Adjuvant Radiation Therapy Compared with Observation Alone for Postoperative Residual Nonfunctional Pituitary Adenomas

OBJECTIVE: The management of residual nonfunctional pituitary tumors after surgical resection remains controversial. In this study, we compared the prognosis of postoperative radiation therapy and observation only in patients with residual nonfunctional pituitary adenoma and reviewed the long-term complications after radiation therapy. METHODS: We retrospectively analyzed 90 patients who underwent surgery for nonfunctional pituitary adenomas from January 2008 to April 2012. Residual tumors were classified by size, location, and pathologic staining. Tumor progression was defined as volume progression >= 15% with or without clinical symptoms. Postoperative radiation therapy was performed <1 year after the last surgery. We compared the progression and 3-year and 5-year progression-free survival between the observation group and postoperative radiation therapy group. Postradiation complications including hypopituitarism, diabetes insipidus, deterioration in visual field or acuity, cranial nerve palsy, and hydrocephalus were also analyzed. RESULTS: More of the patients who received postoperative radiation therapy had a tumor progression-free survival of >= 3 years than did those who did not receive postoperative radiation therapy. Postoperative radiation therapy was significantly beneficial for the patients with a tumor size >= 3 cm or with tumors in the cavernous sinus. The most frequent complication after radiation therapy was hypopituitarism and a few cases had third cranial nerve palsy; however, there were no significant relationships with radiation therapy. CONCLUSIONS: In this study, immediate radiation therapy after tumor resection was an effective and relatively safe treatment for residual or progressive nonfunctional pituitary adenomas. Moreover, the long-term complications of radiation therapy were mild.