Hypofractionated stereotactic photon radiotherapy of posteriorly located choroidal melanoma with five fractions at ten Gy – Clinical results after six years of experience

Abstract

PurposeTo evaluate long-term safety and efficacy of hypofractionated stereotactic photon radiotherapy with 5 five fractions at 10Gy each in patients with centrally located choroidal melanoma. Materials and MethodsNinety-one patients with centrally located choroidal melanoma were treated stereotactically at a linear accelerator with 6MV photon beams with 5 fractions at 10Gy each. Examinations were performed at baseline and every 3months in the first 2years, then every 6months until 5years and yearly thereafter. Median follow-up was 37.8months (IQR 19.2–49.9). They included visual acuity assessment, routine ophthalmological examinations with fundoscopy, echography for measurement of tumor dimensions, medical examinations and, if necessary, fluorescein angiography. ResultsInitial tumor base diameters, height and volume were 11.20mm (IQR 9.10–13.70), 9.80mm (IQR 7.80–11.70), 4.53mm (IQR 3.33–6.43) and 253.8mm3 (IQR 127.5–477.0).Local tumor control and eye retention rates were 97.7% and 86.4% after 5years, respectively. Eight patients developed metastatic disease and 3 of them died due to metastatic disease during the follow-up period. Median visual acuity decreased from 0.67 initially to 0.05 at the last individual follow-up (p<0.001).The most common toxicities (any grade) were radiation retinopathy (n=39), optic neuropathy (n=32), radiogenic cataract (n=21), neovascular glaucoma (n=15) and dry eye syndrome (n=10). The 5year probabilities to remain free of these side effects (any grade) were 26.0%, 45.4%, 55.4%, 72.6% and 80.5%, respectively. The most important prognostic factors for toxicities were the largest tumor base diameter, tumor height and tumor distance to the optic disk. ConclusionHypofractionated stereotactic photon radiotherapy with a total dose of 50Gy delivered in 5 fractions is a highly effective treatment option in patients with centrally located choroidal melanoma and has a moderate toxicity profile.