Proton therapy for uveal melanoma in 43 juvenile patients: long-term results

Abstract

Purpose: 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).

Design: Retrospective case-factor matched control study.

Participants and controls: Forty-three patients younger than 21 years treated with PBRT for UM were compared with 129 matched adult control patients.

Methods: 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.

Main outcome measures: 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.

Results: 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.

Conclusions: 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.