Treatment combining low-dose chemotherapy and the targeted drug trastuzumab showed promise in women with early stage breast cancer of a type called HER2-positive, US researchers said Wednesday.
Women receiving the treatment were highly unlikely to see their cancer return, said the study in the New England Journal of Medicine analyzing a regimen that including the chemotherapy agent paclitaxel and the targeted drug under the brand name Herceptin.
Three years after completing the combination therapy, “98.7 percent of the participants were alive and free of invasive breast cancer,” said the study led by researchers at Dana-Farber Cancer Institute in Massachusetts.
The phase II trial involved 406 women whose tumors were smaller than three centimeters and had not spread to their lymph nodes. They were treated with the drug combination for 12 weeks, followed by nine months of Herceptin alone.
“Women with small, HER-2 positive, node-negative breast tumors have a low, but still significant, risk of recurrence of their disease,” said the study’s senior author, Eric Winer, director of the Breast Oncology Program at the Susan F. Smith Center for Women’s Cancers at Dana-Farber.
“This study demonstrates that a combination of lower-intensity chemotherapy and trastuzumab — which is associated with fewer side effects than traditional chemotherapy regimens — is an appealing standard of care for this group of patients.”
Approaches to treating women with HER2-positive breast cancer — which means their cells have extra human epidermal growth factor receptors on their surface — have varied widely but often involve a stronger regimen of chemotherapy with adriamycin and cytoxan followed by paclitaxel and trastuzumab, researchers said.
Until now, Herceptin has been recommended mainly for women with larger tumors, or who are at greater risk of metastasis. Some of the reported side effects have included heart and lung problems and fatal infusion reactions.
Charles Shapiro, co-director of Dubin Breast Center, The Mount Sinai Hospital in New York, said the latest research raises new questions.
“Three years of follow-up is short, and time will tell if there are late recurrences,” he said.
“The take-home message is that, for this group of women with Stage I HER positive tumors, the short outcome is exceeding favorable, and this was achieved using a 12-week course of Taxol. Based on these results the next question is could we eliminate the chemotherapy?”
The research was funded by Genentech, the pharmaceutical company that makes Herceptin, and the breast cancer foundation Susan G. Komen for the Cure.