The gist: Women with basal-like triple-negative breast cancer (TNBC) might benefit from adding either the drug bevacizumab (Avastin) or the drug carboplatin to their chemotherapy treatment before tumor-removal surgery (neoadjuvant chemotherapy). For non-basal-like TNBC patients, carboplatin shows similar benefit, but bevacizumab may actually worsen their treatment response.
“A study of women with triple-negative breast cancer (TNBC) has shown that women with the basal-like subtype of breast cancer had higher rates of pathologic complete response (pCR) with the addition of bevacizumab (Avastin) to neoadjuvant chemotherapy than did women with non–basal-like breast cancer. No difference in response was seen between the two subtypes for the addition of carboplatin.
“These results were part of a subtype analysis of the CALGB/Alliance 40603 study and were presented at the 2014 San Antonio Breast Cancer Symposium, held December 9–13 in San Antonio, Texas, by William M. Sikov, MD, associate director of clinical research for the program in women’s oncology at Women and Infants Hospital and associate professor of medicine at Alpert Medical School of Brown University in Providence, Rhode Island.
“Earlier this year, results of the initial study of 443 women published in the Journal of Clinical Oncology showed that the addition of carboplatin or bevacizumab to neoadjuvant chemotherapy in women with stage II to III TNBC increased rates of pCR. In the subtype analysis, Sikov and colleagues sought to identify subgroups of patients who were more or less likely to benefit from the addition of these therapies.
“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.)”
Editor’s note: Drugs known as targeted therapies can be used to treat some forms of cancer, based on specific substances found in cancer cells. Scientists have identified a protein called STAT3, which is found in basal-like breast cancer. Drugs that target STAT3 are being tested in volunteer patients in clinical trials.
“Two Northwestern University scientists have identified a biomarker strongly associated with basal-like breast cancer, a highly aggressive carcinoma that is resistant to many types of chemotherapy. The biomarker, a protein called STAT3, provides a smart target for new therapeutics designed to treat this often deadly cancer.
“Using breast cancer patient data taken from The Cancer Genome Atlas, molecular biologists Curt M. Horvath and Robert W. Tell used powerful computational and bioinformatics techniques to detect patterns of gene expression in two cancer subtypes. They found that a small number of genes are activated by STAT3 protein signaling in basal-like breast cancers but not in luminal breast cancers.
“Basal-like cancer is a category that includes a number of different breast cancers, including the highly aggressive form called triple negative cancer.”