Long-term follow-up of patients with pituitary macroadenomas after postoperative radiation therapy: analysis of tumor control and functional outcome.

Purpose: Evaluation of long-term tumor control, normalization of hormonal hypersecretion, including incidence and time course of pituitary dysfunction following postoperative radiotherapy of pituitary macroadenomas.
Patients and Methods: In a retrospective study, the data of 87 patients with pituitary macroadenomas (61 non-secreting adenomas, 26 secreting adenomas) treated between 1984 and 1994 were analyzed. All patients underwent surgery and received postoperative external-beam radiotherapy with a mean dose of 50.4 Gy (range 46-54 Gy).
Results: After a follow-up of 15 years the local tumor control rate achieved was 93.0% for non-secreting adenomas and 100% for secreting adenomas, respectively. Normalization of endocrine hypersecretion was noted in 24 of 26 patients (92%). Detailed endocrinological follow-up data were analyzed by an experienced endocrinologist in 77 patients. After a median follow-up of 10.54 years (mean 10.22; range 1.39-20.75 years), in 75 of 77 patients (97%) a hypopituitarism was observed (partial hypopituitarism, n = 28 [36%], panhypopituitarism, n = 47 [61%]), and 68 out of 77 patients (88%) showed evidence of radiotherapy-induced pituitary disorders. The somatotropic function was most commonly affected, followed by gonadal, thyroid and adrenal function. The gonadal axis showed to be the first to be disturbed. 67 patients (87%) required a hormone replacement therapy.
Conclusion: Radiotherapy after pituitary surgery is highly effective in reducing hormonal hypersecretion and preventing recurrences of pituitary adenomas. However, pituitary insufficiencies are commonly observed after radiotherapy requiring a close follow-up to ensure timely diagnosis of pituitary dysfunction and an early inception of hormone replacement therapy.