Background: The optimal treatment for patients with a single brain metastasis is controversial. This study investigated the value of a radiation boost given in addition to neurosurgerical resection and whole-brain irradiation (WBI).
Patients and methods: In this retrospective study, outcome data of 105 patients with a single brain metastasis receiving metastatic surgery plus WBI (S + WBI) were compared to 90 patients receiving the same treatment plus a boost to the metastatic site (S + WBI + B). The outcomes that were compared included local control of the resected metastasis (LC) and overall survival (OS). In addition to the treatment regimen, eight potential prognostic factors were evaluated including age, gender, performance status, extent of metastatic resection, primary tumor type, extracerebral metastases, recursive partitioning analysis (RPA) class, and interval from first diagnosis of cancer to metastatic surgery.
Results: The LC rates at 1 year, 2 years, and 3 years were 38%, 20%, and 9%, respectively, after S + WBI, and 67%, 51%, and 33%, respectively, after S + WBI + B (p = 0.002). The OS rates at 1 year, 2 years, and 3 years were 52%, 25%, and 19%, respectively, after S + WBI, and 60%, 40%, and 26%, respectively, after S + WBI + B (p = 0.11). On multivariate analyses, improved LC was significantly associated with OP + WBI + B (p = 0.006) and total resection of the metastasis (p = 0.014). Improved OS was significantly associated with age ≤ 60 years (p = 0.028), Karnofsky Performance Score > 70 (p = 0.015), breast cancer (p = 0.041), RPA class 1 (p = 0.012), and almost with the absence of extracerebral metastases (p = 0.05).
Conclusion: A boost in addition to WBI significantly improved LC but not OS following resection of a single brain metastasis.