Beyond Gross Total and Subtotal: Does Volumetric Resection Matter in Nonfunctioning Pituitary Macroadenomas?

Introduction: No study has volumetrically examined resection degree and recurrence in pituitary macroadenoma (PMA). We analyzed the impact of volumetric tumor resection on prediction of tumor recurrence and retreatment in a cohort of patients with nonfunctioning PMA ≥2 cm. Methods: Records were reviewed from 1998–2008 for patients with null cell or nonsecreting PMA ≥2 cm. Inclusion criteria were surgically resected PMA and ≥4 years’ follow-up or recurrence before 4 years. Seventy-eight patients were found. PMA tissue volume preoperatively and postoperatively was quantified by a board-certified neuroradiologist. Extent of resection (EOR) was calculated. The primary end point was tumor recurrence with a secondary end point of treated tumor recurrence. Result: Median age was 58 (20–85). Forty-one (53%) had no tumor recurrence at a median of 113 (48–203) months. Thirty-seven (47%) patients had tumor recurrence with a median time of 55 (9–176) months. On univariate analysis, increasing age, decreasing preoperative and postoperative volumes, and increasing EOR were statistically significant for decreasing the risk of recurrence or treated recurrence. On multivariate analysis, only age and EOR remained significant. Receiver operating characteristic showed EOR <86% was associated with PMA regrowth. Kaplan-Meier analysis demonstrated a statistically significant difference for recurrence comparing groups by EOR ≥86% or <85%. Conclusions: We found younger age and increasing EOR are significant predictors of tumor regrowth and retreatment. These results indicate EOR assessment may have a role in large PMA. Further study with volumetric analysis is needed in a larger cohort of patients.