A small, early study suggests that a combination of the targeted therapy Herceptin (chemical name: trastuzumab) and the chemotherapy medicine Taxol (chemical name: paclitaxel) seemed to reduce the risk of recurrence (the cancer coming back) of small HER2-positive breast cancers that hadn’t spread to the lymph nodes.
The study, “A phase II study of adjuvant paclitaxel (T) and trastuzumab (H) (APT trial) for node-negative, HER2-posiitve breast cancer (BC),” was presented on Dec. 11, 2013 at the 2013 San Antonio Breast Cancer Symposium.
HER2-positive cancers have too many copies of the HER2/neu gene, which make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that encourage the cancer to grow and spread. About one out of every four breast cancers is HER2-positive.
Herceptin works by attaching to the HER2 protein and blocking it from receiving growth signals. Herceptin, which is given intravenously, is approved by the U.S. Food and Drug Administration (FDA) to:
- treat advanced-stage HER2-positive breast cancers
- lower the risk of recurrence of early-stage HER2-positive breast cancers with a high risk of recurrence
A newer form of Herceptin, Herceptin Hylecta (chemical name: trastuzumab and hyaluronidase-oysk), can be given as an injection.
Taxol, a taxane chemotherapy, works by interfering with the ability of cancer cells to divide. Taxol usually is given in combination with other medicines and is used after surgery to:
- reduce the risk of early-stage breast cancer coming back
- treat advanced-stage breast cancer after it stops responding to standard chemotherapy therapy regimens that include an anthracycline
Taxol is given intravenously.
Treatments given after surgery to reduce the risk of recurrence are called adjuvant treatments.
While Herceptin and chemotherapy are commonly used to treat larger HER2-positive breast cancers that have a high risk of recurrence, there is no current standard treatment for small HER2-positive breast cancers with a low risk of recurrence. Some of these small cancers aren’t treated with Herceptin at all and others are treated with Herceptin and several other chemotherapy medicines.
"Smaller, HER2-positive, node-negative breast cancers are thought to have a high enough chance of recurring that many doctors have offered patients a combination of chemotherapy and Herceptin to reduce that risk," said Eric Winer, M.D., chief of the division of Women's Cancers in the Susan F. Smith Center for Women's Cancers at the Dana-Farber Cancer Institute and senior author of the study. Dr. Winer also is a member of the Breastcancer.org Professional Advisory Board. "But, as this approach hadn't been tested in many women with smaller tumors, we lacked a standard approach to preventing cancer recurrence in these women."
In the APT trial, the researchers wanted to know if a combination of Herceptin and just one chemotherapy medicine, Taxol, would offer benefits to women diagnosed with small HER2-positive breast cancers that hadn’t spread to the lymph nodes and had a low risk of recurrence. This combination is a more aggressive treatment than not using Herceptin, but less aggressive than using Herceptin and more than one chemotherapy medicine.
The APT trial was a phase II trial, which means it was looking at how effective the new treatment is. Phase II trials are usually small and the results are considered early results. If the results are promising, the new treatment will probably go on to a phase III trial. Phase III trials are usually large and are the last step a new treatment goes through before the FDA considers approving it for general use.
About 400 women diagnosed with HER2-positive breast cancer were in the APT trial. All the cancers were smaller than 3 cm and none of the cancers had spread to the lymph nodes. About 60% of the cancers also were estrogen-receptor-positive.
The women received Taxol and Herceptin for 12 weeks, followed by 9 months of Herceptin alone. The researchers wanted to know how long the women lived without the cancer coming back (disease-free survival).
After about 3 years of follow-up, 98.7% of the women were alive and hadn’t had the cancer come back. This means that only 1.3% of the women had the cancer come back.
Both Herceptin and Taxol can cause heart problems, including decreased heart function and heart failure. In the APT trial, only 0.5% of the women had heart problems and these problems went away after the women finished Herceptin treatment. Other side effects in the APT trial included:
- neuropathy (4% of the women)
- low white blood cell count (4% of the women)
- liver problems (3% of the women)
- fatigue (2% of the women)
While more research is needed, the results of this study are very encouraging and may help set a standard of care for women diagnosed with small, HER2-positive breast cancer that hasn’t spread to the lymph nodes.
If you’ve been diagnosed with HER2-positive breast cancer that is smaller than 3 cm and hasn’t spread to the lymph nodes, you and your doctor will consider the characteristics of the cancer, your unique situation, any other health issues you have, and your personal preferences when creating your treatment plan. Ask your doctor why Herceptin is or isn’t recommended for you after surgery and how that decision was made. You also may want to talk to your doctor about this study.
Using the most complete and accurate information possible, you and your doctor can develop a treatment plan that makes the most sense for you. And stay tuned to Breastcancer.org for the latest information on the standard of care for small HER2-positive breast cancers.
Editor’s Note: This article was updated with information about Herceptin Hylecta, which the FDA approved on Feb. 28, 2019.