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  • Vision loss following high-dose proton-based radiotherapy for skull-base chordoma and chondrosarcoma RADIOTHERAPY AND ONCOLOGY De Leo, A. N., Holtzman, A. L., Ho, M., Morris, C. G., Rutenberg, M. S., Rotondo, R. L., Bates, J. E., Indelicato, D. J., Rao, D., Hasan, M., Mendenhall, W. M. 2021; 158: 125-130

    Abstract

    Dose escalation for skull-based chordoma and chondrosarcoma can put critical adjacent structures at risk, specifically the anterior optic pathway. We report the incidence of vision loss following high-dose conformal proton-based radiotherapy.We reviewed patients with skull-base chordoma or chondrosarcoma treated with proton-based therapy between 2007 and 2018. We analyzed 148 patients and 283 individual eyes with functional vision at baseline who received a minimum 30GyRBE to 0.1 cm3 of the anterior optic pathway. Eyes were classified as "functionally blind" if visual acuity was 20/200 or worse. Kaplan-Meier and normal tissue complication probability modeling were used to establish the relationship between radiation dose and risk of functional vision loss.At last follow-up, 110 of 148 patients were alive with no evidence of disease progression. With a median follow-up of 4.1 years (range, 0.5-12.8), 5 eyes in 3 patients developed functional blindness, with 2 patients developing bilateral blindness. Median time to blindness was 15.2 months. The 5-year incidence of vision loss was 2.1% (95% CI: 0.9-4.9%). On univariate analysis, development of blindness was associated with presence of multiple medical comorbidities (p = 0.0040). While there were no events with a maximum dose < 60GyRBE delivered to the anterior optic pathway, the crude rate was 3.6% over 60GyRBE, with all events occurring between 60-65GyRBE.Despite the high radiotherapy dose delivered to patients with skull-base chordoma and chondrosarcoma, the rate of vision loss is low and no events occurred in those who received a maximum dose under 60GyRBE.

    View details for DOI 10.1016/j.radonc.2021.02.012

    View details for Web of Science ID 000648874300018

    View details for PubMedID 33610625