Practice Update | Onology

EDITOR’S PICKS 9

Surgical resection vs watchful waiting in low-grade glioma Annals of Oncology Take-home message • The authors of this population-based parallel cohort study compared clinical outcomes in patients with infiltrating low-grade gliomas treated with resection and those undergoing watchful waiting. Region A favored watchful waiting; region B favored early resection. The primary endpoint was overall survival. In total, 153 patients were involved (66 from region A and 87 from region B); 94 underwent early resection (19 from region A and 75 from region B). Overall survival was 5.8 years in region A and 14.4 years in region B. • Overall survival was associated with early surgical resection, even after adjustment for molecular markers (P = 0.001).

Abstract BACKGROUND Infiltrating low-grade gliomas (LGG; WHO grade 2) typically present with seizures in young adults. LGGs grow continuously and usu- ally transform to higher grade of malignancy, eventually causing progressive disability and premature death. The effect of up-front surgery has been controversial and the impact of molec- ular biology on the effect of surgery is unknown. We now present long-term results of upfront sur- gical resection compared to watchful waiting in light of recently established molecular markers. This report provides reasonably compelling evidence, and additional evidence to other more conventional retrospective series, that early surgery results in a better prognosis in this population, perhaps by delaying malignant transformation. MATERIAL AND METHODS Population-based paral- lel cohorts were followed from two Norwegian university hospitals with different surgical treat- ment strategies and defined geographical catchment regions. In region A watchful waiting was favored while early resection was favored in region B. Thus, the treatment strategy in indi- vidual patients depended on their residential address. The inclusion criteria were histopatho- logical diagnosis of supratentorial LGG from 1998 through 2009 in patients 18 years or older. Follow-up ended 1st January 2016. Mak- ing regional comparisons, the primary end-point was overall survival. RESULTS 153 patients (66 from region A, 87 from region B) were included. Early resection was carried out in 19 (29%) patients in region A com- pared to 75 (86%) patients in region B. Overall survival was 5.8 years (95% CI 4.5–7.2) in region A compared to 14.4 years (95% CI 10.4–18.5) in region B (P<0.01). The effect of surgical strategy remained after adjustment for molecular mark- ers (P=0.001).

CONCLUSION In parallel population based cohorts of LGGs, early surgical resection resulted in a clinical relevant survival benefit. The effect on survival persisted after adjustment for molecu- lar markers. COMMENT By Gene H. Barnett MD, MBA,FAANS, FACS

Surgical resection versus watchful waiting in low-grade gliomas. Ann Oncol 2017 May 05;[EPub Ahead of Print], AS Jakola, AJ Skjuls- vik, KS Myrmel, et al.

I n this retrospective review from Norway, the authors compared the results of two different hospitals’ (widely separated geographically) strategies for management of newly diagnosed low-grade gliomas. In one, early surgery was favored; in the other, biopsy and watchful waiting was the preferred approach. The overall survival in the early-surgery group was about 8 years longer than in the observation group (14.4 vs 5.8 years), and this difference was not explained by histological, molecular, or other characteristics of the group. As a randomized trial addressing the question of which approach is best is unlikely to ever be done, this report provides reasonably compelling evidence, and additional evidence to other more conventional retrospec- tive series, that early surgery results in a better prognosis in this population, perhaps by delaying malignant transformation.

Dr Barnett is Professor and Director, Rose Ella Burkhardt Brain Tumor & Neuro-Oncology Center, Cleveland Clinic Neurological Institute, The Cleveland Clinic in Ohio.

VOL. 1 • NO. 2 • 2017