Maximizing local tumor control and survival after proton beam radiotherapyof uveal melanoma

Purpose: This study reports local tumor control and survival after proton b eam radiotherapy (PBRT) of uveal melanoma. It identifies the risk factors f or local tumor-control failure and for ocular tumor-related death. It prese nts the improvements implemented to increase the rate of local tumor contro l, and compares the survival rate of patients with locally controlled tumor s to those of patients who had to receive a second treatment. Patients and Methods: We have treated 2,435 uveal melanomas with PBRT betwe en March 1984 and December 1998. Data were analyzed as of September 1999. P atients' age ranged from 9 to 89 years; there were 1,188 men and 1,247 wome n. The largest tumor diameter ranged from 4 to 26 mm, and tumor thickness f rom 0.9 to 15.6 rum. Median follow-up time was 40 months. Results: Local tumor control probability at 5 years was improved from 90.6 +/- 1.7% for patients treated before 1988, to 96.3 +/- 0.6% for patients tr eated between 1989 and 1993, and became 98.9 +/- 0.6% for patients treated after 1993. Among 2,435 treated patients, 73 (3%) had to receive a second t reatment because of tumor regrowth. Cause-specific survival at 10 years was calculated to 72.6 +/- 1.9% for patients with controlled tumors compared t o 47.5 +/- 6.5% for those with recurrent tumors. Conclusion: Reduced safety margins, large ciliary body tumors, eyelids with in the treatment field, inadequate positioning of tantalum clips, and male gender were identified to be the main factors impairing local tumor control . The improvement of local tumor control rate after 1993 is attributed to c hanges implemented in the treatment procedure. Our data strongly support th at the rate of death by metastases is influenced by local tumor control fai lure: improvement of the local tumor control rate results in a better survi val rate. (C) 2001 Elsevier Science Inc.