STEREOTACTIC RADIOSURGERY FOR RECURRENT SURGICALLY TREATED ACROMEGALY- COMPARISON WITH FRACTIONATED RADIOTHERAPY

Object. The authors tested the assumption that gamma knife radiosurger y is more effective than fractionated radiotherapy for the treatment o f patients with acromegaly who have undergone unsuccessful resective s urgery. Untreated and uncured acromegaly causes illness and death. Acr omegalic patients in whom growth hormone and, particularly, insulin-li ke growth factor I are not normalized must undergo further treatment. Methods. After unsuccessful operations, 16 patients suffering from rec urrent and uncured acromegaly underwent stereotactic radiosurgery (25 Gy to the tumor margin, 50 Gy maximum), the outcome of which was compa red with the result obtained in 50 patients who received fractionated radiotherapy (40 Gy). The cumulative distribution functions of the two groups (Kaplan-Meier estimate) differed significantly (p < 0.0001 in the log-rank test of Mantel). The mean time to simultaneous normalizat ion of both parameters was 1.4 years in the group treated with the gam ma knife and 7.1 years in the group treated with fractionated radiothe rapy. Conclusions. The authors suggest the use of stereotactic radiosu rgery as the preferred treatment for recurrent acromegaly resulting fr om unsuccessfully resected tumors.