Response-guided neoadjuvant chemotherapy appears to improve disease-free survival and overall survival in early breast cancer, particularly in hormone receptor–positive tumors, according to the results of a study published in the Journal of Clinical Oncology.
Effective treatment of early breast cancer requires both local and systemic therapy. Local therapy consists of surgery and/or radiation and is directed at destroying any cancer cells in or near the breast. Systemic therapy is directed at destroying cancer cells throughout the body, and may include chemotherapy, targeted therapy, or hormonal therapy. Adjuvant therapy refers to systemic therapy administered after surgery, whereas neoadjuvant therapy refers to systemic therapy delivered prior to surgery. The goal of neoadjuvant therapy is to shrink the cancer before it is surgically removed.
Researchers conducted a study that included 2,072 patients with early breast cancer. Patients received neoadjuvant therapy with two cycles of TAC (docetaxel, doxorubicin, and cyclophosphamide). After the initial two cycles, early responders were randomly assigned to TAC x 6 (four additional cycles of TAC) or TAC x 8 (six additional cycles of TAC). Early non-responders were randomly assigned to TAC x 6 or TAC-NX, which referred to four cycles of NX (vinorelbine/capecitabine). TAC x 8 and TAC-NX were considered “response-guided therapy.” No patients received Herceptin (trastuzumab) during neoadjuvant or adjuvant treatment.
After a median follow-up of 62 months, disease-free survival was significantly longer among early responders who received TAC x 8 compared with those who received TAC x 6. In early non-responders disease-free survival was significantly longer in those who received TAC-NX compared with those who received TAC x 6. Disease-free survival was similar in the two response-guided groups and shorter in the two groups receiving TAC × 6, particularly in early non-responders. Overall, disease-free survival was significantly longer in the response-guided groups than in the conventional groups combined.
Response-guided therapy was associated with a significant but marginal overall survival benefit compared with conventional therapy. Disease-free survival was longer after response-guided chemotherapy in all hormone receptor-positive tumors, but not in hormone receptor-negative tumors. Pathologic complete response did not predict many of the observed survival effects, but was significantly predictive of improved disease-free survival in triple-negative, HER2-positive (nonluminal), and luminal B (HER2-negative) tumors.
The researchers concluded that response-guided neoadjuvant chemotherapy might improve survival and is most effective in hormone receptor-positive tumors. If these results are confirmed, this approach could provide “a clinically meaningful advantage for the neoadjuvant over the adjuvant approach in early breast cancer.”
Von Minckwitz G, Blohmer JU, Costa SD, et al. Response-guided neoadjuvant chemotherapy for breast cancer. Journal of Clinical Oncology. 2013; 31(29): 3623-3630.