Treatment of conjunctival lymphomas by beta-ray brachytherapy using a strontium-90-yttrium-90 applicator

We reviewed the outcome of the 10 patients (13 eyes) with localized, biopsy-proven, low-grade lymphoma of the conjunctiva treated at our Department between 1988 and 1997. All patients were treated by beta-ray brachytherapy using a bidirectional 90Sr-90Y ophthalmic applicator (Applicator SIA 2, Amersham plc). Total doses, prescribed at the surface of the applicator, varied between 40 Gy and 80 Gy. With a median follow-up of 78 months (range: 14 to 146 months), seven patients remained with no evidence of relapse (67.5% 10 year disease free survival). Local control was achieved in 10 out of 13 eyes (76.9%). Two of the three local relapses were marginal. One of these three patients also developed a metachronous lymphoma in the contralateral conjunctiva. These three patients underwent a second course of brachytherapy with 90Sr/90Y and remained free of second relapse 109, 68 and 33 months after salvage therapy. No cases of systemic relapse were observed. Late (LENT-SOMA) complications were of grade 2 in five eyes, of grade 3 in one eye and of grade 4 in one eye. Late complications of grade 2 or higher were observed in one out of five patients (20%) treated with doses lower or equal to 50 Gy and in six out of eight patients (75%) treated with doses higher than 50 Gy (P=0.086). Our data indicates that beta-ray brachytherapy was ultimately able to control most conjunctival lymphomas but carried a risk of late complications and marginal relapses that was possibly higher than the rates reported for other radiotherapy techniques.