Surgical tumor removal followed by stereotactic radiosurgery significantly lowers rates of tumor recurrence compared with tumor removal alone.
Cancer metastases to the brain are a major healthcare burden. For single metastases, surgical removal of the tumor followed by whole brain radiotherapy (WBRT) is the standard of care and has been shown to improve survival compared with WBRT alone. However, although WBRT decreases the likelihood of tumor recurrence, it may also decrease cognitive function.
A study by Anita Mahajan and colleagues published in the Lancet Oncology aimed to determine if stereotactic radiosurgery (SRS) improved the time to local tumor recurrence compared with surgical resection alone. After tumor resection, stereotactic radiosurgery can be used to deliver a high dose of targeted radiation to the margins of the surgical cavity. Thus, stereotactic radiosurgery should decrease tumor recurrence with fewer negative side effects compared with WBRT.
The phase 3 clinical trial included 128 patients who had undergone complete resection of one to three brain metastases. Of these, 65 patients were randomly assigned to the observation group, while 63 were assigned to the SRS group.
All patients in the SRS group received a single treatment session within 30 days of surgery using the ElektaPerfexion Gamma Knife unit (Elekta, Stockholm, Sweden). Stereotactic radiosurgery target volume for each patient was calculated using volumetric MRI scans.
Median follow-up time was 11.1 months (IQR 4.8-20.4 months). In the observation group, 31 (48%) of 65 patients had tumor recurrence in the treated area. In the stereotactic radiosurgery group, 15 (24%) of 63 patients had a recurrence at the treatment site. Additionally, 12-month freedom from local tumor recurrence was 72% in the stereotactic radiosurgery treatment group versus 43% in the observation group (hazard ratio 0.46; p = 0.015).No adverse events or treatment-related deaths were reported during the study.
In conclusion, use of stereotactic radiosurgery after resection of brain metastases significantly reduces local tumor recurrence compared with observation alone. Furthermore, stereotactic radiosurgery may be an effective alternative whole-brain radiation.
Written by Cindi A. Hoover, Ph.D.
Reference: Mahajan A, Ahmed S, McAleer MF, Weinberg JS, Li J, Brown P, Settle S, Prabhu SS, Lang FF, Levine N, McGovern S, Sulman E, McCutcheon IE, Azeem S, Cahill D, Tatsui C, Heimberger AB, Ferguson S, Ghia A, Demonte F, Raza S, Guha-Thakurta N, Yang J, Sawaya R, Hess KR, Rao G. Post-operative stereotactic radiosurgery versus observation for completely resected brain metastases: a single-centre, randomized, controlled, phase 3 trial. 2017. Lancet Oncol.http://dx.doi.org/10.1016/S1470-2045(17)30414-X