DESIGN AND METHODS OF A CLINICAL-TRIAL FOR A RARE CONDITION - THE COLLABORATIVE OCULAR MELANOMA STUDY - COMS REPORT NO 3

Investigators who conduct clinical trials of treatments for uncommon c onditions face special challenges regarding trial design and execution in addition to the challenges faced by all clinical trial investigato rs. The Collaborative Ocular Melanoma Study (COMS) currently consists of two multicenter, randomized controlled clinical trials designed to investigate the efficacy of radiotherapy compared to surgery in prolon ging the survival of patients with choroidal melanoma, a rare intraocu lar cancer. Patients with unilateral choroidal melanoma classified as ''medium'' in size are randomized with equal probability to either enu cleation (removal of the eye) or radiation delivered to the tumor by m eans of a radioactive ''plaque'' attached by sutures to the scleral su rface of the eye over the base of the tumor. Patients with large tumor s are randomized with equal probability to either enucleation or a 5 d ay course of external beam radiation therapy followed by enucleation. Time to death is the primary outcome; patients will be followed for at least 10 years or until death. Quality assurance mechanisms for evalu ation, treatment, and follow-up have been implemented. This paper desc ribes the design and methods of the trials, highlights the challenges associated with implementing and conducting the study, and summarizes the current status of the study.