Radiosurgery gains more focus after brain tumor resection
medwireNews: Postoperative stereotactic radiosurgery (SRS) is most suitable for the management of brain metastases when gross total resection is possible and lower volumes of radiation exposure is called for.
"[W]ith improvements in treatment for a variety of solid tumors, increased survival has begun to unmask significant neurocognitive side effects with [whole-brain radiation therapy] WBRT," write Jared Gans (University of Miami, Florida) and colleagues in Neurosurgery.
"It is important to understand the role of alternative treatment options, most prominently SRS, as an adjuvant to primary surgical resection for suitable metastatic intracranial lesions."
Researchers conducted a systematic literature review of 14 studies involving a total of 626 patients to assess the outcomes following surgical resection with adjuvant stereotactic radiosurgery alone for metastatic intracranial tumors.
The average survival of this patient sample was 14.3 months. A higher prevalence of single metastasis in the respective cohort was the only specific preoperative or patient factor that was associated with higher overall survival.
A mean of 83% of patients achieved a crude arrest of cancer growth local to the site of origin. An analysis conducted by half of the studies in the review found a median rate of 1-year local control of 81% (mean of 85%).
Crude local control significantly correlated separately and together with smaller tumor volumes treated with radiosurgery and the rate of gross total resection.
Distant intracranial recurrence (failure) occurred in a median of 49% of the patients, while 29% required salvage WBRT, which was the most common method of salvage in the studies that were reviewed.
Neither crude local control rate, nor median overall survival, were affected by the use of a radiosurgical margin - regardless of size. The authors noted that the advantage of adding a radiosurgical margin between 1 mm and 3 mm around the resection cavity is controversial in terms of increased local control and overall survival.
"Large margins also risk significant radiation-related parenchymal changes, which although sometimes asymptomatic may cause cognitive disturbance," the authors write. Complications arising from radiation treatments, such as edema, are likely underreported, the researchers add.
"Direct comparisons evaluating patient satisfaction and quality of life between WBRT and SRS are needed to adequately compare the serious complications of each treatment approach," Gans and team suggest.
Both a smaller target tumor volume, which allows for greater efficacy for radiosurgery, and gross total resection, which increases local control, "represent the possible optimal situation for adjuvant radiosurgery," conclude the authors.
By Peter Sergo, medwireNews Reporter