Second Primary Cancers After Enrollment in the COMS Trials for Treatment of Choroidal Melanoma

Abstract

To report sites of second primary cancer and the time to first diagnosis during routine follow-up after treatment for choroidal melanoma. Prospective longitudinal follow-up of patients enrolled in 2 randomized trials conducted by the Collaborative Ocular Melanoma Study (COMS) Group. Baseline and annual or semiannual systemic and laboratory evaluations were performed according to a standard protocol for 2320 patients enrolled in the COMS without evidence of melanoma metastasis or other primary cancer at baseline. Deaths were coded by a mortality coding committee. Subsequent to treatment for choroidal melanoma, a total of 222 patients were diagnosed with a second primary cancer other than basal or squamous cell skin cancer (5-year rate of 7.7% [95% confidence interval, 6.6%-9.0%]). The most common sites were prostate (23% of reported cases) and breast (17%); 12 of these 222 patients were diagnosed simultaneously with second primary cancers in 2 or more sites. Of these 222 patients, 113 died; 37 (33%) were coded as dead with melanoma metastasis, 33 (29%) as dead with a malignant tumor other than metastatic melanoma, and 13 (11%) as dead with a malignancy of uncertain origin. Radiotherapy did not significantly increase the development of second primary cancers. The rate of diagnosis of second primary cancer did not differ significantly by smoking status, although the rate in former smokers was increased vs that observed in either current smokers or those who never smoked. Routine medical surveillance for development of second primary cancers among patients treated for choroidal melanoma is important, especially for those with a history of smoking, regardless of the size of choroidal melanoma at the time of treatment.