T3 disease at presentation or pathologic involvement of four or more lymph nodes predict for locoregional recurrence in stage II breast cancer treated with neoadjuvant chemotherapy and mastectomy without radiotherapy

Purpose: To help define the clinical and pathologic predictors of locoregional recurrence (LRR) in breast cancer patients treated with neoadjuvant chemotherapy and mastectomy without radiotherapy for early-stage disease. Methods and Materials: We retrospectively reviewed the outcomes of all 132 patients with Stage I or II breast cancer treated in prospective institutional trials with neoadjuvant chemotherapy and mastectomy without radiotherapy between 1974 and 2001. The clinical stage (American Joint Committee on Cancer 1988) at diagnosis was I in 5%, IIA in 46%, and IIB in 49% of patients. The median age at diagnosis was 49 years. All patients were treated with either a doxorubicin-based neoadjuvant regimen or single-agent paclitaxel. The total LRR rates were calculated by the Kaplan-Meier method, and comparisons were made with two-sided log-rank tests. The median follow-up was 46 months. Results: The actuarial LRR rate at both 5 and 10 years was 10%. Factors that correlated positively with LRR included clinical Stage T3N0 (p = 0.0057), four or more positive lymph nodes at surgery (p = 0.0001), age ≤40 years at diagnosis (p = 0.0001), and no use of tamoxifen. In the patients who did not receive tamoxifen, estrogen receptor-positive disease correlated positively with LRR (p = 0.0067). The 5-year LRR rate for the 42 patients with clinical Stage T1 or T2 disease and one to three positive lymph nodes at surgery was 5% (only two events). Conclusion: For patients with clinical Stage II breast cancer, T3 primary disease, four or more positive lymph nodes after chemotherapy, and age ≤40 years old predicted for LRR. For most patients with clinical T1 or T2 disease and one to three positive lymph nodes, the 5-year risk for LRR was low, and the routine inclusion of postmastectomy radiotherapy does not appear to be justified.