Radiation therapy for brain metastases from breast cancer

Breast cancer is one of the most common malignancies that metastasize to the brain. Radiation therapy plays a central role in the management of brain metastases.

The medical records of 36 patients with brain metastases from breast cancer who underwent whole-brain radiation therapy (WBRT) at Kyoto University Hospital between 1993 and 2001 were reviewed. The treatment outcomes were analyzed retrospectively.

The median age at the time of diagnosis of brain metastases was 52 years. Only 4 patients (11%) had a single metastasis, while the others had multiple metastases. Uncontrolled extracranial metastases were present in 26 patients at the time of diagnosis of brain metastases. All patients received WBRT at a median dose of 31 Gy. Eight patients received conventional external-beam boost irradiation, and 2 received boost stereotactic radiosurgery (SRS). The overall median survival time was 7.9 months. Uncontrolled extracranial metastases except for bone metastases and old age were significantly associated with a poor survival rate. Twenty-six patients (82%) showed initial response, but 15 developed CNS failure, including 9 patients whose tumor recurred at the original site, 4 patients who developed tumors elsewhere in the brain and 3 patients who exhibited meningeal spread. The median duration of intracranial failure was 5.0 months. Whole-brain dose, and total tumor dose did not affect intracranial control.

Radiation therapy yielded a high initial response, but the duration of effect was limited with external beam irradiation alone. New treatment strategies such as adding SRS need to be studied further.