The feasibility of minimally invasive surgery for stage IIA, IIB, and IIIA breast carcinoma patients after tumor downstaging with induction chemotherapy

BACKGROUND. Induction chemotherapy (IC) has become the standard of care for locally advanced breast carcinoma, frequently downstaging both the primary tumor and the axilla, and making patients eligible for less invasive surgical procedures. The usefulness of IC in earlier stage operable breast carcinoma is now being considered. METHODS. This study involved a subset of 129 patients from a series of 174 with T2-3, N0-1, M0 or T1, N1, M0 breast carcinoma (Stage IIA, IIB, or IIIA) who were registered in a prospective IC trial using paclitaxel or a combination of fluorouracil, doxorubicin, and cyclophosphamide (FAC). The subset included patients who had received no preoperative radiation therapy but had completed 3-5 cycles of induction chemotherapy and had undergone a Level I-II axillary lymph node dissection. The objective was to evaluate the effectiveness of induction chemotherapy with paclitaxel or FAC in downstaging the primary tumor and axillary metastases in these early stage breast carcinoma patients. RESULTS. The median initial tumor size was 4 cm (range, 0.6-10.0); after IC, tumor size was downstaged to 1.6 cm (range, 0.0-7.0) (P < 0.0001). Clinical response to IC was complete in 24% of patients and partial in 36%. Primary tumor shrinkage was similar with paclitaxel and FAC. Among patients clinically classified as N1, 34% became histologically negative and 38% had only 1-3 positive lymph nodes after induction chemotherapy. CONCLUSIONS. IC with paclitaxel or FAC resulted in effective downstaging of primary tumors and axillary metastases in patients with Stage IIA, IIB, and IIIA breast carcinoma. However, a significant proportion of patients still had residual but low volume microscopic disease; such disease status may allow minimally invasive surgical approaches to locoregional therapy. (C) 2000 American Cancer Society.