A total of 112 patients with the diagnosis of nonfunctional pituitary adenoma received radiation therapy at the University of Pittsburgh between 1964 and 1987. Postoperative radiation therapy was administered in 87 patients. Actuarial progression-free survival (tumor control) at 5, 10, 15, and 20 years was 97%, 89%, 87%, and 7670, respectively. Radiation prescribed to the 95% isodose ranged from 35.72 Gy to 62.32 Gy. Multivariate analysis showed decreased tumor control to be significantly associated with increasing field size (P = -036). No improvement in tumor control could be detected with increasing total radiation dose or nominal standard dose (NSD). One patient developed optic neuropathy and another developed a glioblastoma after doses in both patients of 4750 cCy in 25 fractions. External beam radiotherapy for nonfunctional pituitary adenomas was found to be effective and safe when doses less than 4750 cCy in 25 fractions were used. Cancer 63:2409-2414. 1989.
ITUITARY TUMORS that do not secrete detectable pi-P tuitary hormones are considered nonfunctional pituitary adenomas. These tumors also are called undifferentiated, null cell, nonsecretory, or chromophobe adenomas of the pituitary, although the term "chromophobe adenoma" is less useful.' At the time of presentation, these tumors usually have extended beyond the normal confines of the pituitary gland into the suprasellar region most commonly and have sometimes invaded the sphenoid sinus or the cavernous sinus. Because of tumor extension and invasion, control by surgery alone is difficult. Radiation therapy has been used extensively and with success as either primary treatment or postoperative treatment to prevent recurrence of these turn or^.^-^ A review of the patients irradiated at the University of Pittsburgh for nonfunctional pituitary adenomas was undertaken to try to identify factors related to tumor control and complications.