This review discusses the biological rationale for HAIC, evolution of rational combinations with systemic chemotherapy, contemporary evidence for CTR using HAIC and systemic chemotherapy, juxtaposition with rates of CTR using systemic chemotherapy alone, and morbidity and toxic effect profiles of HAIC.The argument is made for consideration of earlier initiation of HAIC in patients with IU-CRLM who are chemotherapy naive and for adoption of HAIC strategies to augment rates of resectability in patients who have failed first-line systemic chemotherapy before proceeding to second-line or third-line regimens.

    View details for DOI 10.1001/jamasurg.2019.1694

    View details for PubMedID 31188415

  • Predicting Pathology From Imaging in Children Undergoing Resection of Congenital Lung Lesions. The Journal of surgical research Narayan, R. R., Abadilla, N., Greenberg, D. R., Sylvester, K. G., Hintz, S. R., Barth, R. A., Bruzoni, M. 2018; 236: 68–73

    Abstract

    BACKGROUND: Prenatal magnetic resonance imaging (MRI) is increasingly obtained to define congenital lung lesions (CLL) for surgical management. Postnatal, preoperative computed tomography (CT) provides further clarity at the cost of radiation. Depending on the lesion identified, the indication for resection remains controversial. We investigated the differences in detail found on prenatal MRI and postnatal CT compared with final pathology to determine their utility in preoperative decision-making.MATERIALS AND METHODS: All children undergoing resection of CLLs at a single institution between July 2009 and February 2018 were retrospectively identified. Their imaging, operative, and pathology reports were compared. All imaging studies were examined by pediatric radiologists with experience in prenatal CLL diagnosis.RESULTS: Fifty-five patients underwent CLL resection during the study period with 31 undergoing prenatal MRI, 45 postnatal CT, and 22 both. Resection was performed before 6 mo of age in 62% of patients. In the cohort undergoing both imaging studies, pathologic CLL diagnosis correlated with prenatal MRI and CT in 82% and 100% of patients, respectively (P=0.13). Eight patients had systemic feeding vessels, of which 38% were identified on MRI, and 88% on CT (P=0.13). Both studies had a specificity of 100% for detecting systemic feeding vessels.CONCLUSIONS: For children where prenatal MRI detected a systemic feeding vessel, CT was redundant for preoperative planning but had greater sensitivity. Ultimately, the CLL type predicted from postnatal CT was not significantly different from that predicted by prenatal MRI; however, both imaging modalities had some level of discrepancy with pathology.

    View details for PubMedID 30694781

  • Pancreaticoduodenectomy with right gastric vessels preservation: impact on intraoperative and postoperative outcomes. ANZ journal of surgery Gagniere, J., Le Roy, B., Veziant, J., Pereira, B., Narayan, R. R., Pezet, D., Buc, E., Dupre, A. 2018

    Abstract

    BACKGROUND: Sympathetic denervation of the antropyloric area combined with relative devascularization from division of the right gastric vessels (RGV) during pancreaticoduodenectomy (PD) could predispose to delayed gastric emptying (DGE). Therefore, some authors advocated for RGV preservation (RGVP), where feasibility and utility for the prevention of post-operative DGE have never been investigated.METHODS: From 2011 to 2014, patients who underwent classic Whipple PD (CWPD, n=34), standard pylorus-preserving PD (PPPD, n=44) or PPPD with RGVP (n=22) were retrospectively analysed.RESULTS: RGVP was not possible in 12% of the cases because of an intraoperative injury of the RGV. There was no difference between CWPD, standard PPPD and PPPD with RGVP in terms of intraoperative blood loss, operative time, number of lymph node harvested and resection margins. Post-operative morbidity and mortality were comparable between the three groups, including rate (27%, 34% and 32%, P=0.77) and severity of DGE, delay in removing nasogastric tube and use of prokinetics. Hospital stay was similar in all the compared groups.CONCLUSION: This is the first study comparing post-operative outcomes after PPPD with RGVP, standard PPPD and CWPD. Although feasible and safe, RGVP during PPPD appeared to offer no obvious clinical benefit in terms of preventing post-operative complications, especially DGE.

