Small-sized Choroidal Melanoma Study
Small melanomas can be watched for growth prior to treatment. Should growth occur, then the patient knows the melanoma will eventually destroy the vision and increase the chance that cancer cells will spread to other parts of the body. The Collaborative Ocular Melanoma Study (COMS) was interested in how many small melanomas would grow and over what period of time. The COMS found that more than 25% of small melanomas were found to grow (within 2 years of follow-up). Since choroidal melanoma growth is the best predictor for vision loss and increased risk of metastasis, this COMS finding underscores the need to follow patients with small melanomas closely after diagnosis.
Medium-sized Choroidal Melanoma Study
The medium-sized tumor study was designed to determine if iodine-125 plaque-irradiation is better, equal, or worse than enucleation (removal of the eye) for the prevention of metastasis. In this study, half of enrolled patients were treated by enucleation and the other half underwent plaque radiation therapy. Patients were followed for evidence of recurrence and metastatic melanoma.
The COMS medium-tumor trial concluded that there is no significant difference between these two treatment options with respect to survival. COMS centers had followed 80% of patients for at least 5 years at the time they issued their report. Therefore, COMS found no evidence that removing the eye is a better treatment than iodine-125 plaque radiation therapy for preventing spread of choroidal melanomas.
Large-sized Choroidal Melanoma Study
Large-melanoma trial was designed to see if radiation before enucleation (removal of the eye) would prevent metastasis. The idea was to see if pre-operative irradiation would sterilize any cells that might break free during surgery. The other half of the patients did not receive radiation before their surgery.
The Large-sized Choroidal Melanoma Study concluded that patients who received 2000 rads (cGy) of external irradiation to their eye before it was removed, had an equal chance of developing metastatic disease as compared to those who were treated by enucleation (removal of the eye) alone.