Prognostic implications of pathological lymph node status after preoperative chemotherapy for operable T3N0M0 breast cancer

Background: Although preoperative chemotherapy has become the standard of Care for inoperable locally advanced breast cancer, its role for downstaging resectable primary tumors is still evolving. The purpose of this study was to determine whether the prognostic information from an axillary node dissection in patients with clinical T3N0 breast cancer was altered by preoperative chemotherapy compared with surgery de novo. Methods: Between 1976 and 1994, 91 patients with clinically node-negative operable T3 breast cancer received doxorubicin-based combination chemotherapy on protocol at one institution. Fifty-three patients received both preoperative and postoperative chemotherapy (PreopCT), and 38 received postoperative chemotherapy only (PostopCT). All patients underwent axillary lymph node dissection as part of their definitive surgical treatment. There were no differences between the PreopCT and PostopCT groups in median age (51 vs. 49 years), median tumor size at presentation (6 cm vs. 6 cm), tumor grade, or estrogen receptor status (estrogen receptor negative 38% vs. 32%). The median follow-up time was 7 years. Results: Patients in the PreopCT group had fewer histologically positive lymph nodes (median, 0 vs. 3, P < .01), and a lower incidence of extranodal extension (19% vs. 42%, P = .02). By univariate analysis, the number of pathologically positive lymph nodes (P < .01) and extranodal extension (P < .01) were predictors of disease-specific survival in PreopCT patients. Multivariate analysis showed that extranodal extension was the only independent prognostic factor in PreopCT patients (P < .01). Overall, PreopCT and PostopCT patients had similar 5-year disease-free survival rates (66% vs. 57%); however, PreopCT patients had worse disease- free (P = .01) and disease-specific survival (P = .04) when survival was compared after adjustment for the number of positive lymph nodes. Furthermore, PreopCT patients with 4-9 positive lymph nodes had a lower 5- year disease-free survival rate than PostopCT patients with 4-9 positive nodes (17 vs. 48%, P =.04). Conclusions: Axillary lymph node status remains prognostic after chemotherapy. Pathologically positive lymph nodes after preoperative chemotherapy are associated with a worse prognosis than the same nodal status before chemotherapy.