SAN ANTONIO—The sequential use of docetaxel(Drug information on docetaxel) (Taxotere) after Adriamycin (doxorubicin)/cyclophosphamide (AC) as a neoadjuvant regimen in primary operable breast cancer essentially doubles the rate of pathologic complete responses (CRs), according to final response data from the National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-27.

NSABP B-27, reported at the 24th Annual San Antonio Breast Cancer Symposium (abstract 5), evaluated neoadjuvant AC (60/600 mg/m² every 3 weeks) and docetaxel (100 mg/m² every 3 weeks) in 2,411 patients with large operable breast tumors.

Patients were randomized to four cycles of AC followed by surgery (group 1); four cycles of AC followed by four cycles of docetaxel and then surgery (group 2); or four cycles of AC, then surgery, followed by four cycles of docetaxel (group 3). For purposes of the response rate analyses, groups 1 and 3 were combined into the AC group and compared with group 2, the AC/T group.

The sequential use of docetaxel after preoperative AC increased the breast tumor pathologic complete response rate by 87%, clinical complete response rate by 60%, and lymph-node-negative status by 15%, reported Harry D. Bear, MD, PhD, professor of surgery, Virginia Commonwealth University, Richmond.

The prior NSABP B-18 trial showed improved survival in patients who achieved a pathologic complete response; however, in that trial, neoadjuvant AC produced only a 13% pathologic complete response rate. The aim of B-27 was to determine whether the addition of a taxane to AC neoadjuvant therapy would improve pathologic complete response rates and multiple outcomes.

Survival analyses will be conducted later, but Dr. Bear commented on the potential effect. "We know that pathologic response to a given regimen predicts overall outcome in terms of survival. But we don’t know whether that is because of the treatment or the biology of the tumor. This trial will be one of the first to answer the question, ‘If you change the treatment to increase the response rate, will you also get an improved survival?’

If the docetaxel group has a better survival, he said, "this will tell us that local response is truly a surrogate for outcome in terms of survival. We can then use this in subsequent trials as an endpoint. I am very optimistic, but we don’t yet have the data on long-term follow-up."