The results of a recent study indicate that women with HER2-positive metastatic breast cancer should receive trastuzumab and, potentially, chemotherapy, even if the cancer has spread to the brain.
“It is surprising that chemotherapy/trastuzumab adds to these women’s survival,” noted lead researcher Adam Brufsky, MD, PhD, in a statement describing his team’s findings. “We thought that the brain metastases would be dominant in this regard no matter what therapy.”
Brufsky, a professor of medicine and associate director of clinical investigation at the University of Pittsburgh (Pennsylvania) Cancer Institute, and colleagues explained in their report for Clinical Cancer Research (2011;17:4834-4843) that 10% to 16% of women with advanced breast cancer develop central nervous system (CNS) metastases. Using data from registHER—a prospective, observational study of 1,023 women with newly diagnosed HER2-positive metastatic breast cancer—the investigators compared baseline characteristics of patients with and without CNS metastases: incidence, time to development, treatment, and survival after assessment of CNS metastases.
Of the 1,012 women with confirmed HER2-positive tumors, 377 (37.3%) had CNS metastases. These women were younger and more likely to have hormone receptor-negative disease and higher disease burden than those with no CNS metastases. Among the 302 patients without CNS disease at initial diagnosis of metastatic breast cancer, median time to CNS progression was 13.3 months.
Brufsky and associates found that treatment with trastuzumab, chemotherapy, or surgery after CNS diagnosis was each associated with a statistically significant improvement in median overall survival, as indicated by unadjusted analysis:
- trastuzumab vs. no trastuzumab: 17.5 vs. 3.8 months
- chemotherapy vs. no chemotherapy: 16.4 vs. 3.7 months
- surgery vs. no surgery: 20.3 vs. 11.3 months.
Further analyses confirmed the independent significant effects of trastuzumab and chemotherapy, but the effects of surgery and radiotherapy (which seemed to prolong median overall survival as well: 13.9 vs. 8.4 months with and without radiotherapy, respectively) did not reach statistical significance.
“Women with HER2-positive breast cancer have a reasonable chance of living a long time with their disease, and they should be given aggressive therapy where appropriate,” commented Brufsky.