[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.目的： 分析临床T1～3N1M0期乳腺癌患者经新辅助化疗(NAC)和改良根治术后达到腋窝淋巴结病理阴性(ypN0)患者术后放疗的价值和预后。 方法： 回顾性分析1999—2013年中国医学科学院肿瘤医院收治的185例临床诊断为T1～3N1M0期乳腺癌患者的临床资料，所有患者均完成NAC和改良根治术，术后达ypN0。89例行术后放疗，96例未行放疗。Ⅱ期患者101例，Ⅲ期患者84例。采用Kaplan-Meier法计算局部区域复发率、远处转移率、无病生存率和总生存率，并行Log rank检验，单因素分析临床特征和治疗对患者预后的影响。 结果： 全组患者的5年局部区域复发率、远处转移率、无病生存率和总生存率分别为4.5%、10.4%、86.6%和97.1%。放疗组和未放疗组患者的5年局部区域复发率分别为1.1%和7.5%，差异无统计学意义(P＝0.071)；5年远处转移率分别为5.1%和15.0%，差异有统计学意义(P＝0.023)；5年无病生存率分别为95.0%和79.0%，差异有统计学意义(P＝0.008)；5年总生存率分别为100.0%和94.5%，差异无统计学意义(P＝0.089)。单因素分析结果显示，有无脉管瘤栓是影响患者5年局部区域复发率的主要因素(P＝0.001)，年龄和有无辅助放疗是影响患者5年远处转移率的主要因素(均P<0.05)，有无放疗是影响患者5年无病生存率的主要因素(P＝0.008)，病理T分期、原发灶NAC病理反应是影响患者5年总生存率的主要因素(均P<0.05)。Ⅲ期患者中，放疗组和未放疗组患者的5年局部区域复发率分别为1.9%和14.4%，差异有统计学意义(P＝0.041)；5年无病生存率分别为91.9%和67.4%，差异有统计学意义(P＝0.022)。Ⅱ期患者中，放疗组和未放疗组患者的5年远处转移率分别为0和11.5%，差异有统计学意义(P＝0.044)；5年无病生存率分别为100.0%和84.9%，差异有统计学意义(P＝0.023)。 结论： 临床T1～3N1M0期乳腺癌NAC和改良根治术后达到ypN0患者的的局部区域复发率较低，术后放疗能明显降低远处转移率并提高无病生存率，并且可以降低临床Ⅲ期患者的局部区域复发率。Ⅲ期患者需要术后放疗，Ⅱ期患者的放疗价值需要进一步研究。.