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 pituitary adenoma, who were first treated between 1969 and 1994 and had been followed for more than 2 years (median, 8.2 years) Of these patients, 86 had received postoperative radiotherapy, and 5 had received radiotherapy alone. The median total dose was 51 Gy, Clinical symptoms related to mass effects or endocrine hypersecretion were assessed. The efficacy of radiotherapy was evaluated before treatment and during the follow-up period (1-14 years; median, 3 Sears) by estimating tumor size on computed tomography or magnetic resonance imaging in 56 patients, as well as by endocrine testing in the 22 patients 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 such symptoms due to nonsecreting adenomas and secreting adenomas, respectively. 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 years 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 secreting adenomas), Three patients with secreting adenomas (2 with prolactinoma and 1 with Cushing's disease) showed a mismatch between reduction in tumor size and normalization of endocrine hypersecretion. The 10-year local control rates were 98%, 85%, 83%, and 67% for nonsecreting adenoma, growth-hormone-secreting adenoma, prolactinoma, and Cushing's disease, respectively. Univariate analyses showed that disease type and radiation field size were significant prognostic factors. Brain necrosis occurred in 1 patient who received 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 tumor size and endocrine hypersecretion may be mismatched in some secreting adenomas, (C) 2000 Elsevier Science Inc.