Long Term Follow-Up Observation in Small Choroidal Melanocytic Tumors.

Background: The purpose of this study is to analyze the long-term evolution of patients with small choroidal melanocytic tumors (SCMTs) undergoing observation, and to assess their rate of transformation into melanomas and survival.

Methods: A retrospective single-cohort study of patients with SCMTs (1-3 mm in height and 5-10 mm in base) diagnosed from January 1992 to February 2023 was carried out, with observation as the initial treatment. The main criterion for a transformation into melanoma is considered to be an increase in size of more than 1 mm in height and/or more than 1 mm in base measured on an ultrasound/retinography, recorded in two consecutive visits separated by one to three months.

Results: 243 patients were included with a mean age of 65.3 years and a mean follow-up of 7.9 years (6 months-27.9 years); 27 patients showed tumor growth. The probabilities of growth at 5, 10, and 15 years are 10%, 14%, and 17%, respectively. Regarding survival, 22 patients died and only 3 deaths were due to melanoma metastasis. Survival rates at 5 and 10 years are 99% and 97%.

Conclusions: Observation is a viable therapeutic option for SCMTs, avoiding the side effects of treatment, considering the majority of these tumors do not progress to melanoma. With close monitoring, patients can be treated promptly upon detecting a transformation. Additionally, the findings confirm that small melanocytic tumors can lead to metastatic disease, albeit at a low rate.