Stereotactic radiosurgery (SRS) provides better early local control of brain metastases than complete surgical resection, but this advantage fades with time, according to investigators.
By 6 months, lower risks associated with SRS shifted in favor of those who had surgical resection, reported lead author Thomas Churilla, MD, of Fox Chase Cancer Center in Philadelphia and his colleagues.
“Outside recognized indications for surgery such as establishing diagnosis or relieving mass effect, little evidence is available to guide the therapeutic choice of SRS vs. surgical resection in the treatment of patients with limited brain metastases,” the investigators wrote in JAMA Oncology.
The investigators performed an exploratory analysis of data from the European Organization for the Research and Treatment of Cancer (EORTC) 22952-26001 phase 3 trial, which was designed to evaluate whole-brain radiotherapy for patients with one to three brain metastases who had undergone SRS or complete surgical resection. The present analysis involved 268 patients, of whom 154 had SRS and 114 had complete surgical resection.
Primary tumors included lung, breast, colorectum, kidney, and melanoma. Initial analysis showed that patients undergoing surgical resection, compared with those who had SRS, typically had larger brain metastases (median, 28 mm vs. 20 mm) and more often had 1 brain metastasis (98.2% vs. 74.0%). Mass locality also differed between groups; compared with patients receiving SRS, surgical patients more often had metastases in the posterior fossa (26.3% vs. 7.8%) and less often in the parietal lobe (18.4% vs. 39.6%).
After median follow-up of 39.9 months, risks of local recurrence were similar between surgical and SRS groups (hazard ratio, 1.15). Stratifying by interval, however, showed that surgical patients were at much higher risk of local recurrence in the first 3 months following treatment (HR for 0-3 months, 5.94). Of note, this risk faded with time (HR for 3-6 months, 1.37; HR for 6-9 months, 0.75; HR for 9 months or longer, 0.36). From the 6-9 months interval onward, surgical patients had lower risk of recurrence, compared with SRS patients, and the risk even decreased after the 6-9 month interval.
“Prospective controlled trials are warranted to direct the optimal local approach for patients with brain metastases and to define whether any population may benefit from escalation in local therapy,” the investigators concluded.
The study was funded by the National Cancer Institute, National Institutes of Health, and Fonds Cancer in Belgium. One author reported receiving financial compensation from Pfizer via her institution.
SOURCE: Churilla T et al. JAMA Onc. 2018. doi: 10.1001/jamaoncol.2018.4610.