Prognosis of uveal melanoma in 500 cases using genetic testing of fine-needle aspiration biopsy specimens

Purpose: To determine the relationship between monosomy 3 and incidence of metastasis after genetic testing of uveal melanoma using fine-needle aspiration biopsy (FNAB).

Design: Noncomparative retrospective case series.

Participants: Five hundred patients.

Methods: Fine-needle aspiration biopsy was performed intraoperatively immediately before plaque radiotherapy. The specimen underwent genetic analysis using DNA amplification and microsatellite assay. Systemic follow-up was obtained regarding melanoma-related metastasis.

Main outcome measures: Presence of chromosome 3 monosomy (loss of heterozygosity) and occurrence of melanoma metastasis.

Results: Disomy 3 was found in 241 melanomas (48%), partial monosomy 3 was found in 133 melanomas (27%), and complete monosomy 3 was found in 126 melanomas (25%). The cumulative probability for metastasis by 3 years was 2.6% for disomy 3, 5.3% for partial monosomy 3 (equivocal monosomy 3), and 24.0% for complete monosomy 3. At 3 years, for tumors with disomy 3, the cumulative probability of metastasis was 0% for small (0-3 mm thickness), 1.4% for medium (3.1-8 mm thickness), and 23.1% for large (>8 mm thickness) melanomas. At 3 years, for tumors with partial monosomy 3, the cumulative probability of metastasis was 4.5% for small, 6.9% for medium, and [insufficient numbers] for large melanomas. At 3 years, for tumors with complete monosomy 3, the cumulative probability of metastasis was 0% for small, 24.4% for medium, and 57.5% for large melanomas. The most important factors predictive of partial or complete monosomy 3 included increasing tumor thickness (P = 0.001) and increasing distance to optic disc (P = 0.002).

Conclusions: According to FNAB results, patients with uveal melanoma demonstrating complete monosomy 3 have substantially poorer prognosis at 3 years than those with partial monosomy 3 or disomy 3. Patients with partial monosomy 3 do not significantly differ in outcome from those with disomy 3.