Combining heavy hitting medications for early stage patients with an aggressive form of breast cancer can shrink the tumor and stop its progression, according to two new studies released Monday in the journal Lancet and Lancet Oncology.
An estimated 20 percent of women with breast cancer have a type known as HER2 positive, which is among the fastest growing and most aggressive.
Therapy agents such as Tykerb or Herceptin are typically used for later stages of the disease when the tumor is considered inoperable. These treatments have been shown to downsize the tumor enough to perform surgery.
The trials, in its third phases, found that even patients in the early stages of the disease -- who are considered operable -- can benefit from these types of medications before undergoing surgery.
The first study, published in The Lancet Oncology, suggests the chemotherapy medication Tykerb is less effective taken on its own compared to Herceptin.
In the other study, researchers at Massachusetts General Hospital in Boston assigned patients in three groups with HER2 positive breast cancer with either the chemotherapy medication Tykerb, Herceptin, or a combination of both medications before undergoing surgery.
The tumors in those who received the combination treatment before surgery were on average 20 percent smaller after six weeks compared to patients who took either of the medications alone, according to the study, which was first presented at the 2010 San Antonio Breast Cancer Symposium. There were far fewer side effects and they were less severe compared to standard chemotherapy.
These studies add to mounting research looking at tackling aggressive tumors early in the process.
"These studies represent a paradigm shift in breast cancer research where you're studying these therapies up front," said Dr. Jose Baselga, chief of oncology at Massachusetts General Hospital, and lead author of the study published in the Lancet. "This will cut down the time significantly of bringing these therapies to the public."
Many experts said that studying these medications given in earlier stages will help researchers see how tumors are responding to various treatments before and after surgery.
Doctors can "get an answer about drugs in early breast cancer in months rather than years, and it takes only a few hundred patients rather than thousands," said Dr. Lisa Carey, medical director of the University of North Carolina Breast Center.
But even though these therapies have been shown to shrink a tumor, no evidence suggests they can improve survival in patients with the disease.
"The ultimate aim of breast cancer treatment is to save lives, not just to achieve responses to treatment," Dr. Michael Gnant and Dr. Guenther Steger, researchers at Medical University of Vienna in Austria wrote in an accompanying editorial to the Lancet study.
Longer term evaluation of patients after surgery may provide that answer, they wrote. Until then, many breast cancer experts say they probably will not prescribe this new combination to patients just yet.
"Many may still be waiting for the [long-term survival] data for this to be done as standard therapy," said Dr. Jennifer Litton, assistant professor in the Department of Breast Medical Oncology at MD Anderson.
Although the combination is not FDA approved for use in patients, Baselga said these late trial results suggest they could change how HER2 positive breast cancer is managed.
"In HER2 positive disease, with no exception, the early results have always resulted in improved disease-free survival," said Baselga. "So while it's nice to have the data, and we will, particularly in this type, the response is as good as it gets."