A very small, early study suggests that a combination of four medicines given BEFORE surgery to treat HER2-positive, early-stage breast cancer may be a good way to weaken and destroy breast cancer cells. Two targeted therapy medicines and two chemotherapy medicines make up the combination:
- Herceptin (chemical name: trastuzumab)
- Tykerb (chemical name: lapatinib)
- Taxotere (chemical name: docetaxel)
- Carboplatin (brand name: Paraplatin)
The results were presented at the 2010 San Antonio Breast Cancer Symposium (SABCS).
Treatment given to weaken and destroy breast cancer BEFORE surgery is called neoadjuvant treatment. Neoadjuvant treatment isn't routinely used to treat early-stage breast cancer, but may be used if the cancer is large or aggressive. In most cases, chemotherapy is the neoadjuvant treatment.
HER2-positive cancers have too many copies of the HER2/neu gene, which make too much of the HER2 protein. HER2-positive breast cancers tend to be aggressive, so doctors may recommend neoadjuvant treatment for them.
Herceptin and Tykerb are both targeted therapies that treat HER2-positive breast cancers by blocking the cancer cells' ability to receive growth signals. Herceptin isn't approved by the U.S. Food and Drug Administration to be used before surgery, but doctors sometimes use it that way. Tykerb also isn't approved to be used before surgery for early-stage breast cancer. Herceptin is given intravenously. Tykerb is a pill taken by mouth.
The chemotherapy medicines Taxotere and carboplatin don't target HER2 proteins, but both are sometimes used before surgery to treat both HER2-positive and HER2-negative breast cancers. Taxotere is a taxane and weakens or destroys cancer cells by interfering with the ability of cancer cells to divide. Carboplatin, a platinum-type chemotherapy, weakens or destroys breast cancer cells by damaging the genetic material in the cells and making it hard for cells to repair any genetic damage.
The results reported come from a larger study on several neoadjuvant treatment combinations for women diagnosed with early-stage, HER2-positive breast cancer. Twenty women got the neoadjuvant combination of Herceptin, Tykerb, Taxotere, and carboplatin. Twelve of the cancers were hormone-receptor-positive and eight were hormone-receptor-negative. Half of the women were older than 50.
Of the 20 women, 18 finished the study. The other two women stopped treatment: one because of severe diarrhea and the other because of infection and anemia (low red blood cell count).
After neoadjuvant treatment, the women had surgery to remove the cancer. The researchers looked at the tissue removed to see how the cancer responded to the neoadjuvant treatment. "Complete pathologic response" is the term researchers use if there are no active cancer cells in the tissue.
Overall, half the women had a complete pathologic response to the combination neoadjuvant treatment:
- 4 of the 12 women (33%) with hormone-receptor-positive breast cancer had a complete pathologic response
- 5 of the 8 women (63%) with hormone-receptor-negative breast cancer had a complete pathologic response
Chemotherapy and targeted therapy medicines can cause serious side effects, including low white blood cell counts (neutropenia, which increases the risk of serious infection), severe diarrhea, and neuropathy (nerve damage in the hands and feet). Particularly serious side effects are classified grade 3 or grade 4.
The most common serious side effect of the neoadjuvant treatment was diarrhea; six women had grade 3 diarrhea. Other serious side effects included grade 3 or grade 4 neutropenia in four women, and grade 3 or grade 4 low blood potassium levels in three women.
While encouraging, these results are early results. More research is needed to better understand and compare the benefits of various neoadjuvant treatment combinations for some women diagnosed with aggressive early-stage breast cancer. This research could lead to new and better ways to improve the prognosis of women diagnosed with early-stage breast cancer. While serious side effects are a major concern, experts believe these usually can be managed and that the treatment benefits outweigh the risks.
If you've been recently diagnosed with HER2-positive breast cancer and haven't had surgery yet, you might want to talk to your doctor about this study and if neoadjuvant treatment might be right for you.