Treatment of Solitary Brain Metastasis: Resection Followed by Whole Brain Radiation Therapy (WBRT) and a Radiation Boost to the Metastatic Site

Background: Whole brain radiation therapy (WBRT) is reported to improve local control after resection of brain metastases. Improvement of survival was only observed in patients with controlled extracranial disease. The optimum radiation schedule has yet to be defined. The authors' experience with a postoperative approach including WBRT and a radiation boost to the metastatic site is presented. Patients and Methods: Criteria for inclusion into this retrospective analysis were solitary brain metastasis, Karnofsky performance status ≥ 70%, and controlled extracranial disease. Two therapies were compared for local control and survival: surgery followed by 40 Gy WBRT (group A) versus surgery followed by 40 Gy WBRT and a 10 Gy boost (group B). Statistical analysis was performed using the Kaplan-Meier method and log-rank test. Results: 33 patients were included (17 group A, 16 group B). The results suggested better local control (p = 0.0087) and survival (p = 0.0023) for group B. 17/17 patients (100%) of group A and 13/16 patients (81%) of group B showed progression of brain metastasis, 8/17 and 3/16 patients in the area of metastatic surgery. Median time to progression was 7 (1-22) months in group A and 12 (3-42) months in group B. The number of cancer-related deaths amounted to 17/17 (100%) in group A after a median interval of 9 (3-26) months, and to 9/16 (56%) in group B after 14 (4-46) months. Conclusion: After resection of solitary brain metastasis, a radiation boost in addition to WBRT seems to improve tocar local control and survival when compared to postoperative WBRT alone. The results should be confirmed in a larger prospective trial.