Combination of carboplatin and chemotherapy improves outcomes for triple-negative breast cancer patients

In a clinical trial involving women with triple-negative breast cancer, patients who received the drugs carboplatin and/or bevacizumab in combination with standard chemotherapy prior to surgery were more likely to have their tumors disappear entirely from the breast, according to data presented by investigators during the 2014 San Antonio Breast Cancer Symposium.

Although bevacizumab doesn't reduce long-term rates of cancer recurrence, the results raise hopes that carboplatin can be an important part of the fight against triple-negative cancer, say the leaders of the study, which was organized by the Alliance for Clinical Trials in Oncology with extensive involvement of physician/scientists at Dana-Farber Cancer Institute.

The investigators analyzed data from 360 patients with triple-negative breast cancer, the vast majority of whom had a form of the disease known as basal-like tumors. Triple-negative cancer, named for its cells' lack of three key receptors, accounts for about 15-20 percent of all breast cancers and tends to be aggressive, but can often be treated successfully if caught early. Basal-like tumors are made up of cells that resemble the basal cells lining the milk ducts.

In the trial, patients with triple-negative breast cancer were treated with "neoadjuvant" chemotherapy — which helps shrink tumors so they can be surgically removed — either alone or in combination with bevacizumab or carboplatin or both. (Bevacizumab prevents tumors from developing networks of blood vessels; carboplatin is a platinum-based chemotherapy agent.)

The researchers found that 61 percent of patients with basal-like tumors who received a combination of carboplatin and chemotherapy experienced a pathologic complete response — no microscopic evidence of cancer in the breast following surgery to remove tumor tissue — compared to 47 percent of those who received chemotherapy alone. Roughly the same improvement was seen in patients with other types of triple-negative breast cancer.

"In general, patients with triple-negative breast cancer who have a pathological complete response (pCR) with neoadjuvant chemotherapy are much less likely to experience a recurrence," says the study's senior author, Eric Winer, MD, director of Breast Oncology at the Susan F. Smith Center for Women's Cancers at Dana-Farber. "While we are optimistic about the role of carboplatin in triple negative breast cancer, we still do not know if it will lead to a high cure rate. Ongoing studies are addressing this issue and attempting to determine how and in whom to use carboplatin."

Funding for the study was provided by the National Cancer Institute, Roche-Genentech, and the Breast Cancer Research Foundation.

The lead author of the study is William Sikov, MD, of Brown University. Co-authors are William Barry, PhD, Sara Tolaney, MD, and Mehra Golshan, MD, of Dana-Farber; Katherine Hoadley, PhD, and Charles Perou, PhD, of University of North Carolina Lineberger Comprehensive Cancer Center; Brandelyn Pitcher, MS, of Alliance Statistical Center, Durham, N.C.; Baljit Singh, MD, of New York University Medical Center; Charles Kuzma, MD, of Southeast Cancer Control Consortium; Timothy Pluard, MD, of Washington University-St Louis Medical Center; George Somlo, MD, of City of Hope Comprehensive Cancer Center; Elisa Port, MD, of Mount Sinai Medical Center, New York, N.Y.; Donald Berry, PhD, and Lisa Carey, MD, of MD Anderson Cancer Center; Olwen Hahn, MD, of University of Chicago Medical Center; and Clifford Hudis, MD, of Memorial Sloan Kettering Cancer Center.