Adding Carboplatin to Chemotherapy May Improve Treatment Response in Triple-Negative Breast Cancer
Researchers suggest more studies be done on carboplatin to find out if it could have long-term benefits and to see what types of people with triple-negative breast cancer it helps most.
Background and Goals
Between 15 and 20 percent of invasive breast cancers are triple-negative, meaning tumors do not express the estrogen receptor, progesterone receptor, or the HER2 protein. Unlike other types of breast cancer, there is no targeted therapy, medicines that attack specific targets on cancer cells, such as the estrogen receptor or HER2, for triple-negative breast cancer (TNBC). Instead, doctors largely rely on systemic therapy, such as chemotherapy, which attacks both healthy and unhealthy cells throughout the whole body, to treat this subtype of cancer.
After pre-surgery treatment with anthracycline- and taxane-based chemotherapy, about one-third of people who have stage II to III TNBC experience pathologic complete response, pCR, in which invasive cancer can no longer be found in the breast.
Researchers with the CALGB40603 (Alliance) trial looked at carboplatin (Paraplatin), part of a group of chemotherapy medicines called platinums; and bevacizumab (Avastin), a medicine that treats cancer by slowing the growth of new blood vessels. They studied whether adding one or both of the medicines to standard chemotherapy would make it more likely for people with TNBC to achieve pCR.
The study’s 443 participants, who had untreated, stage II to III TNBC, were divided randomly into one of four groups. Each group received anthracycline- and taxane-based chemotherapy and
- Group 1: no other treatment
- Group 2: carboplatin
- Group 3: bevacizumab
- Group 4: carboplatin and bevacizumab
pCR was seen in
- 42 percent of the chemotherapy-only group
- 50 percent of the chemotherapy and bevacizumab group
- 53 percent of the chemotherapy and carboplatin group
- 67 percent of those who received all three
Side effects, such as low white blood cell count and low blood platelet count, were seen more often in participants taking carboplatin. High blood pressure, infection, blood clots in the brain or heart, bleeding, and complications after surgery were seen more often in participants taking bevacizumab. These side effects made it more likely that people who took these medicines would skip doses, need their doses reduced or stop taking the chemotherapy.
Though the study medicines did increase pCR, the researchers don’t yet recommend them for routine use by doctors, because of side effects and because there is no evidence yet that the medicines provide long-term benefits, such as prevention of a breast cancer recurrence.
What This Means for You
If you have triple-negative breast cancer, you may know other people who have a different kind of breast cancer that allows them to receive targeted therapies. You may feel frustrated that you don’t have that option yet.
It may comfort you to know that there is a large amount of research happening on this topic. Researchers want to learn more about TNBC so that they can help people like you get better and live a life beyond the disease.
Because other studies have not had clear results about bevacizumab’s use in TNBC, the researchers say there is little interest in continuing to study it in the early-stage setting. But they suggest more studies of carboplatin take place to learn if certain types of people with TNBC benefit more from it and to see if it has long-term benefits.
To learn more about clinical trials involving triple-negative breast cancer, talk to your doctor and visit ClinicalTrials.gov.
In the past, bevacizumab was FDA-approved for treating metastatic breast cancer, but that approval was revoked in 2011 because of doubts about the medicine’s safety and effectiveness. It is not easily available for metastatic or early-stage disease in the U.S., and insurance might not cover it.
Sikov, William M.; Berry, Donald A.; Perou, Charles M. et al. Impact of the Addition of Carboplatin and/or Bevacizumab to Neoadjuvant Once-per-Week Paclitaxel Followed by Dose-Dense Doxorubicin and Cyclophosphamide on Pathologic Complete Response Rates in Stage II to III Triple-Negative Breast Cancer: CALGB 40603 (Alliance). Journal of Clinical Oncology. Published online August 4, 2014; doi: 10.1200/JCO.2014.57.0572.