15 YEARS EXPERIENCE WITH HELIUM ION RADIOTHERAPY FOR UVEAL MELANOMA

Purpose: To review the long-term experience of helium ion therapy as a therapeutic alternative to enucleation for uveal melanoma, particular ly with respect to survival, local control, and morbidity. Methods and Materials: 347 patients with uveal melanoma were treated with heluim ion RT from 1978-1992. A nonrandomized dose-searching study was undert aken, with doses progressively reduced from 80 GyE in five fractions t o 48 GyE in four fractions, given in 3-15 days, mean of 7 days. Result s: Local control was achieved in 96% of patients, with no difference i n the rate of local control being seen at 80, 70, 60, or 50 GyE in fiv e fractions. At the lowest dose level of 48 GyE in four fractions, the local control rate fell to 87%. Fifteen of 347 patients (4%) had loca l regrowth in the eye requiring enucleation (12 patients), laser (1 pa tient) or reirradiation (2 patients). The time of appearance of local regrowth ranged from 4 months to 5 years posttreatment, with 85% occur ring within 3 years. Of the 347 patients, 208 are alive as of May 1, 1 997. The median follow up of all patients is 8.5 years, range 1-17 yea rs. Kaplan-Maier (K-M) survival is 80% at 5 years, 76% at 10 years, an d 72% at 15 years posttreatment. Patients with tumors not involving th e ciliary body have a 15-year K-M survival of 80%. The results for pat ients whose tumors involved the ciliary body are poor, with a 15-year K-M survival of 43%. Seventy-five percent of patients with tumors at l east 3.0 mm from the fovea and optic nerve, and initial ultrasound hei ght less than 6.0 mm, retained vision of 20/200 or better posttreatmen t. Patients with tumors larger than 6 mm in thickness, or with tumors lying close to the optic nerve or fovea, have a reduced chance of reta ining useful vision. The enucleation rate is 19%, 3% for local failure and 16% because of complications of the helium RT, particularly neova scular glaucoma, which occurred in 35% of patients. Conclusions: Local control and retention of the eye are excellent. Complications of ther apy reduce vision and eye preservation. Twenty-four percent of patient s manifested distant metastases 6 to 146 months posttreatment, mean of 43 months, median of 36 months. Late-appearing distant metastases do not appear to be caused by persistent tumor in the eye. The risk of me tastases is high for patients with tumors greater than 7 mm in initial ultrasound height (37%), anterior tumors involving the ciliary body ( 47%), and in those with local failure (53%). Patients with tumors not involving the ciliary body and initial dimensions less than 10 mm had only an 8% chance of death from melanoma. A search for effective adjuv ant therapy is needed for patients at high risk of metastases (large t umors, ciliary body involved, local regrowth in eye). (C) 1997 Elsevie r Science Inc.