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

AIMS: To develop a nomogram for prediction of visual acuity outcome following plaque radiotherapy for uveal melanoma.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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/.