Long-term results of stereotactic proton beam radiotherapy for acoustic neuromas.

Abstract

A retrospective study evaluating the role of hypofractionated stereotactic proton beam therapy for acoustic neuromas. The data of 51 patients treated with hypofractionation (3 fractions) and followed up for a minimum of 2 years, were analyzed. Mean dose prescribed to ICRU reference point (isocenter) was 26 cobalt gray equivalent (CGyE) in 3 fractions. Mean minimum tumor dose was 21.4 CGyE/3. Cranial nerve functions were evaluated clinically. Serial MR Scans were used to evaluate local control. With a mean clinical and radiological follow-up of 72 and 60 months respectively, the 5-year results showed a 98% local control, with a hearing preservation of 42%, a facial nerve preservation of 90.5% and a trigeminal nerve preservation of 93%. For those patients harboring large acoustic neuromas that are inoperable, hypofractionated stereotactic proton beam offers long-term control with minimal side-effects.