SOURCES: Sara Tolaney, M.D., M.P.H., attending physician, medical oncology, Dana-Farber Cancer Institute, Boston; Paula Klein, M.D., assistant professor, medicine, hematology and medical oncology, Mount Sinai Icahn School of Medicine, New York City; Charles Shapiro, M.D., co-director, Dubin Breast Center, Mount Sinai Hospital, New York City; Jan. 8, 2015, New England Journal of Medicine
WEDNESDAY, Jan. 7, 2015 (HealthDay News) -- For some women with early breast tumors, lower-dose chemotherapy and the drug Herceptin may help ward off a cancer recurrence, a new study suggests.
Experts said the findings, published in the Jan. 8 New England Journal of Medicine, could offer the first standard treatment approach for women in the early stages of HER2-positive breast cancer.
HER2 is a protein that helps breast cancer cells grow and spread, and about 15 to 20 percent of breast cancers are HER2-positive, according to the U.S. National Cancer Institute.
Herceptin (trastuzumab) -- one of the newer, so-called "targeted" cancer drugs -- inhibits HER2. But while Herceptin is a standard treatment for later-stage cancer, it wasn't clear whether it helps women with small, stage 1 breast tumors that have not spread to the lymph nodes.
Women with those cancers have a relatively low risk of recurrence after surgery and radiation -- but it's high enough that doctors often offer chemotherapy and Herceptin as an "adjuvant," or additional, therapy, explained Dr. Sara Tolaney, of the Dana-Farber Cancer Institute in Boston.
The challenge, Tolaney said, is balancing the potential benefits against the side effects. So for the new study, her team tested a low-intensity chemo regimen -- 12 weeks of a single drug, called paclitaxel -- plus Herceptin for one year.
The researchers found that women who received the drugs were highly unlikely to see their breast cancer come back over the next three years. Of the 406 study patients, less than 2 percent had a recurrence.
There was no control group that did not receive chemo and Herceptin for comparison. But the results are "better than expected," said Dr. Charles Shapiro, co-director of the Dubin Breast Center at Mount Sinai Hospital in New York City.
Shapiro, who was not involved in the study, said it's still not clear what the benefits could be in the longer term.
"Three years of follow-up is short," he said. "Time will tell if there are late recurrences."
In other studies of women with small breast tumors (up to 1 inch across), recurrence rates over five years have ranged widely -- from 5 to 30 percent, Tolaney said.
"With the regimen used in this study, there were very few recurrences and low toxicity," Tolaney said. "So it seems like a reasonable option."
Another oncologist not involved in the study agreed. "This is certainly an option for discussion," said Dr. Paula Klein, also of Mount Sinai.
But that discussion does need to cover the downsides, too, Klein added.
Herceptin is not an easy regimen. It's given by IV, usually once a week for a year, and the common side effects include fever, nausea, vomiting and infection.
There can also be more serious risks. Herceptin can damage the heart, sometimes leading to potentially life-threatening cardiomyopathy (an enlarged heart) or heart failure, where the muscle begins to lose its pumping ability.
In this study, two women developed heart failure. Their heart function normalized once they stopped Herceptin, Tolaney said.
Another issue is price. The one-year course of Herceptin costs roughly $64,000, according to Genentech, the company that makes the drug and funded the current study.
Still, Shapiro said, the shorter-term effects for women with stage 1 cancer appear "exceedingly favorable."
One question for future studies, he added, is whether those patients can benefit from Herceptin alone, and forgo the chemo.
The American Cancer Society has more on treating HER2-positive breast cancer.