Local Recurrence After Primary Proton Beam Therapy in Uveal Melanoma: Risk Factors, Retreatment Approaches, and Outcome

Abstract

To evaluate the risk factors, recurrence rates, retreatments, and long-term patient outcomes following proton beam therapy for uveal melanoma. Retrospective interventional case series. All patients treated with primary proton beam therapy for uveal melanoma at the oncology service at Charité-Berlin and Helmholtz-Zentrum-Berlin between May 1998 and December 2008 were reviewed for local recurrence. Of 982 patients, 982 eyes matched the inclusion criteria. The data were obtained from electronic health records, operative reports, discharge letters, and radiation planning. Comparisons of fundus photographs and ultrasound measurements were performed to assess the growth pattern of the tumor and to determine the success of retreatment, in the case that a globe-retaining therapy was undertaken. Of 982 patients, 35 patients (3.6%) developed local recurrence. The median follow-up was 60.7 months (6.0-170.4 months). Local control rate was 96.4% and the overall eye retention rate was 95.0% in this cohort. Local recurrence was correlated with a higher risk for metastasis and reduced survival. Largest tumor diameter was identified as the sole statistically significant risk factor for local recurrence (P = .00001). All globe-retaining retreatment approaches for local recurrence, including proton beam therapy, brachytherapy, and transpupillary thermotherapy used for recurrences at the tumor margins, showed good local tumor control and similar metastasis-free survivals. This study showed that each globe-retaining retreatment approach can result in satisfying local tumor control. In case of early detection of local recurrence, preservation of the globe can be warranted. Therefore, regularly performed follow-ups should be ensured.