Prognostic significance of pathological response of primary tumor and metastatic axillary lymph nodes after neoadjuvant chemotherapy for locally advanced breast carcinoma.

PURPOSE: The prognostic significance of pathological response of primary tumor and metastatic axillary lymph nodes after neoadjuvant chemotherapy was assessed in patients with noninflammatory locally advanced breast carcinoma. PATIENTS AND METHODS: Between January 1989 and April 1995, 148 consecutive patients with locally advanced breast carcinoma participated in the study. Of these, 140 fully evaluable patients (67, stage IIIA; 73, stage IIIB) were treated with three courses of 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC), followed by modified radical mastectomy when technically feasible or definitive radiation therapy. The median age was 53 years (range, 26 to 75 years); 55% of patients were postmenopausal.
RESULTS: Objective response was recorded in 99 of 140 patients (71%; 95% confidence interval, 63% to 79%). Complete response occurred in 11 patients (8%), and partial response occurred in 88 patients (63%). No change was recorded in 37 patients (26%), and progressive disease occurred in 4 patients (3%). One hundred and thirty-six patients underwent the planned surgery. Maximal pathological response of the primary tumor (in situ carcinoma or minimal microscopic residual tumor) was observed in 24 (18%); 112 patients (82%) presented minimal pathological response of the primary tumor (gross residual tumor). The number of metastatic axillary nodes after neoadjuvant chemotherapy was as follows: N0, 39 patients (29%); N1-N3, 35 patients (26%); > N3, 62 patients (45%). Considering the initial TNM status, 75% of the patients had decreases in tumor compartment after neoadjuvant chemotherapy. Also, 31% and 23% of patients with clinical N1 and N2, respectively, showed uninvolved axillary lymph nodes. A significant correlation was noted between pathological response of primary tumor and the number of metastatic axillary lymph nodes. Median disease-free survival was 34 months, whereas median overall survival was 66 months. Pathological responses of both primary tumor and metastatic axillary lymph nodes were strongly correlated with disease-free survival and overall survival in univariate analyses. Additionally, in a proportional hazard regression model and in an accelerated failure time model, metastatic axillary lymph nodes significantly influenced both disease-free survival and overall survival, whereas pathological response of primary tumor did so on disease-free survival only.
CONCLUSION: After neoadjuvant chemotherapy, pathological responses of both primary tumor and metastatic axillary lymph nodes had a marked prognostic significance and influenced outcome for patients with locally advanced breast carcinoma. Our results suggest that maximal tumor shrinkage and sterilization of potentially involved axillary nodes may represent a major goal of neoadjuvant chemotherapy. Further studies are warranted to clarify whether these results reflect the therapeutic effect or intrinsic biologic factors of the tumor.