Estimates of ocular and visual retention following treatment of extra-large uveal melanomas by proton beam radiotherapy.

OBJECTIVE To assess outcomes of proton beam radiotherapy for the treatment of extra-large uveal melanomas in patients specifically referred to the University of California, San Francisco, for ocular conservation therapy. Series patients uniformly refused enucleation both at an outside institution and again as a treatment option after extensive discussion at the University of California, San Francisco. DESIGN In a retrospective, nonrandomized cohort study, 21 patients with extra-large choroidal or ciliochoroidal melanomas measuring at least 10 mm in maximum thickness or 20 mm in maximum basal diameter or tumors located within 3 mm of the optic nerve measuring at least 8 mm in maximum thickness or 16 mm in maximum basal diameter met inclusion criteria. Main outcome measures were frequency of (1) anterior segment complications (lash loss, keratopathy, cataract, and neovascular glaucoma), (2) posterior segment complications (vitreous hemorrhage, radiation retinopathy, and radiation papillopathy), (3) treatment failure (tumor growth, enucleation, or metastases), and (4) final visual acuity. RESULTS Median follow-up was 28 months. Mean age at treatment was 58.3 years. The frequencies of hypertension and diabetes mellitus were 14.3% and 9.5%, respectively. Mean tumor thickness and mean basal diameter were 8.6 mm and 18.7 mm, respectively. Lash loss occurred in 52.4%; dry eye, in 23.8%; cataract, in 28.6%; neovascular glaucoma, in 38.1% (100% in patients with diabetes mellitus); radiation retinopathy, in 9.5%; and radiation papillopathy, in 9.5%. No patient developed radiation-associated scleral necrosis or vitreous hemorrhage. The 2-year Kaplan-Meier estimate of local tumor growth after treatment was 33%, and the rate of distant metastasis was 10%. Visual acuity of 20/200 or better was preserved in 25% of patients, including 4 patients (19%) who experienced an average of 4 lines of Snellen visual acuity improvement. Development of neovascular glaucoma was associated with tumors in close proximity to the optic nerve (P = .04), while cataract (P = .03) and lash loss (P = .02) occurred with more anteriorly located tumors. Proton beam radiotherapy provided a 67% probability of local control and 90% probability of clinically discernible metastases-free survival at 24 months after treatment. CONCLUSION Proton beam radiotherapy is an ocular-conserving option that may be considered for the treatment of extra-large uveal melanoma in carefully selected patients.