Factors predicting relapse of nonfunctioning pituitary macroadenomas after neurosurgery: a study of 142 patients

CONTEXT: Adequate postoperative management of nonfunctioning pituitary macroadenomas (NFMAs) remains a challenge for the clinician. OBJECTIVE: To identify predictive factors of NFMA relapse after initial surgery. PATIENTS AND METHODS: This retrospective study included 142 patients operated for an NFMA in two academic centers (CHU Bicêtre in France and UCL St Luc in Belgium). The rate of tumor relapse, defined as recurrence after total surgical resection or regrowth of a surgical remnant, as well as predictive factors was analyzed. RESULTS: During a mean follow-up of 6.9 years, 10 out of 42 patients (24%) who had complete macroscopic resection of their tumor had recurrence, and 47 out of 100 patients (47%) with a surgical remnant experienced regrowth. The overall relapse rates were 25, 43, and 61% at 5, 10, and 15 years respectively. Invasion of the cavernous sinus, absence of immediate radiotherapy after the first neurosurgery, and immunohistochemical features of the tumor (mainly positive immunostaining for several hormones or for hormones other than gonadotropins) were independent risk factors for tumor relapse. Incomplete excision was only associated with relapse when invasion was withdrawn from the analysis, suggesting that these two factors are closely linked. CONCLUSION: NFMAs frequently recur/regrow after initial surgery, particularly when tumor is invasive, precluding complete removal. Immunohistochemical features such as positive immunostaining for several hormones or for hormones other than gonadotropins could help to predict undesirable outcomes.