Radiosurgery alone can achieve local control of brain metastases

By Andrew Czyzewski, medwireNews Reporter

medwireNews: Radiosurgery to the surgical cavity without whole-brain radiotherapy (WBRT) achieves good rates of local control in patients with brain cancer metastases, a study has shown.

Nevertheless, around a third of the patients did require salvage WBRT for new metastases, indicating that close clinical and imaging follow up is required for the radiosurgery approach.

"For select patients with a good chance of longer survival, limited brain disease, and a lower risk of developing new metastasis, the local therapy approach of surgical excision plus radiosurgery is a good treatment option," Samuel Ryu (Henry Ford Hospital, Detroit, Michigan, USA) and colleagues comment.

Surgical resection followed by WBRT has been used as the main treatment option for limited intracranial metastasis, particularly for single lesions. This is supported by randomized trials and by the recommendations of several treatment guideline committees.

However, WBRT has been associated with neurocognitive decline and memory dysfunction.

"We questioned whether local treatment with radiosurgery to the surgical bed could be used instead of WBRT and how and when salvage treatments would need to be delivered with this treatment paradigm," Ryu et al comment in Neurosurgery.

To address this they identified a total of 85 consecutive patients treated at their institution between August 2000 and March 2011 with surgical resection followed by stereotactic radiosurgery (SRS) to the surgical cavity.

Lung cancer accounted for the majority of cases (59%), and most patients (62%) had a single brain metastasis at the time of treatment.

The median target volume for radiosurgery was 13.95 cm³ and the median marginal radiosurgery dose was 16 Gy.

Ryu et al report that after a median follow up of 11.2 months only 16 local failures (reappearance in exactly the same site as the first site of metastasis) were observed and the overall local control rate was 81.2%. The 6-month, 1-year, and 2-year rates of local control were 88.7%, 81.4%, and 75.7%, respectively.

Meanwhile, 47 (55%) patients developed new intracranial metastases after initial treatment with surgery and SRS. For this group, the median time to develop new metastases was 5.6 months. For the entire population, the rates of developing new metastases at 6 months, 1 year, and 2 years were 32.1%, 58.1%, and 62.9%, respectively.

From initial treatment until death or last follow up, only 30 (35%) patients received WBRT as salvage treatment.

"Considerations for the potential complication of neurocognitive decline after WBRT must be weighed against the risk of developing additional intracranial metastasis," Ryu et al conclude.

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