Chemo plus herceptin boost breast cancer survival

By David Liu

A new study led by researchers at the Mayo Clinic campus in Jacksonville, Fla suggests that patients with HER2 positive breast cancer would be better off being treated with a combination of chemotherapy and herceptin.

It is uncommon right now to use the combo in many countries to treat women with Her2 positive breast cancer, which accounts for 20 to 25 percent of all cases.  But the new study finds that the combo did a better job at extending breast cancer survival rate than chemotherapy alone or use of herceptin after chemo.

Edith Perez, M.D. of the Mayo Clinic campus presented the findings at the Cancer Therapy & Research Center-American Association for Cancer Research (CTRC-AACR) 2009 San Antonio Breast Cancer Symposium.

In the U.S., herceptin is approved for use together with adjuvant chemotherapy (concurrent use) or after the chemotherapy (sequential use), according to Dr. Perez.

The study, the NCCTG clinical trial N9831, was partly reported in 2005 in the New England Journal of Medicine.  This current report covered the complete data set derived from the trial of about 2,000 women who had surgery to treat stage 1-II invasive HER2 positive breast cancer.

The chemotherapy used in the phase III randomized clinical trial was doxorubicin and cyclophosphamide then paclitaxel given for six months. Herceptin was administered for one year.

The researchers found the five-year disease-free survival defined as no cancer recurrence for women who received chemotherapy alone was 72 percent compared to 80 percent for those who received chemo and later herceptin.  The cases of death or cancer recurrence were 222 for the former and 164 for the latter.

In comparison, the five year disease-free survival rate for the group of women who received both chemotherapy and herceptin concurrently was 84 percent.

"The study demonstrated that adding Herceptin clearly improves disease-free survival, with improvement if given after chemotherapy, but even more improvement if started concurrent with taxane-based chemotherapy," Dr. Perez said.

"So, our recommendation for practice and regulatory agencies around the world is that Herceptin be given concurrent with adjuvant chemotherapy."

Another study also presented at the conference shows that a new antibody drug called T-DM1 helped shrink or halt the growth of metastatic HER2 positive breast cancer in many patients whose disease became resistant to standard therapies.

Ian Krop. MD, PhD, principal investigator of the study, reported that the hybrid agent shrank tumors by 30 percent or more in 40 percent of women with HER2-positive cancers and 13 percent had stable disease for at least six months. The median time before the cancer progressed was 7.3 months, according to a press release. 

Breast cancer is diagnosed in more than 175,000 Americans each year in the U.S. and the disease kills about 45,000 women annually.

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