A Phase 2 Trial of Stereotactic Radiosurgery Boost After Surgical Resection for Brain Metastases

Abstract

Purpose/Objective To evaluate local control following surgical resection and postoperative stereotactic radiosurgery (SRS) for brain metastases. Methods and Materials Forty-nine patients (50 lesions) were enrolled and available for analysis. Eligibility criteria included histologically confirmed malignancy with 1 or 2 intraparenchymal brain metastases, age ≥18, and KPS ≥70. Cox proportional hazard regression model was used to test for significant association between clinical factors and overall survival (OS). Competing risks regression models, as well as cumulative incidence functions, were fit using the method of Fine and Gray in order to assess the association between clinical factors and both local failure (LF, recurrence within surgical cavity or SRS target), and regional failure (RF, intracranial metastasis outside of treated volume). Results The median follow-up was 12.0 months (mos, range: 1.0–94.1 mos). Following surgical resection, 39 patients with 40 lesions were treated a median of 31 days (range: 7–56 days) later with SRS to the surgical bed to a median dose of 1800 cGy (range: 1500–2200 cGy). Of the 50 lesions, 15 (30%) demonstrated LF after surgery. The cumulative LF and RF rates were 22% and 44% at 12 mos. Patients who went on to receive SRS had significantly lower incidence of LF (p=0.008). Other factors associated with improved local control includes NSCLC histology (p=0.048), tumor diameter <3 cm (p=0.010), and deep parenchymal tumors (p=0.036). Large tumors (≥3 cm) with superficial dural/pial involvement showed the highest risk for LF (53.3% at 12 mos). Large, superficial lesions treated with SRS had 54.5% LF. Infratentorial lesions were at higher risk of developing RF compared to supratentorial lesions (p <0.001). Conclusions Postoperative SRS is associated with high local control, especially for deep brain metastases <3 cm. Tumors ≥3 cm with superficial dural/pial involvement demonstrate the highest risk in LF.

Radiosurgery for Brain Metastases: Changing Practice Patterns and Disparities in the United States

“…8,10,11 The timing of publication of these studies coincides with an observed increase in the uptake of SRS. During our study period, multiple institutional SRS series were published, demonstrating promising efficacy for up to, and beyond, 10 intracranial lesions, [20][21][22] in elderly patients, 23 and in the postoperative setting, 24 indicating an increased practitioner comfort level with brain SRS for a number of clinical situations.…”

Diagnosis and treatment of brain metastases from solid tumors: guidelines from the European Association of Neuro-Oncology (EANO)

“…Several retrospective [42][43][44] and one prospective phase II trial 45 reported local control rates at 1 year around 80% (70%-90%) and a median survival of 10-17 months (class IIIa): this suggests that postoperative SRS is as effective as WBRT in achieving local control. An alternative approach is the use of SFRT, presumed to be associated with lower risk of radionecrosis in larger lesions.…”

Treatment of Brain Metastases

“…Both single- and multi-dose SRS have been looked at as potential methods for delivering focal RT to the resection cavity. Prospective and retrospective evaluations of single- and multi-dose SRS to the resection cavity after brain metastasis surgery revealed excellent local control rates [24,25,26,27]. …”