In women with HER2-positive metastatic breast cancer, use of trastuzumab along with chemotherapy improved survival rate.
Based on these study results, lead researcher Adam Brufsky, M.D., Ph.D., said, "We clearly now know that these women should get trastuzumab and potentially chemotherapy, even if cancer spreads to the brain."
"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," added Brufsky, professor of medicine and associate director of clinical investigation at the University of Pittsburgh Cancer Institute.
Ten to 16 percent of women with advanced breast cancer develop central nervous system metastases, the researchers wrote in their study, published in Clinical Cancer Research
, a journal of the American Association for Cancer Research.
Brufsky and colleagues used data from the registHER study to evaluate the incidence, potential risk factors and outcomes for patients with HER2-positive breast cancer. They evaluated how patients with HER2-positive breast cancer develop brain metastases, and followed them to examine what happens thereafter.
Of the 1,023 women newly diagnosed with HER2-positive metastatic breast cancer, 377 had central nervous system metastases.
Patients with central nervous system metastases were younger, and more likely to have hormone receptor negative disease and higher disease burden compared with those whose cancer did not spread to the brain. In addition, for those patients without central nervous system metastases at initial diagnosis, cancer progressed to the brain about 13 months after diagnosis.
For those diagnosed with central nervous system metastases, treatment with trastuzumab, chemotherapy or surgery was each associated with a significant improvement in overall survival: trastuzumab 17.5 months vs. no trastuzumab 3.8 months; chemotherapy 16.4 months vs. no chemotherapy 3.7 months; and surgery 20.3 months vs. no surgery 11.3 months.
"It is surprising that chemotherapy/trastuzumab adds to these women's survival," Brufsky said. "We thought that the brain metastases would be dominant in this regard no matter what therapy."