REASSESSMENT OF THE ROLE OF RADIATION-THERAPY IN THE TREATMENT OF ENDOCRINE-INACTIVE PITUITARY MACROADENOMAS

OBJECTIVE: This prospective clinical trial was undertaken to assess th e rate of tumor recurrence in patients with endocrine-inactive pituita ry macroadenomas who underwent gross total surgical resection of their tumors and did not receive adjuvant radiotherapy. METHODS: Between De cember 1987 and July 1994, 45 patients with endocrine-inactive pituita ry macroadenomas underwent transsphenoidal surgery. In 38 (84%) of the se patients, gross total surgical resection was achieved and was confi rmed by postoperative magnetic resonance imaging (n = 37) or computed tomography (n = 1). After receiving counseling from the neurosurgeon c oncerning the risks and benefits of radiation therapy, 32 of the 38 pa tients elected not to receive adjuvant radiotherapy. Patients were fol lowed through March 1998 with radiographic imaging obtained every 6 mo nths for the first 2 years, annually for postoperative Years 3 and 4, and then every 2 to 3 years thereafter. The study end point was define d as radiographic tumor recurrence or patient death. RESULTS: The mean follow-up duration for the study group was 5.5 years. During that tim e, 2 of 32 (6%) patients developed recurrence, at 18 and 24 months, re spectively, after initial surgery. Both were successfully treated usin g radiation therapy, with one requiring additional surgery. Three addi tional patients died as a result of unrelated causes 9, 12, and 49 mon ths, respectively, after initial surgery. Immunocytochemical analysis revealed 66% of the tumors to be weak gonadotroph cell adenomas, 22% t o be null cell adenomas, 9% to be silent prolactinomas, and 3% to be s ilent corticotroph cell adenomas. CONCLUSION: This study demonstrates a 6% 5-year recurrence rate in patients with endocrine-inactive pituit ary macroadenomas treated using gross total surgical resection alone. Reserving radiation therapy for the infrequent patient with recurrence and sparing the majority of patients the associated risks inherent in its use seems reasonable.