Scleral necrosis after plaque radiotherapy of uveal melanoma: a case-control study.
OBJECTIVE
To identify risk factors and outcome of scleral necrosis after plaque radiotherapy of uveal melanoma.


METHODS
Case-control study.


METHODS
A total of 73 cases with scleral necrosis and 73 controls without necrosis after plaque radiotherapy. Controls were matched for anteroposterior tumor epicenter and follow-up duration.


METHODS
Plaque radiotherapy with iodine-125, cobalt-60, iridium-192, or ruthenium-106.


METHODS
Scleral necrosis.


RESULTS
Of 5057 patients treated with plaque radiotherapy for uveal melanoma, 73 (1%) developed radiotherapy-induced scleral necrosis. Scleral necrosis occurred in <1% of patients (3/1140) when plaque radiotherapy was used for tumors <3 mm in thickness, 1% of patients (33/3155) with 3- to 8-mm tumor thickness, and 5% of patients (37/762) with >8-mm-thick tumors. On the basis of tumor location, scleral necrosis was detected after plaque radiotherapy of iris melanoma in 0% of patients (0/91), ciliary body melanoma in 29% of patients (67/235), and choroid melanoma in <1% of patients (6/4731). The mean time interval between plaque radiotherapy and scleral necrosis was 32 months (median, 23 months; range, 4-126 months). The mean basal dimension of scleral necrosis was 4 mm (median, 3 mm; range, 1-15 mm), equivalent to 29% of mean tumor base (median, 24%; range, 6%-100%) and 22% of mean plaque size (median, 19%; range, 5%-75%). Multivariate analysis of factors that predicted clinically evident scleral necrosis included ciliary body (P = 0.0001) and pars plana to ora serrata (P < 0.0001) locations of anterior tumor margin, tumor thickness ≥ 6 mm (P = 0.0001), and radiation dose ≥ 400 Gy to the outer sclera (P = 0.0455). Scleral necrosis remained stable in 48% of patients (35/73), increased in size/severity in 48% of patients (35/73), or progressed to scleral perforation in 4% of patients (3/73) over a mean follow-up of 79 months (median, 54 months; range, 5-351 months). Treatment of scleral necrosis included observation in 81% of patients (59/73), scleral patch graft in 14% of patients (10/73), and enucleation in 5% of patients (4/73).


CONCLUSIONS
Scleral necrosis after plaque radiotherapy of uveal melanoma was detected in 1% of cases. Factors predictive of scleral necrosis included increasing tumor thickness, ciliary body and peripheral choroidal location, and higher radiation dose to sclera. Most patients (81%) did not require treatment, and 4% evolved to full-thickness perforation.


BACKGROUND
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Ocular Oncology Service, Wills Eye Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Swathi
S
Kaliki
Carol L
CL
Shields
Duangnate
D
Rojanaporn
Josep
J
Badal
Laxmi
L
Devisetty
Jacqueline
J
Emrich
Lydia
L
Komarnicky
Jerry A
JA
Shields
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000532:radiotherapy*; D008875:Middle Aged; D009336:Necrosis / Q000473:pathology; D011832:Radiation Injuries / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D012590:Sclera / Q000473:pathology* / Q000528:radiation effects*; D014604:Uveal Neoplasms / Q000532:radiotherapy*; D055815:Young Adult