The efficacy of conventional radiation therapy in the management of pituitary adenoma

Purpose: To evaluate the efficacy of conventional radiotherapy for reducing tumor size and endocrine hypersecretion of pituitary adenomas, Methods and Materials: We reviewed the records of 91 patients with pituitar y adenoma, who were first treated between 1969 and 1994 and had been follow ed for more than 2 years (median, 8.2 years.) Of these patients, 86 had rec eived postoperative radiotherapy, and 5 had received radiotherapy alone. Th e median total dose was 51 Gy, Clinical symptoms related to mass effects or endocrine hypersecretion were assessed. The efficacy of radiotherapy was e valuated before treatment and during the follow-up period (1-14 years; medi an, 3 Sears) by estimating tumor size on computed tomography or magnetic re sonance imaging in 56 patients, as well as by endocrine testing in the 22 p atients who had secreting adenomas, Local control rate, prognostic factors, and side effects were analyzed. Results: Mass-effect symptoms improved in 72% and 79% of patients who had s uch symptoms due to nonsecreting adenomas and secreting adenomas, respectiv ely. Symptoms of endocrine hypersecretion abated in 67% of patients who had such symptoms. Excessive hormone levels normalized in 74% of patients who showed endocrine hypersecretions. The greatest size reduction was seen 3 ye ars after the completion of radiotherapy (23% CR, 62% PR, 12% NC, and 3% PD in nonsecreting adenomas, and 32% CR, 36% PR, 27% NC, and 5% PD in secreti ng adenomas), Three patients with secreting adenomas (2 with prolactinoma a nd 1 with Gushing's disease) showed a mismatch between reduction in tumor s ize and normalization of endocrine hypersecretion. The 10-year local contro l rates were 98%, 85%, 83%, and 67% for nonsecreting adenoma, growth-hormon e-secreting adenoma, prolactinoma, and Gushing's disease, respectively. Uni variate analyses showed that disease type and radiation field size were sig nificant prognostic factors. Brain necrosis occurred in 1 patient who recei ved a 60-Gy dose of irradiation. Conclusion: We conclude that conventional external radiotherapy with 50 Gy is safe and sufficient to control pituitary adenoma, Careful observation is required in the management of secreting adenomas because the effects on tu mor size and endocrine hypersecretion may be mismatched in some secreting a denomas, (C) 2000 Elsevier Science Inc.