Beyond Gross Total and Subtotal: Does Volumetric Resection Matter in Nonfunctioning Pituitary Macroadenomas? Joshua D. Hughes 1 , Kelly Koeller 2 , Lorenzo Rinaldo 1 , Dana Erickson 3 , Irina Bancos 3 , Fredric B. Meyer 1 , John Atkinson 1 , Jamie J. Van Gompel 1 - INTRODUCTION: No study has volumetrically examined resection degree and recurrence in pituitary macro- adenoma (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 1998e2008 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 preopera- tively 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 (20e85). Forty-one (53%) had no tumor recurrence at a median of 113 (48e203) months. Thirty-seven (47%) patients had tumor recurrence with a median time of 55 (9e176) months. On univariate analysis, increasing age, decreasing preoperative and postoperative volumes, and increasing EOR were statisti- cally significant for decreasing the risk of recurrence or treated recurrence. On multivariate analysis, only age and EOR remained significant. Receiver operating character- istic showed EOR <86% was associated with PMA regrowth. Kaplan-Meier analysis demonstrated a statisti- cally 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. INTRODUCTION T he traditional goals of surgery in pituitary macroadenoma (PMA) are to decompress visual structures and, if appli- cable, preserve pituitary function; gross total resection (GTR) is a variable objective depending on the surrounding structures involved by the tumor. Studies in PMA consistently show that patients with GTR have lower recurrence rates compared with subtotal resection (STR). 1-6 Unlike the category of GTR, STR includes a wide range of tumor residual. While studies using volumetric magnetic resonance imaging analysis have shown that the degree of STR is pertinent in glioma, 7-9 no studies have evaluated PMA with similar methodology. This is important as there are PMAs that cannot be resected totally and it is un- known whether these patients would benefit from more tumor resection past the traditional goal of tumor debulking primarily to preserve vision. Therefore we assessed whether volumetric anal- ysis of tumor resection impacted tumor recurrence and retreat- ment in a cohort of patients with nonfunctioning PMA >2 cm. METHODS Following approval by our Institutional Review Board, electronic records of patients with null cell or nonsecreting PMA 2 cm Key words - Extent of resection - Pituitary macroadenoma - Volume Abbreviations and Acronyms EOR: Extent of resection GTR: Gross total resection KSG: Knosp-Steiner grade MRI: Magnetic resonance imaging PMA: Pituitary macroadenoma ROC: Receiver operating characteristic STR: Subtotal resection From the Departments of 1 Neurologic Surgery, 2 Radiology, and 3 Endocrinology, Metabolism and Nutrition, Mayo Clinic, Rochester, Minnesota, USA To whom correspondence should be addressed: Jamie J. Van Gompel, M.D. [E-mail: vangompel.jamie@mayo.edu] Citation: World Neurosurg. (2018). https://doi.org/10.1016/j.wneu.2018.05.077 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2018 Elsevier Inc. All rights reserved. WORLD NEUROSURGERY -: ---, - 2018 www.WORLDNEUROSURGERY.org e1 Original Article