Risk factors for growth and metastasis of small choroidal melanocytic lesions

To investigate the clinical features that predict growth and metastasis of an unselected group of small melanocytic choroidal tumors.

A retrospective review was performed on 1329 patients with small melanocytic choroidal tumors measuring 3 mm in thickness or less. Clinical parameters of the patient and tumor were extracted and analyzed for their relationship to eventual tumor growth and metastasis using a Cox proportional hazards regression model.

Tumor growth was documented in 18% of patients. The factors predictive of tumor growth (multivariate analysis) included greater tumor thickness, posterior tumor margin touching optic disc, symptoms of flashes, floaters, and blurred vision, orange pigment on the tumor surface, and the presence of subretinal fluid. The relative risk (rr) was greatest for initial tumor thickness > 2.0 mm (rr 5.2) and posterior margin touching the optic disc (rr 2.6). After adjusting for significant tumor variables, the effect of interventional tumor treatment showed a decreasing risk for tumor growth as compared to continued observation without treatment. Of 1329 patients, 35 (3%) developed metastases. The factors predictive of metastases (multivariate analysis) included: posterior tumor margin touching the optic disc, documented growth, and greater tumor thickness. The relative risk for metastases was greatest for tumor thickness 1.1-3.0 mm (rr 8.8) and growth (rr 3.2).

Of small choroidal melanocytic tumors measuring 3 mm or less in thickness at the time of initial examination, 18% demonstrate growth and 3% metastasize during the period of followup. Based on this analysis, the clinical features of these tumors can be used to estimate the risk for tumor growth and metastases and assist the clinician with patient management.