Proton Therapy for Uveal Melanoma in 43 Juvenile Patients

Abstract

To examine the metastatic and survival rates, eye retention probability, and the visual outcomes of juvenile patients after proton beam radiotherapy (PBRT) for uveal melanoma (UM). Retrospective case-factor matched control study. Forty-three patients younger than 21 years treated with PBRT for UM were compared with 129 matched adult control patients. Information on patient demographics and clinical characteristics were recorded before and after treatment from patients' files. The control group was composed of adult patients (>21 years) matched for tumor size (largest tumor diameter, ±2 mm; height, ±2 mm) and anterior margin location (iris, ciliary body, pre-equatorial or postequatorial choroid). For each juvenile patient, 3 adults were selected. Comparing outcomes of juvenile and adult patients in terms of metastatic and eye retention rates using the log-rank statistic, relative survival using the Hakulinen method, as well as their visual outcomes. Forty-three juvenile and 129 control cases were reviewed. The metastatic rate at 10 years was significantly lower in juvenile UM patients than in adult controls (11% vs. 34%; P <0.01), with an associated relative survival rate of 93% versus 65% (P= 0.02). Six juvenile patients (14%) demonstrated metastases. One patient underwent enucleation because of a presumed local tumor recurrence and 4 additional patients underwent enucleation because of complications (9.3%). In the adult control group, 27% (n= 35) of matched patients demonstrated metastases, there were 2 cases of local recurrence, and 16% (n= 21) underwent enucleation because of complications. A visual acuity of more than 0.10 was maintained in most cases, without any significant differences before or after treatment observed between both groups. After PBRT, metastatic and survival rates are significantly better for juvenile than for adult patients with UM. Clinically, juvenile and adult eyes react similarly to PBRT, with patients having a comparable eye retention probability and maintaining a useful level of vision in most cases. This is the largest case-control study of proton therapy in juvenile eyes to date and further validates PBRT as an appropriate conservative treatment for UM in patients younger than 21 years.