Early resection of low-grade gliomas brings better survival rate than watchful waiting

by Bruce Sylvester – taken from the Journal of the American Medical Association (JAMA) – Researchers comparing methods for treating low-grade gliomas have found early surgical resection produced  better overall survival than biopsy and watchful waiting. The findings were published on Oct. 25, 2012 in JAMA.

“Due to diffuse brain infiltration, low-grade gliomas are usually not considered surgically curable,” said author and investigator Asgeir S. Jakola, MD, St. Olavs University Hospital, Trondheim, Norway, “In fact, the effect of surgery on survival remains unclear because current evidence relies on uncontrolled surgical series alone. Due to lack of better evidence, management of suspected low-grade gliomas has remained one of the major controversies in neuro-oncology and treatment strategies often differ considerably between neurosurgical centres,” he added.

The study included patients with low-grade gliomas at 2 Norwegian university hospitals. The hospitals  each used different surgical treatment strategies — diagnostic biopsies followed by a “wait and scan” approach in one hospital and early resection in the other hospital

The investigators evaluated histopathology specimens from all adult patients diagnosed with low-grade gliomas from 1998 through 2009, in a blinded histopathological review to ensure uniform classification and inclusion. Follow-up ended April 2011.

They identified 153 patients with diffuse low-grade gliomas (91% of screened cohort) and included them in the study, 66 (43%) from the hospital favoring biopsy and watchful waiting and 87 (57%) from the center favoring early resection.

The researchers noted large differences in treatment strategies; biopsy and subsequent watchful waiting was the first strategy used in 47 (71%) of low-grade gliomas patients treated at the center favoring biopsy and watchful waiting, compared with 12 (14%)  thus treated at the center favoring early resection.

Median follow-up was 7 years at the center favoring biopsy and watchful waiting, and 7.1 years at the center favoring early resection.

At end of follow-up, 34 patients (52%) from the center favoring biopsy and watchful waiting had died compared with 28 patients (32%) from the center favoring early resection. Overall survival was statistically significantly longer for patients treated at the center favoring early resection.

“The survival advantage increased with time,” the authors wrote. “While 1-year survival was 89% versus 89%, the expected 3-year survival was 70% versus 80%, expected 5-year survival was 60% versus 74%, and expected 7-year survival was 44% versus 68%. Median survival at the centre favouring biopsy was 5.9 years while median survival is not yet reached where initial resection was preferred.”

“In this comparative population-based study in patients with newly diagnosed low-grade gliomas, a survival benefit was observed for patients treated at a hospital advocating early resection as opposed to diagnostic biopsy and subsequent watchful waiting,” the authors concluded. “This significantly strengthens the data in support of early resection in newly diagnosed low-grade gliomas.”

In an accompanying editorial, James M. Markert, MD, University of Alabama at Birmingham, Birmingham, Alabama, wrote that “..although class 1evidence for surgical resection of low-grade gliomas remains lacking, National Comprehensive Cancer Center practice guidelines in oncology support maximal safe resection as a feasible first-line of treatment for low-grade gliomas. The majority of these studies, but not all ones published in the past 2 decades, support this approach as well. The study by Jakola et al adds further evidence for this approach. A follow-up study of their cohorts, allowing for more definitive measurement of survival and more rigorous assessment of complications, neurologic deterioration, and malignant degeneration, would be valuable.”