Adding carboplatin and/or bevacizumab to the standard treatment regimen significantly improved pathologic complete response rates in patients with triple-negative breast cancer, according to a new phase 2 study.
Because of its rapid growth rate, many women with triple-negative breast cancer receive chemotherapy to try to shrink it before undergoing surgery. With the standard treatment, the cancer is eliminated from the breast and lymph nodes in the armpit before surgery in about one third of women. This is referred to as a pathologic complete response (pCR). In patients who achieve pCR, the cancer is much less likely to come back, spread to other parts of the body, and cause the patient’s death than if the cancer survives the chemotherapy.
William M. Sikov, MD, of Women & Infants Hospital of Rhode Island, and his collaborators studied the addition of carboplatin and/or bevacizumab to the standard treatment regimen to see if they could increase response rates. More than 440 women from cancer centers across the country enrolled in this randomized clinical trial. The results were published in the Journal of Clinical Oncology (2014; doi:10.1200/JCO.2014.57.0572).
“Adding either of these medications significantly increased the percentage of women who achieved a pCR with the preoperative treatment. We hope that this means fewer women will relapse and die of their cancer, though the study is not large enough to prove this conclusively. Of the two agents we studied, we are more encouraged by the results from the addition of carboplatin, since it was associated with fewer and less concerning additional side effects than bevacizumab,” Sikov explained.
“More studies are planned to confirm the role of carboplatin in women with triple-negative breast cancer, and also to see if we can better identify which of these patients are most likely to benefit from its use. Until we have those results, medical oncologists who treat women with triple-negative breast cancer will have to decide whether the potential benefits of adding carboplatin outweigh its risks for each individual patient.”
Triple-negative breast cancer accounts for 15% to 20% of invasive breast cancers diagnosed in the United States each year, and is more common in younger women, African Americans, Hispanics, and BRCA1-mutation carriers. With no identified characteristic molecular abnormalities that can be targeted with medication, the current standard of treatment is chemotherapy.
“Overall prognosis for women with this type of breast cancer remains inferior to that of other breast cancer subtypes, with higher risk of early relapse,” Sikov said.