‘Postcode lottery’ sheds light on low-grade glioma strategy

By Eleanor McDermid, Senior medwireNews Reporter

Survival of adult patients with low-grade gliomas is better if they are admitted to a hospital that favors early resection, rather than one that opts for biopsy and watchful waiting, shows a study in JAMA.

"Such a potential difference in survival provides important data to help inform the complex question of whether to attempt aggressive [low-grade glioma] resection," writes James Markert (University of Alabama at Birmingham, USA) in an editorial accompanying the study.

However, he notes that the findings are not quite clear-cut; the 95% confidence intervals around the survival estimates overlapped, indicating that the difference between the two groups could have been a chance finding.

The findings are in line with prior studies, but previous research was hampered by strong treatment bias, with patients with a poor prognosis unlikely to be offered resection. The current study took advantage of two hospitals in Norway that had very different policies toward low-grade gliomas, with one favoring early resection and the other preferring biopsy and watchful waiting.

From 1998 through 2009, 66 patients were seen at the hospital that favored watchful waiting, 71% of whom initially underwent biopsy alone. A further 87 patients were seen at the hospital favoring early resection, and just 14% of these had an initial biopsy only. The two hospitals served adjacent geographic areas, so patients' initial treatment was determined to a large extent by where they lived.

During follow up lasting about 7 years, 52% of patients from the watchful-waiting hospital died, compared with 32% of those from the early-resection center. The median survival was 5.9 years for patients at the watchful-waiting center, whereas the median survival point for patients from the early-resection hospital had not been reached at the time of the study.

The survival advantage for patients at the early-resection versus watchful-waiting hospitals became apparent from 3 years after diagnosis, with expected survival rates of 80% versus 70%. This gap increased over time, with rates of 74% versus 60% at 5 years, and 68% versus 44% at 7 years.

Markert notes that more patients from the early-resection than watchful-waiting hospitals had oligodendrogliomas (19 vs 9%), which have naturally high survival rates. However, a post-hoc analysis of patients with astrocytomas, which have poorer survival rates, found that they also benefited from early resection.

The researchers, led by Asgeir Jakola (St Olavs University Hospital, Trondheim, Norway), stress that despite their findings, clinical judgment based on individual patient characteristics remains vital for determining management strategy of low-grade gliomas.

"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," they conclude.

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