    View details for PubMedID 30497109

  • Regional differences in gallbladder cancer pathogenesis: Insights from a multi-institutional comparison of tumor mutations. Cancer Narayan, R. R., Creasy, J. M., Goldman, D. A., Gonen, M., Kandoth, C., Kundra, R., Solit, D. B., Askan, G., Klimstra, D. S., Basturk, O., Allen, P. J., Balachandran, V. P., D'Angelica, M. I., DeMatteo, R. P., Drebin, J. A., Kingham, T. P., Simpson, A. L., Abou-Alfa, G. K., Harding, J. J., O'Reilly, E. M., Butte, J. M., Matsuyama, R., Endo, I., Jarnagin, W. R. 2018

    Abstract

    BACKGROUND: Although rare in the United States, gallbladder cancer (GBCA) is a common cause of cancer death in some parts of the world. To investigate regional differences in pathogenesis and outcomes for GBCA, tumor mutations were analyzed from a sampling of specimens.METHODS: Primary tumors from patients with GBCA who were treated in Chile, Japan, and the United States between 1999 and 2016 underwent targeted sequencing of known cancer-associated genes. Fisher exact and Kruskal-Wallis tests assessed differences in clinicopathologic and genetic factors. Kaplan-Meier methods evaluated differences in overall survival from the time of surgery between mutations.RESULTS: A total of 81 patients were included. Japanese patients (11 patients) were older (median age, 72 years [range, 54-81 years]) compared with patients from Chile (21 patients; median age, 59 years [range, 32-73 years]) and the United States (49 patients; median age, 66 years [range, 46-87 years]) (P=.002) and had more well-differentiated tumors (46% vs 0% for Chile/United States; P<.001) and fewer gallstone-associated cancers (36% vs 67% for Chile and 69% for the United States; P=.13). Japanese patients had a median mutation burden of 6 (range, 1-23) compared with Chile (median mutation burden, 7 [range, 3-20]) and the United States (median mutation burden, 4 [range, 0-27]) (P=.006). Tumors from Japanese patients lacked AT-rich interaction domain 1A (ARID1A) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutations, whereas Chilean tumors lacked Erb-B2 receptor tyrosine kinase 3 (ERBB3) and AT-rich interaction domain 2 (ARID2) mutations. SMAD family member 4 (SMAD4) was found to be mutated similarly across centers (38% in Chile, 36% in Japan, and 27% in the United States; P=.68) and was univariately associated with worse overall survival (median, 10 months vs 25 months; P=.039). At least one potentially actionable gene was found to be altered in 80% of tumors.CONCLUSIONS: Differences in clinicopathologic variables suggest the possibility of distinct GBCA pathogenesis in Japanese patients, which may be supported by differences in mutation pattern. Among all centers, SMAD4 mutations were detected in approximately one-third of patients and may represent a converging factor associated with worse survival. The majority of patients carried mutations in actionable gene targets, which may inform the design of future trials.

    View details for PubMedID 30427539

  • Lost in translation: Informed consent in the medical mission setting. Surgery Sceats, L. A., Morris, A. M., Narayan, R. R., Mezynski, A., Woo, R. K., Yang, G. P. 2018

    Abstract

    BACKGROUND: Informed consent is a fundamental tenet of ethical care, but even under favorable conditions, patient comprehension of consent conversations may be limited. Little is known about providing informed consent in more uncertain situations such as medical missions. We sought to examine the informed consent process in the medical mission setting.METHODS: We studied informed consent for adult patients undergoing inguinal herniorrhaphy during a medical mission to Guatemala using a convergent mixed-methods design. We audiotaped informed consents during preoperative visits and immediately conducted separate surveys to elicit comprehension of risks. Informed consent conversations and survey responses were translated and transcribed. We used descriptive statistics to examine informed consent content, including information provided by surgeon, the translation of information, and patient comprehension, and used thematic analysis to examine the consent process.RESULTS: Thirteen adult patients (median age 53 years, 69% male) participated. Surgeons conveyed 4 standard risks in 10 out of 13 encounters (77%); all 4 risks were translated to patients in 10 out of 13 encounters (77%). No patient could recall all 4 risks. Qualitative themes regarding the informed consent process included limited physician language skills, verbal domination by physicians and interpreters, and mistranslation of risks. Patients relied on faith and prior or vicarious experiences to qualify surgical risks instead of consent conversations. Many patients restated surgical instructions when asked about risks.CONCLUSION: Despite physicians' attempts to provide informed consent, medical mission patients did not comprehend surgical risks. Our data reveal a critical need to develop more effective methods for communicating surgical risks during medical missions.

