REGRESSION OF UVEAL MELANOMA AFTER PLAQUE RADIOTHERAPY AND THERMOTHERAPY BASED ON CHROMOSOME 3 STATUS

Abstract

To evaluate regression rates after plaque radiotherapy and thermotherapy of uveal melanoma with chromosome 3 monosomy versus disomy. Noncomparative case series. Two hundred and seventy patients with uveal melanoma. Fine needle aspiration biopsy was used at the time of plaque radiotherapy to sample tumor cells for genetic testing. Tumor thickness regression based on chromosome 3 status. At the time of plaque radiotherapy, the median tumor thickness was 4.0 mm for melanomas with chromosome 3 monosomy and 3.5 mm for those with disomy 3. The median tumor thickness (% original thickness) at 4, 8, 12, 15, and 18 months after radiotherapy for melanoma with monosomy 3 was 77%, 67%, 58%, 55%, and 50% and for those with disomy 3 was 82%, 70%, 69%, 67%, and 61%. The median monthly regression rate was 3.1% for tumors with monosomy 3 and 2.7% for those with disomy 3. The overall regression and monthly rate of regression was statistically greater at 12 months (P < 0.001) and 15 months (P = 0.003) for melanomas with monosomy 3 compared with disomy 3. Uveal melanomas with chromosome 3 monosomy showed faster and greater tumor thickness regression at 12 and 15 months after plaque radiotherapy and thermotherapy than melanomas with disomy 3.