In a new study, women with relatively small, HER2-positive breast tumors who received a combination of lower-intensity chemotherapy and a targeted therapy following surgery or radiation therapy were very unlikely to have the cancer recur within a few years of treatment, investigators at Dana-Farber Cancer Institute and other research centers will report at the 2013 San Antonio Breast Cancer Symposium.
The findings offer, for the first time, a set of standard treatment guidelines for recurrence prevention in this group of patients. Previous studies of chemotherapy plus targeted therapy in women with HER2-positive breast cancer that hadn't spread to nearby lymph nodes included few patients whose tumors were comparatively small (less than 3 cm in diameter). [Breast cancers are deemed HER2-positive if their cells have surplus human epidermal growth factor receptors on their surface, making them extra-sensitive to signals to grow and divide.]
"Smaller, HER2-positive, node-negative [no sign of spread to the lymph nodes] breast cancers are thought to have a high-enough chance of recurring that many doctors have offered patients a combination of chemotherapy and Herceptin [a targeted therapy] to reduce that risk," says the study's senior author, Eric Winer, MD, chief of the division of Women's Cancers in the Susan F. Smith Center for Women's Cancers at Dana-Farber. "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."
Because of the sometimes difficult side effects of the conventional drug regimens against recurrence – which can include the chemotherapy drugs adriamycin, taxotere, and carboplatin, plus Herceptin – investigators opted for a less harsh combination of the chemotherapy agent paclitaxel and Herceptin. The study enrolled 406 patients with HER2-positive, node-negative breast tumors smaller than 3 cm. They were treated with the drug combination for 12 weeks, followed by nine months of Herceptin alone.
After a median follow-up of 3.6 years, only two or three of the study participants experienced a recurrence of their cancer – accounting for less than 2 percent of the entire group – of developed other health problems.
"The findings suggest that for many women with this type of breast cancer, this regimen should be considered one of the standard strategies for recurrence prevention," Winer remarks.