Survival among patients with central nervous system metastases who underwent cranial radiation varied considerably based on breast cancer subtype, according to study results presented at the Breast Cancer Symposium.
Many prognostic factors used for patients with breast cancer and brain metastases were identified before stereotactic radiosurgery became common, according to background information provided by researchers.
In the current study, researchers retrospectively evaluated outcomes and characteristics of patients with breast cancer and CNS metastases who underwent cranial radiation at Memorial Sloan-Kettering Cancer Center.
The study included 173 patients who received stereotactic radiosurgery or whole-brain radiation therapy (WBRT) between January 2009 and December 2011.
Researchers identified HER-2 status for 171 patients. The breakdown was: HR-positive and HER-2–negative (n=77); HR-positive, HER-2–positive (n=28); HR-negative and HER-2–positive (n=17); and HR-negative and HER-2–negative (n=49).
Among patients with known HER-2 status, 50 underwent stereotactic radiosurgery and 121 underwent WBRT. Four patients in the WBRT group underwent prior stereotactic radiosurgery.
Use of stereotactic radiosurgery varied by disease subtype, ranging from 21% of patients with HR-positive, HER-2–negative disease to 59% for patients with HR-negative, HER-2–positive disease.
Researchers reported 110 deaths. Median follow-up for surviving patients was 19 months (range, 6-67).
Overall, Kaplan-Meier and log-rank analyses showed the median time from brain metastases to death was 17.5 months (95% CI, 14-20 months).
The time from metastases to death varied by subtype: 14.5 months for HR-positive, HER-2–negative; 63 months for HR-positive, HER-2–positive; 41 months for HR-negative, HER-2–positive; and 14 months for HR-negative, HER-2–negative.
“Although HER-2–positive and triple negative breast cancer subtypes are associated with a higher risk of brain metastases, we noted a higher prevalence of HR-positive, HER-2–negative disease in breast cancer patients with CNS metastasis, a group currently understudied,” the researchers wrote. “The prognostic information from brain metastases to death differs according to subtype and may be important for future planning of clinical trials. Further evaluation of factors related to these outcomes is ongoing.”
Disclosure: The researchers report research funding from Merck.
For more information:
Morikawa A. Abstract #144. Presented at: Breast Cancer Symposium; Sept. 7-9, 2013; San Francisco.