[The role of postmastectomy radiotherapy in clinical T1-3N1M0 breast cancer patients with pathological negative lymph nodes after neoadjuvant chemotherapy and mastectomy].

Objective: To analyze the outcomes of clinical T1-3N1M0 breast cancer patients with pathological negative axillary lymph nodes (ypN0) after neoadjuvant chemotherapy (NAC) and mastectomy, and investigate the role of postmastectomy radiotherapy (PMRT). Methods: A total of 185 patients with clinical T1-3N1M0 breast cancer treated between 1999 and 2013 were retrospectively reviewed. All patients were treated with NAC and mastectomy, and achieved ypN0. Of them, 89 patients received additional PMRT and 96 patients did not. 101 patients had clinical stage Ⅱ disease. 84 patients had clinical stage Ⅲ disease. The rates of locoregional recurrence (LRR), distant metastasis (DM), disease-free survival (DFS), and overall survival (OS) were calculated using the Kaplan-Meier method, and differences were compared using the log-rank test. Univariate analysis was used to interpret the impact of clinical features and treatment on patients' outcome. Results: The 5-year rates of LRR, DM, DFS, and OS for all patients were 4.5%, 10.4%, 86.6%, and 97.1%, respectively. For patients with and without PMRT, the 5-year LRR rates were 1.1% and 7.5% (P=0.071), the 5-year DM rates were 5.1% and 15.0% (P=0.023), the 5-year DFS rates were 95.0% and 79.0% (P=0.008), and the 5-year OS rates were 100.0% and 94.5% (P=0.089) respectively. In univariate analysis, lymph-vascular space invasion (LVSI) was poor prognostic factor of LRR (P=0.001), < 40 years old and lack of PMRT was a poor prognostic factor for DM (P<0.05), lack of PMRT was a poor prognostic factor for DFS (P=0.008), primary lesion residual and mild-moderate pathological response to NAC were poor prognostic factors for OS (P<0.05). In the subgroup of Stage Ⅲ disease, for patients with and without PMRT, the 5-year LRR rates were 1.9% and 14.4% (P=0.041), the 5-year DFS rates were 91.9% and 67.4% (P=0.022), respectively. In the subgroup of Stage Ⅱ disease, for patients with and without PMRT, the 5-year DM rates were 0 and 11.5% (P=0.044), the 5-year DFS rates were 100.0% and 84.9% (P=0.023), respectively. Conclusions: The LRR rate of clinical T1-3N1M0 breast cancer patients who achieved ypN0 after NAC and mastectomy was low. PMRT decreased the DM rate and increased DFS rate in all patients, and significantly decreased the LRR rate in Stage Ⅲ disease. PMRT should be considered for patients with Stage Ⅲ disease, and further research is warranted to investigate the benefit of PMRT for Stage Ⅱ disease.

[Prognostic value of sequencing of radiotherapy and chemotherapy following breast-conserving surgery for patients with breast cancer].

Objective: To evaluate the prognostic value of sequencing of adjuvant radiotherapy and chemotherapy following breast-conserving surgery for patients with breast cancer. Methods: A total of 1 154 patients withT1-2N0-3M0 breast cancer retrospectively reviewed. All patients received sequential radiotherapy and chemotherapy following breast-conserving surgery. Among them, 603 patients received radiotherapy first and 551 patients received chemotherapy first. Log-rank tests were used to determine significance of disease-free survival (DFS) and overall survival (OS) rates in the Kaplan-Meier curve. Results: The 5-year DFS and OS rates for all patients were 93.0% and 97.8%. The 5-year OS rate was 98.6% in the radiotherapy first group and 96.4% in the chemotherapy first group (P=0.191), and the corresponding DFS rate was 92.7% and 93.2% (P=0.430), respectively. Among the patients with Luminal A subtype, the 5-year OS rate was 99.6% in the radiotherapy first group and 97.8% in the chemotherapy first group (P=0.789). Among the patients with Luminal B subtype, the 5-year OS rate was 94.2% and 96.0%, respectively (P=0.680). Among the patients with triple negative breast cancer, the 5-year OS rate was 100% and 90.9%, respectively, with statistically significant differences (P=0.019). Among the patients with HER-2 positive breast cancer, The 5-year DFS rate was 80.1% and 100%, respectively (P=0.045). Conclusions: The OS and DFS rates in the chemotherapy first group are not significantly different from those of radiotherapy first group after breast-conserving surgery. Patients with HER-2 positive breast cancer in chemotherapy first group have a much higher DFS rate than that of radiotherapy first group, whereas patients with triple negative breast cancer in radiotherapy first group have a better OS rate than that of chemotherapy first group. Further research is warranted to investigate the benefit of different molecular types in different sequencing of radiotherapy and chemotherapy after breast-conserving surgery.