Purpose: External radiation therapy for non functioning pituitary adenomas is clearly indicated in inoperable patients, after incomplete transsphenoidal microsurgery and in case of tumor progression. This retrospective analysis gives results and toxicity following surgery and postoperative radiotherapy of non-functioning pituitary adenomas.
Patients and methods: Between 1983 and 1990, 50 patients with non-functioning pituitary adenomas received combined treatment at our institutions. Surgical approaches were transsphenoidal (61%), transcranial (24%) or a combination of both (15%) in short intervals. All 50 patients received a full-dose radiotherapy with single fractions between 1.9 and 2.1 Gy (median 1.9 Gy) and total doses between 46 and 63 Gy (median 48 Gy). Field sizes ranged between 20 and 72 cm2 (median 30 cm2). Endpoints of this study were: progression-free survival, late effects of brain, optic nerve and intracranial vessels, visual impairment and hypothalamic-pituitary dysfunction. Median follow-up was 54 months.
Results: Forty-seven of the 50 patients remained progression-free. Patients over age 60 years progressed more frequently (3/17) as compared to younger patients (0/33, p = 0.034). Following radiotherapy vision improved in 8 patients (16%), 14 patients (28%) experienced a visual impairment between 10% and 60% (according to the grading system of the German Ophthalmologic Society). In multivariate analysis no influence of age (p = 0.097) or biologically effective dose (BED) (p = 0.11) was seen on visual impairment. Three patients (6%) experienced late effects with optic neuropathy in 2 cases and temporal lobe necrosis in 1 case. Only the BED had a significant impact on late effects (p = 0.0094). Adrenal, thyroid and gonadal function abnormalities were present in 58%, 66% and 96% of the patients at last follow-up, respectively.
Conclusions: Radiotherapy after incomplete transsphenoidal or transcranial surgery of non-functioning pituitary adenoma is an effective treatment. Future perspectives must include the better defining of high-risk patients and the reduction of late morbidity.