Survival in small choroidal melanocytic lesions with risk factors managed by initial observation until detection of tumour growth

Background The main objective was to describe metastatic and survival rates in patients with small choroidal melanocytic lesions initially managed by observation. Methods Retrospective, observational study of consecutive cases recruited from 2001 through 2018, followed for a median (mean, range) of 81.0 (89.3, 10‐204) months in a tertiary referral centre for ocular oncology. Seventy‐five consecutive patients diagnosed with small choroidal melanocytic lesions with risk factors for growth initially observed and who showed progression during follow‐up. Treatment was performed (plaque radiotherapy or enucleation in 96% and 4% of cases, respectively) at detection of tumour growth. Results Median (mean, range) tumour thickness was 2.2 (2.23, 1.08‐3.40) mm, and median maximum basal diameter was 8.5 (8.16, 4‐12) mm. At diagnosis, a median (mean, range) of 5 (5.48, 1‐8) risk factors for progression were present. Lesions grew at a median (mean, range) rate of 0.42 mm/y (1.12, 0‐7.68) in thickness and 1.05 mm/y (3.14, 0‐4.8) in maximum diameter. Median (mean, range) time until growth was 17.00 (32.6, 1‐161) months post‐diagnosis, at which time tumours were treated. Five patients developed local recurrence after brachytherapy requiring enucleation. Four patients developed hepatic metastasis. Melanoma‐specific survival was 98% at 5 years (95% CI, 94.2‐100%) and 91.6% (95% CI, 82‐100%) at 10 and 15 years. Conclusion In small melanocytic lesions with risk factors for growth, initial observation until detection of tumour growth results in a seemingly low risk of metastasis, suggesting that this may be an initial approach to consider in tumours with indeterminate malignant potential.