Carboplatin Helpful in Treating Triple-Negative Breast Cancer Before Surgery

Breast Cancer News
September 18, 2014
By: 
Erin Rowley, Writer and Content Coordinator
Reviewed By: 
Harry D. Bear, MD, PhD

Researchers with the phase II GeparSixto trial found that women with triple-negative breast cancer were significantly more likely to achieve pathological complete response, or pCR, when carboplatin was added to their course of other anti-cancer medicines. For this study, pCR was defined as the absence of cancer after treatment given before surgery.

Background and Goals

Anthracyclines are a family of chemotherapy antibiotics that damage the DNA in cancer cells. Taxane chemotherapy medicines treat cancer by blocking cell growth. Targeted therapies can hone in on the cancer cells, rather than treating the whole body. Sometimes, doctors will give all three of these medicines at once.

Researchers with the GeparSixto trial wondered what effect carboplatin (Paraplatin), part of a group of chemotherapy medicines called platinums, would have on pCR when added to this combination treatment. They looked specifically at women with HER2-positive breast cancer, which grows and spreads faster because it expresses high levels of a protein called human epidermal growth factor receptor-2, HER2; and triple-negative breast cancer, or TNBC. Little is known about what causes triple-negative cancer cells to grow.

Based on past studies, they expected to see pCR in

  • 40 percent of women who did not receive carboplatin
  • 49 percent of women who did receive carboplatin

Design

The study involved 588 women with untreated, early-stage, triple-negative or HER2-positive breast cancer. The 293 women in the control group received an anthracycline, a taxane and a targeted therapy. The 295 women in the treatment group received those medicines along with the study medicine, carboplatin. Depending on whether they had HER2-positive or triple-negative disease, the women received different targeted therapies:

  • Those with HER2-positive breast cancer were given a combination of trastuzumab (Herceptin) and lapatinib (Tykerb)
  • Those with TNBC were given bevacizumab (Avastin)

Results

The researchers found pCR was achieved in

  • 36.9 percent of the control group
  • 43.7 percent of those given carboplatin

Of the participants with TNBC,

  • 36.9 percent in the control group achieved pCR
  • 53.2 percent of those given carboplatin achieved pCR

Of the participants with HER2-positive breast cancer,

  • 36.8 percent in the control group achieved pCR
  • 32.8 percent of those given carboplatin achieved pCR

Rates of pCR weren’t as high as the researchers expected in the treatment group or the control group. But adding carboplatin had a big impact on pCR for women with TNBC. It did not, however, improve pCR for women with HER2-positive disease.

Women given carboplatin were more likely to stop treatment than women in the control group. Some of the side effects experienced at significantly higher rates by the treatment group were low red and white blood cell count, low blood platelet count and diarrhea. Side effects were less frequent when the dose of carboplatin was lowered.

Limitations

Bevacizumab, the targeted therapy given to study participants with TNBC, is approved for metastatic breast cancer treatment in Germany, where this study took place. But the medicine’s approval for treating metastatic breast cancer in the U.S. was revoked by the FDA in 2011. It is not easily available for metastatic or early-stage disease in the U.S., and insurance might not cover it.

What This Means for You

If you’re going through treatment for triple-negative breast cancer, you may feel there are fewer options for you than there are for people with other kinds of breast cancer. Though this study focused on treatment given before surgery, research like this may give you hope about the future of TNBC treatment.

These researchers suggest that future studies look more closely at how often, and at what dose, carboplatin should be taken when added to a combination cancer treatment given before surgery. The addition of carboplatin may not benefit all patients with TNBC and has significant side effects. Adding this drug probably should not yet be considered standard, even for TNBC patients.

If you’re newly diagnosed, talk with your doctor about pre-surgery treatment and if it might be part of your care plan.

If you’re interested in participating in current trials, talk to your doctor and visit  ClinicalTrials.gov to see what studies are happening now and if you may be eligible.

For more information, read our Guide to Understanding Triple-Negative Breast Cancer.

Von Minckwitz, Gunter, Schneeweiss, Andreas, Loibl, Sibylle et al. Neoadjuvant carboplatin in patients with triple-negative and HER2-positive early breast cancer (GeparSixto; GBG 66):  a randomised phase 2 trialThe Lancet. May 1, 2014; doi:10.1016/S1470-2045(14)70160-3.

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