Nomogram for visual acuity outcome after iodine-125 plaque radiotherapy and prophylactic intravitreal bevacizumab for uveal melanoma in 1131 patients.

Abstract

To develop a nomogram for prediction of visual acuity outcome following plaque radiotherapy for uveal melanoma. Retrospective review of uveal melanoma treated with plaque radiotherapy and prophylactic intravitreal bevacizumab injections at 4-month intervals for 2 years duration. Two nomograms for poor visual acuity outcome (Snellen <20/200) were developed based on (1) Clinical risk factors. (2) Or clinical and treatment risk factors. There were 1131 included cases. The most important clinical risk factors (points for nomogram) for poor visual acuity outcome included subretinal fluid involving four quadrants (100), tumour thickness >4 mm (69), presenting visual acuity ≤20/30 (65), non-Caucasian race (58), tumour shape mushroom, bilobed, or multilobulated (57), and insulin-dependent diabetes (54). Risk of poor visual acuity at 2 years and 4 years increased from 11% and 24% with 40 points to 97% and >99% with 304 points. A second analysis was performed using both clinical and treatment risk factors. The most important factors included presenting visual acuity ≤20/30 (100), tumour largest basal diameter >11 mm (80), radiation dose rate to tumour base ≥164 cGy/hour (78), tumour thickness >4 mm (76), insulin-dependent diabetes (75) and abnormal foveolar status by optical coherence tomography at presentation (72). Risk of poor visual acuity at 2 years and 4 years increased from 6% and 14% with 56 points to 88% and 99% with 496 points. A nomogram using clinical or treatment risk factors can predict visual acuity outcome following plaque radiotherapy and prophylactic intravitreal bevacizumab for uveal melanoma and is available online at https://fighteyecancer.com/nomograms/.