Surgical Treatment of Giant Nonfunctioning Pituitary Adenomas

Abstract

Purpose: Giant pituitary adenomas, defined as those measuring at least 4 cm in maximum diameter, are a therapeutic challenge. The introduction in recent years of radiosurgery and the improvement of skull base techniques have increased the therapeutic choices in the treatment of giant pituitary adenomas. We report our experience in a large and consecutive series of patients with giant adenoma. Method: Between 1990 and 2006, 73 patients with a giant nonfunctioning pituitary adenoma (NFPA) underwent surgery in our department. Mean age at surgery was 51.8 ± 1.5 years (range, 24 to 81 yrs); there were 50 men (68.5%) and 23 women (31.5%). Preoperative visual impairment (visual field and/or visual acuity) was present in 66 patients (90.4%), cranial nerve palsy (3rd and/or 6th) in 5 patients (6.8%), hydrocephalus and mental change in 3 patients (4.1%), and nasal obstruction in 2 (2.7%). The mean maximum diameter, measured in all cases on preoperative MRI, was 46.3 ± 0.7 mm (range, 40 to 66). Results: As a whole, 86 surgical procedures were performed. Sixty-three approaches (73.3%) were trans-sphenoidal and 23 (26.7%) were transcranial: 9 were standard frontopterional or subfrontal approaches, and 14 were skull base approaches (7 fronto-orbitozygomatic and 7 enlarged subfrontal). Visual improvement occurred in 47 of the 64 patients with preoperative defect who could be evaluated after surgery (73.4%). Radical tumor excision, valued as absence of residual tumor on postoperative MRI performed 2 to 6 months after surgery, was obtained in 14 patients (19.2%). Adjuvant radiation therapies (gamma knife radiosurgery or fractionated radiotherapy) led to a control of recurrence-free survival of 89.6% at 5 years (95% confidence interval, 75.5 to 100%), while patients who did not receive radiation therapy had a significantly lower recurrence-free survival at 5 years (52.4%; 95% confidence interval, 28.5 to 76.2%). Radiation therapy had a protective role against tumor growth (p < 0.01 by the log-rank test). Conclusion: Maximal surgical removal of giant adenomas through the trans-sphenoidal and/or transcranial approaches, aiming to relieve compression of the optic pathway and reduce tumor volume as much as possible, offers the best chance to control the tumor when followed by adjuvant radiation therapies.