Adrenocorticotropic hormone-producing pituitary tumors: 12-to 22-year follow-up after treatment with stereotactic radiosurgery

OBJECTIVE: To study retrospectively long-term outcomes of patients with adr enocorticotropic hormone-producing pituitary tumors that were treated with stereotactic Leksell gamma knife unit radiosurgery. METHODS: Eighty-nine patients aged 5 to 67 years were treated between 1976 and 1985. Eighteen patients aged 18 to 68 years (mean age, 41 yr) were foll owed in detail. Fifteen patients were women. None had previously received c onventional radiotherapy, but pituitary microsurgery had been performed in two patients, and one patient had had an adrenalectomy. In the remaining 15 patients, radiosurgery was the primary therapy. RESULTS: Sixty-four patients had one stereotactic treatment, and 25 patient s had two or more treatments. No complications were observed during treatme nt and the immediate follow-up period. At follow-up, 17 patients had died 1 to 20 years after the first treatment. No deaths were related to the treat ment. In our 18 patients, the follow-up time after the first radiosurgical treatment was 12 to 22 years (mean follow-up period, 17 yr). Urinary cortis ol levels gradually normalized in 83% of the patients. No recurrences were observed. Pituitary hormone insufficiencies developed in about two of every three patients and occurred even more than 10 years after treatment. Eight patients had transient hyperprolactinemia. The patients' vision and visual fields were unaffected, and none of them had signs of radiation-induced si de effects such as brain tumors or brain necrosis. CONCLUSION: Stereotactic radiosurgery is a safe and effective method in the treatment of patients with adrenocorticotropic hormone-producing pituitary tumors, and the effect of treatment is long-lasting. Stereotactic radiosur gery is mainly a complement to microsurgery because of its gradually appear ing effect and the occurrence of pituitary insufficiency. New pituitary def iciencies may be found more than 10 years after treatment.