In a nationwide study of women with triple-negative breast cancer, adding the chemotherapy drug carboplatin or the angiogenesis inhibitor Avastin (bevacizumab) to standard chemotherapy drugs brought a sharp increase in the number of patients whose tumors shrank away completely. This was reported at the 2013 San Antonio Breast Cancer Symposium, December 10-14, 2013.
The results are especially promising in the case of carboplatin, study leaders said, as bevacizumab has shown little effectiveness as a long-term preventer of cancer recurrence.
“Our findings suggest that carboplatin could be used either in addition to or instead of some of the drugs in the standard chemotherapy regimen for women with triple-negative breast cancer,” said the study’s senior author, Eric Winer, MD, chief of the division of Women’s Cancers in the Susan F. Smith Center for Women’s Cancers at Dana-Farber Cancer Institute in Boston, Massachusetts.
Triple-negative breast cancer, named for the lack of three growth-spurring receptors on its cells’ surface, accounts for 15% to 25% of all breast cancer cases. Although it often goes into remission in response to chemotherapy, it can be more aggressive and more likely to recur than other breast cancers. Because of the dearth of three common receptors on the cell surface, triple-negative cancers usually are not vulnerable to drugs that block these receptors in other types of breast cancer.
The current study involved 450 women with stage 2 or stage 3 triple-negative breast cancer. It was sponsored by the Cancer and Leukemia Group B, which is part of the Alliance for Clinical Trials in Oncology, a national clinical research network supported by the National Cancer Institute. As a presurgery treatment, the women were randomly assigned to receive either standard chemotherapy (a combination of paclitaxel, adriamycin, and cyclophosphamide), standard chemotherapy plus carboplatin, standard chemotherapy plus bevacizumab (a drug that blocks cancers from generating blood vessels), or standard chemotherapy plus both carboplatin and bevacizumab.
Among patients who received standard chemotherapy alone, 34% had their tumors disappear. That compares with 48% of patients in the chemotherapy plus carboplatin group, 51% of those in the chemotherapy plus bevacizumab group, and 61% of those in the chemotherapy plus carboplatin and bevacizumab group.
Promising as the results are, “more research is needed to determine which women with triple-negative breast cancer particularly benefit from add[ing] carboplatin and which do not,” said Winer. “As we learn more about triple-negative breast cancer, we’ll be better able to determine which set of drugs is most effective for individual patients.