Long-term outcomes of radiotherapy for pituitary adenomas

PURPOSE: To evaluate long-term local control and toxicity for pituitary adenomas treated with fractionated radiotherapy (RT). METHODS AND MATERIALS: The records of 100 patients with pituitary adenomas treated between 1983 and 2003 were retrospectively reviewed. Thirty-one patients had hormone-secreting tumors; 69 patients were treated with surgery and postoperative RT. Median follow-up was 6.7 years (range, 0.6-20.2 years) for all patients and 6.2 years (range, 2-20.2 years) for living patients. The mean dose delivered was 45 Gy (range, 43-50.4 Gy). RESULTS: The 10-year actuarial local control rates for nonsecreting and secreting adenomas were 98% and 73%, respectively (p = 0.0015). Actuarial 10-year cause-specific survival (CSS) rates were 95% and 88%, and overall survival rates were 66% and 79% for nonsecreting and secreting adenomas, respectively. Involvement of the sphenoid sinus was found to be significantly associated with decreased 10-year CSS (p = 0.0453). When compared with the two- or three-field techniques, stereotactic RT was associated with improved CSS (p = 0.0775). CSS was not significantly associated with hormone excretion, extent of surgery, or whether RT was administrated postoperatively or for salvage after a postsurgical recurrence. New cases of hypopituitarism occurred in 35 patients. One patient experienced vision loss, and one patient developed a post-treatment glioma. CONCLUSIONS: This is one of the most mature series in the literature that documents excellent results with fractionated RT for pituitary adenoma. We recommend 45 Gy at 1.8 Gy per fraction using stereotactic noncoplanar fields.