    View details for PubMedID 30061041

  • Robotic-Assisted Lobectomies in the National Cancer Database JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS Arnold, B. N., Thomas, D. C., Narayan, R., Blasberg, J. D., Detterbeck, F. C., Boffa, D. J., Kim, A. W. 2018; 226 (6): 1052–62

    Abstract

    Robotic-assisted thoracoscopic surgery (RobATS) lobectomy is becoming more common for the treatment of lung cancer. As with any relatively new technology, there is the assumption that greater experience leads to greater proficiency. The objective of this study was to analyze outcomes of patients undergoing RobATS lobectomy as hospitals gain experience, and to describe outcomes after conversion to open procedures.The National Cancer Database (NCDB) was used to analyze robotic lobectomies for lung cancer from 2010 to 2014. Individual hospitals were categorized by the year they began reporting robotic lobectomies to the NCDB. Primary outcomes were perioperative morbidity and mortality and rate of conversion to open lobectomy.There were 7,645 robotic lobectomies identified from 465 hospitals. The overall conversion rate was 9.2% (n = 702). A propensity-matched analysis showed no significant difference between experienced and inexperienced hospitals with respect to 30-day mortality (1.07% vs 2.03%, p = 0.092) or 90-day mortality (2.35% vs 3.63%, p = 0.104). Conversion to open was a predictor of 30-day mortality (odds ratio [OR] 2.54, CI 1.56 to 4.14) and 90-day mortality (OR 2.68, CI 1.83 to 3.91). Patients who underwent conversion had higher 90-day mortality compared with patients not undergoing conversion, in years of experience: 2 (p = 0.043), 3 (p = 0.002), and 4 (p = 0.003).Mortality after RobATS lobectomy at experienced hospitals is not significantly different than at inexperienced hospitals. Though conversion rates decrease with experience, patients who undergo conversion have higher mortality than those who do not, particularly in hospitals with more experience. This suggests that a deliberate effort to increase experience with and improve patient selection for RobATS lobectomies may ameliorate the conversions and their attendant sequelae.

    View details for DOI 10.1016/j.jamcollsurg.2018.03.023

    View details for Web of Science ID 000433087400025

    View details for PubMedID 29574177

  • Predicting Pathology from Imaging in Children Undergoing Resection of Congenital Pulmonary Malformations Narayan, R. R., Abadilla, N., Greenberg, D. R., Bruzoni, M. ELSEVIER SCIENCE INC. 2017: S154
  • Extracorporeal Hypothermic Perfusion Device for Intestinal Graft Preservation to Decrease Ischemic Injury During Transportation JOURNAL OF GASTROINTESTINAL SURGERY Munoz-Abraham, A., Patron-Lozano, R., Narayan, R. R., Judeeba, S. S., Alkukhun, A., Alfadda, T. I., Belter, J. T., Mulligan, D. C., Morotti, R., Zinter, J. P., Geibel, J. P., Rodriguez-Davalos, M. I. 2016; 20 (2): 313-321

    Abstract

    The small intestine is one of the most ischemia-sensitive organs used in transplantation. To better preserve the intestinal graft viability and decrease ischemia-reperfusion injury, a device for extracorporeal perfusion was developed. We present the results for the first series of perfused human intestine with an intestinal perfusion unit (IPU).Five human intestines were procured for the protocol. (1) An experimental segment was perfused by the IPU delivering cold preservation solution to the vascular and luminal side continually at 4 ºC for 8 h. (2) Control (jejunum and ileum) segments were preserved in static cold preservation. Tissue samples were obtained for histopathologic grading according to the Park/Chiu scoring system (0 = normal, 8 = transmural infarction).Jejunal experimental segments scored 2.2 with the Park/Chiu system compared to the control segments, which averaged 3.2. Overall scoring for ileum experimental and control segments was equal with 1.6.This data presents proof of concept that extracorporeal intestinal perfusion is feasible. The evidence shows that the IPU can preserve the viability of human intestine, and histopathologic evaluation of perfused intestine is favorable. Our early results can eventually lead to expanding the possibilities of intestinal preservation.

    View details for DOI 10.1007/s11605-015-2986-x

    View details for Web of Science ID 000373158900021

    View details for PubMedID 26487331

  • Vascular reconstruction plays an important role in the treatment of pancreatic adenocarcinoma. Journal of vascular surgery Sgroi, M. D., Narayan, R. R., Lane, J. S., Demirjian, A. n., Kabutey, N. K., Fujitani, R. M., Imagawa, D. K. 2015; 61 (2): 475–80

