In a comparison of surgical treatment strategies for low-grade gliomas, patients in Norway treated at a hospital that generally favored early surgical resection had better overall survival than patients treated at a hospital that favored diagnostic biopsy and watchful waiting, according to a study published in the Journal of the American Medical Association and presented at the Annual Meeting of the European Association of Neurosurgical Societies.
The study included patients 18 years or older with diffuse low-grade gliomas (World Health Organization grade 2) treated at two Norwegian university hospitals with different treatment strategies—diagnostic biopsies and watchful waiting vs early resections. “Both neurosurgical departments are exclusive providers in adjacent geographical regions with regional referral practices,” the authors noted. Thus, they explained, the treatment strategy for a given patient has depended on where the patient lives.
Following a blinded histopathologic review to ensure uniform classification and inclusion, 153 patients with diffuse low-grade gliomas (91% of the screened cohort) were identified and included in the study; 66 patients (43%) from the center favoring biopsy and watchful waiting and 87 patients (57%) from the center favoring early resection.
“There were large regional differences in treatment strategies,” the researchers reported, “as biopsy and subsequent watchful waiting was the initial strategy in 47 (71%) of [low-grade glioma] patients served by the center favoring biopsy and watchful waiting compared with only 12 (14%) served by the center favoring early resection (P < .001).” The researchers found “no significant differences in surgical complications (9% vs 8%; P = .82) or acquired deficits (18% vs 21%; P = .70) between centers. Later malignant transformation was more common when biopsy only was the favored initial management (56% vs 37%; P = .02).”
Overall survival was significantly longer for patients treated at the center favoring early resection, and the survival advantage increased with time. While 1-year survival rates were equal at 89%, the expected survival rates were 70% vs 80% at 3 years, 60% vs 74% at 5 years, and 44% vs 68% at 7 years. At the center favoring biopsy, median survival was 5.9 years, whereas at the center preferring initial resection, median survival had not been reached at the time of the report.
“Despite the clear survival advantage seen, clinical judgment is still necessary in individual patients with suspected [low-grade glioma] since results will depend on patient and disease characteristics together with surgical results in terms of resection grades and complication rates,” the authors stated. “Nevertheless, based on the observed regional survival difference in the present study, both involved centers now advocate early resections as the initial recommendation in most patients.” The researchers concluded that the survival benefit “significantly strengthens the data” supporting early resection in patients with newly diagnosed low-grade glioma.
In an accompanying editorial, James M. Markert, MD. of the University of Alabama at Birmingham, wrote that “although class I evidence for surgical resection of [low-grade glioma] remains lacking,” National Comprehensive Cancer Network practice guidelines in oncology support the use of maximal safe resection as feasible first-line treatment for low-grade glioma. He added that most, but not all, studies published in the past 2 decades “support this approach as well,” and the current study “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.” ■
Jakola AS, et al: JAMA 308:1881-1888, 2012.
Markert JM: JAMA 308:1918-19198, 2012.