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There is general agreement that postoperative radiation therapy is beneficial for patients with subtotally resected pituitary adenomas. We have identified 41 such patients treated during a 20-year period who received postoperative irradiation for a pituitary adenoma. The usual dose was 5040 cGy in 28 fractions. The mean follow-up time was 10.3 years. On routine hematoxylin and eosin (H&E) staining, there were thirty-three chromophobe, seven eosinophilic, and one basophilic adenoma. Tissue blocks were stained for growth hormone (GH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), prolactin (PRL), and/or adrenocorticotropin (ACTH) using the peroxidase-antiperoxidase immunohistochemistry (IHC) method. Routine H&E staining was a poor predictor of the IHC stain. While most patients with a known clinical endocrine syndrome stained positive on IHC for the suspected offending hormone, many patients without a clinical syndrome also stained positive indicating the presence of hormonally occult adenomas in this locally invasive group. The IHC stain results were compared to clinical outcome. The presence of positive GH IHC staining decreased the 15-year progression-free survival (PFS) from 100% to 64% compared to GH negative adenomas (p = 0.06). There was a trend toward decreased 15-year PFS in patients who did not stain for LH. Positive staining for prolactin, ACTH, or TSH had no influence on the progression-free survival. We conclude that additional prognostic information can be obtained in this subset of patients (by performing IHC analysis) that is not known by the clinical presentation or appearance on H&E stain.

A retrospective analysis was performed on the clinical course of all patients with pituitary adenomas treated at the Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University Medical Center, St. Louis, Missouri. Of 212 patients treated from April 1954 through December 1982, 70 were treated with radiotherapy alone (XRT), 121 began immediate post-operative XRT (2-6 weeks) and 20 received XRT following surgical failure. Several sub-groups of adenomas were identified and analyzed, including secreting versus non-secreting adenomas (33.0% secreting) and by clinical syndrome; 27% with amenorrhea/galactorrhea, 18.4% acromegalic, Cushing's disease in 6.1% and 3.3% with Nelson's syndrome. The median follow-up time from the data of diagnosis for those patients alive at the time of last follow-up was 11.9 years (range 3.0 to 30.0 years). Actuarial overall and disease-free survival was analyzed up to 25 years. The 10-year overall and disease-free survival was 77.8 and 75.3% for those patients treated with XRT alone, 86.4 and 87.2% for those treated with immediate post-operative XRT and 100.0 and 87.5% for those who were irradiated after surgical failure. Complications related directly to XRT occurred in only five patients. One patient had documented central nervous system radionecrosis, two had visual complications, and tumor necrosis with hemorrhage occurred in the other two patients. In conclusion, overall survival for all patients did not significantly differ from an age, sex and race matched population. Control of local disease was greater for those patients receiving surgery and post-operative XRT than for those receiving XRT only. XRT salvage of surgical failures was possible. Treatment with XRT results in a low complication rate.