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.

Intralesional Vessel Diameter Measured by Optical Coherence Tomography Angiography Could Improve the Differential Diagnosis of Small Melanocytic Choroidal Lesions.

In this study, we aimed to identify the features of indeterminate choroidal melanocytic lesions visualized on optical coherence tomography angiography (OCTA) and to identify the predictors of growth. We retrospectively evaluated 86 patients with indeterminate lesions treated at our centre from 2016 to 2021. Clinical management involved active surveillance followed by brachytherapy if growth was detected. The lesions were classified into two groups according to whether they grew (small melanomas) or remained stable (choroidal nevi). Growth was detected in 19 (22.1%) lesions. All patients underwent OCTA at baseline. These images were compared to identify the possible predictors of growth. Significant between-group differences were observed in thickness (p = 0.00), greatest basal diameter (p = 0.00), number of risk factors (p = 0.00), symptoms (p = 0.001; relative risk [RR]: 4.3), orange pigment (p = 0.00; RR: 6.02), and ultrasonographic hollowness (Kappa sign); p = 0.000; RR: 5.3). The melanomas had significantly more vessels with a diameter ≥ 76.3 µm (p = 0.02; RR: 2.46). The time to growth in these lesions was significantly shorter (p = 0.05) than in lesions with smaller vessels. These findings show that vessel diameter quantified by OCTA can help differentiate between choroidal nevi and small melanomas, when considered together with clinical risk factors.