    Abstract

    Previous studies have proved the feasibility of performing a pancreaticoduodenectomy (Whipple operation) in patients with portal vein-superior mesenteric vein and hepatic artery invasion. We report our institutional experience with the use of a variety of vascular reconstructive methods during pancreatic resections for adenocarcinoma.A retrospective review was performed identifying all patients undergoing a Whipple operation or total pancreatectomy procedure from January 2003 to December 2013. All venous (portal vein-superior mesenteric vein) and arterial (superior mesenteric artery-hepatic artery) reconstructions were extracted and reviewed to determine survival and perioperative complications.During the 10-year study period, 270 Whipple and total pancreatectomy procedures were performed, of which 183 were for adenocarcinoma of the pancreas. Of the 183 operations, a total of 60 (32.8%) vascular reconstructions were found, 49 venous and 11 arterial. Venous reconstruction included 37 (61.7%) primary repairs, four (6.7%) reconstructions with CryoVein (CryoLife, Inc, Kennesaw, Ga), three (5.0%) repairs with autologous vein patch, three (5.0%) autologous saphenous reconstructions, and two (3.33%) portacaval shunts. In addition, there were 11 (18.3%) arterial reconstructions (seven hepatic artery and four superior mesenteric artery). The 1-year survival for all reconstructions was 71.1%, which is equivalent to T3 lesions that did not receive vascular reconstruction (70.11%), with a median survival time of 575.28 days and 12 patients still alive. Survival time was comparable with each type of venous reconstruction, averaging 528 days (11 of 49 patients still alive). There was a total thrombosis rate of seven of 60 (11.6%), all of which were portal vein thrombosis: three in the primary repair group and four delayed thromboses seen in primary repair, CryoVein repair, and vein patch repair. There was no thrombosis in any patients after arterial reconstruction.An aggressive approach for stage II pancreatic cancers with venous or arterial invasion can be performed with comparable results when it is executed by an experienced institution with skilled oncologic and vascular surgeons.

    View details for DOI 10.1016/j.jvs.2014.09.003

    View details for PubMedID 25441672

  • A Paradigm Shift in Trauma Resuscitation Evaluation of Evolving Massive Transfusion Practices JAMA SURGERY Kutcher, M. E., Kornblith, L. Z., Narayan, R., Curd, V., Daley, A. T., Redick, B. J., Nelson, M. F., Fiebig, E. W., Cohen, M. J. 2013; 148 (9): 834-840

    Abstract

    The evolution of damage control strategies has led to significant changes in the use of resuscitation after traumatic injury.To evaluate changes in the administration of fluids and blood products, hypothesizing that a reduction in crystalloid volume and a reduced red blood cell (RBC) to fresh frozen plasma (FFP) ratio over the last 7 years would correlate with better resuscitation outcomes.Observational prospective cohort study.Urban level I trauma center.A total of 174 trauma patients receiving a massive transfusion (>10 units of RBCs in 24 hours) or requiring the activation of the institutional massive transfusion protocol from February 2005 to June 2011.Patients had to either receive a massive transfusion or require the activation of the institutional massive transfusion protocol.In-hospital mortality.The mean (SD) Injury Severity Score was 28.4 (16.2), the mean (SD) base deficit was -9.8 (6.3), and median international normalized ratio was 1.3 (interquartile range, 1.2-1.6); the mortality rate was 40.8%. Patients received a median of 6.1 L of crystalloid, 13 units of RBCs, 10 units of FFP, and 1 unit of platelets over 24 hours, with a mean RBC:FFP ratio of 1.58:1. The mean 24-hour crystalloid infusion volume and number of the total blood product units given in the first 24 hours decreased significantly over the study period (P < .05). The RBC:FFP ratio decreased from a peak of 1.84:1 in 2007 to 1.55:1 in 2011 (P = .20). Injury severity and mortality remained stable over the study period. When adjusted for age and injury characteristics using Cox regression, each decrease of 0.1 achieved in the massive transfusion protocol's RBC:FFP ratio was associated with a 5.6% reduction in mortality (P = .005).There has been a shift toward a reduced crystalloid volume and the recreation of whole blood from component products in resuscitation. These changes are associated with markedly improved outcomes and a new paradigm in the resuscitation of severely injured patients.

    View details for DOI 10.1001/jamasurg.2013.2911

    View details for Web of Science ID 000325212300011

    View details for PubMedID 23864019

  • Total Synthesis of (+)-Lyconadin A and Related Compounds via Oxidative C-N Bond Formation JOURNAL OF THE AMERICAN CHEMICAL SOCIETY West, S. P., Bisai, A., Lim, A. D., Narayan, R. R., Sarpong, R. 2009; 131 (31): 11187-11194

    Abstract

    The formation of carbon-nitrogen (C-N) bonds is a fundamental bond construction in organic synthesis and is indispensable for the synthesis of alkaloid natural products. In the context of the synthesis of the architecturally complex Lycopodium alkaloid lyconadin A, we have discovered a highly efficient oxidative C-N bond forming reaction that relies on the union of a nitrogen anion and a carbon anion. Empirical evidence amassed during our synthetic studies suggests that the mechanism of the C-N bond forming process encompasses polar as well as radical processes. Herein, we present our study of this novel C-N bond forming reaction and its application to the enantioselective total synthesis of lyconadin A and related derivatives.

    View details for DOI 10.1021/ja903868n

    View details for Web of Science ID 000268806500072

    View details for PubMedID 19591469