Carbon-ion radiotherapy for locally advanced or unfavorably located choroidal melanoma: a Phase I/II dose-escalation study.

Purpose: To evaluate the applicability of carbon ion beams for the treatment of choroidal melanoma with regard to normal tissue morbidity and local tumor control.

Methods And Materials: Between January 2001 and February 2006, 59 patients with locally advanced or unfavorably located choroidal melanoma were enrolled in a Phase I/II clinical trial of carbon-ion radiotherapy at the National Institute of Radiologic Sciences. The primary endpoint of this study was normal tissue morbidity, and secondary endpoints were local tumor control and patient survival. Of the 59 subjects enrolled, 57 were followed >6 months and analyzed.

Results: Twenty-three patients (40%) developed neovascular glaucoma, and three underwent enucleation for eye pain due to elevated intraocular pressure. Incidence of neovascular glaucoma was dependent on tumor size and site. Five patients had died at analysis, three of distant metastasis and two of concurrent disease. All but one patient, who developed marginal recurrence, were controlled locally. Six patients developed distant metastasis, five in the liver and one in the lung. Three-year overall survival, disease-free survival, and local control rates were 88.2%, 84.8%, and 97.4%, respectively. No apparent dose-response relationship was observed in either tumor control or normal tissue morbidity at the dose range applied.

Conclusion: Carbon-ion radiotherapy can be applied to choroidal melanoma with an acceptable morbidity and sufficient antitumor effect, even with tumors of unfavorable size or site.