Phase II Study of Neoadjuvant Chemotherapy of Breast Cancer

Neoadjuvant chemotherapy has been used for years to treat patients with breast cancer whose primary tumors are too large to allow for breast conservation surgery [1]. Reduction in size of the primary tumor with neoadjuvant chemotherapy has made possible the use of lumpectomies instead of mastectomies in a large fraction of these cases. In the past this was the major objective of neoadjuvant chemotherapy for breast cancer, but more recently the focus has changed and the goals have expanded [2]to include: 1- determination of the chemosensitivity of the tumor so that subsequent chemotherapy can be modified accordingly. 2- to prolong disease free survival . 3- to prolong survival.

So far there has been no consistent improvement in survival using this approach, although two recent studies suggest that a survival benefit might actually occur[3, 4]. However, there is consensus that patients who receive neoadjuvant chemotherapy and who achieve a "pathological CR", meaning that no tumor is found at time of definitive tumor resection, have experienced longer survival[5-8]. Perhaps with a more active neoadjuvant combination a significantly higher pathological CR rate can be obtained, and thus longer survival achieved.

Most neoadjuvant regimens that have been used in the past have only included induction with 3-4 courses of an anthracycline based regimen without a Taxane, followed by surgery and further chemotherapy subsequently. However, the incorporation of docetaxel after an anthracycline-based regimen (Aberdeen and NSABP-B27 protocols) [4, 9]led to better clinical response, subsequently to better breast conservation and more important, an increase in the pathological complete response rate. In the NSABP-B-27 study, 2,411 patients with operable primary breast cancer were randomly assigned to one of three treatment arms: a) four cycles of preoperative AC followed by surgery. b) four cycles of preoperative AC followed by four cycles of preoperative docetaxel (100 mg/m2 IV every 3 weeks), or c) four cycles of AC followed by surgery and subsequently four cycles of postoperative docetaxel. Compared to preoperative AC alone, preoperative AC followed by preoperative docetaxel increased the clinical complete response rate (40.1% v 63.6%; P < .001), the overall clinical response rate (85.5% v 90.7%; P < .001), the pathologic complete response rate (13.7% v 26.1%; P < .001), and the proportion of patients with negative nodes (50.8% v 58.2%; P < .001).

Improvement of relapse free survival has also been observed in the NSABP-B-27 and Aberdeen trials. In the latter trial, improvement in overall survival has also been reported.. A statistically significant improvement in overall survival has not been observed yet in the NSABP-B-27 trial but a longer follow-up of this study is required to better evaluate the impact of including Taxotere (Docetaxel) as part of the neoadjuvant strategy on overall survival of breast cancer. One subgroup of patients in the NSABP-B-27 trial was found in a retrospective analysis to benefit the most. This was the group who achieved a clinical partial response after the first four courses of AC and who received four additional courses of Docetaxel. They benefited from a longer disease free survival.

In another neoadjuvant trial performed at MD Anderson Cancer Center, patients with a pathologic response but with residual tumors >1 cm were randomized to receive postoperative chemotherapy based on their response to preoperative chemotherapy. Those patients who had a change in their chemotherapy experienced a longer survival.