Do patients with very few brain metastases from breast cancer benefit from whole-brain radiotherapy in addition to radiosurgery?

BACKGROUND An important issue in palliative radiation oncology is the whether whole-brain radiotherapy should be added to radiosurgery when treating a limited number of brain metastases. To optimize personalized treatment of cancer patients with brain metastases, the value of whole-brain radiotherapy should be described separately for each tumor entity. This study investigated the role of whole-brain radiotherapy added to radiosurgery in breast cancer patients. METHODS Fifty-eight patients with 1-3 brain metastases from breast cancer were included in this retrospective study. Of these patients, 30 were treated with radiosurgery alone and 28 with radiosurgery plus whole-brain radiotherapy. Both groups were compared for local control of the irradiated metastases, freedom from new brain metastases and survival. Furthermore, eight additional factors were analyzed including dose of radiosurgery, age at radiotherapy, Eastern Cooperative Oncology Group (ECOG) performance score, number of brain metastases, maximum diameter of all brain metastases, site of brain metastases, extra-cranial metastases and the time from breast cancer diagnosis to radiotherapy. RESULTS The treatment regimen had no significant impact on local control in the univariate analysis (p=0.59). Age ≤59 years showed a trend towards improved local control on univariate (p=0.066) and multivariate analysis (p=0.07). On univariate analysis, radiosurgery plus whole-brain radiotherapy (p=0.040) and ECOG 0-1 (p=0.012) showed positive associations with freedom from new brain metastases. Both treatment regimen (p=0.039) and performance status (p=0.028) maintained significance on multivariate analysis. ECOG 0-1 was positively correlated with survival on univariate analysis (p<0.001); age ≤59 years showed a strong trend (p=0.054). On multivariate analysis, performance status (p<0.001) and age (p=0.041) were significant. CONCLUSIONS In breast cancer patients with few brain metastases, radiosurgery plus whole-brain radiotherapy resulted in significantly better freedom from new brain metastases than radiosurgery alone. However, this advantage did not lead to significantly better survival.