The Relation Between The Number Of Axillary Lymph Node Detection And Disease-Free Survival In Breast Cancer Patients

Objective:The clinical stage of breast cancer is based on the number of axillary lymph node metastasis, which is closely related with the prognosis of patients with breast cancer. We investigated whether the disease-free survival (DFS) of patients with breast cancer was associated with the number and number of the lymph nodes examined.Methods:678 breast cancer Patients who haved treated with axillary lymph node dissection from January 2001 to October 2010 were included into analysis. Statistical analysis was performed using SPSS (Statistical Package for the Social Sciences) Version 16.0. The patient survival curves were estimated using the statistical model of Kaplan and Meier. Survival curves of different subgroups were compared using the log-rank test. For multivariate analysis, we used the Cox regression model.Result:A total of 9195 axillary lymph nodes were detected in 678 breast cancer patients. The average number of lymph nodes was 13.6. The number of detected lymph nodes was or less than 9 in 234 patients. However, in 443 patients, the number was more than 9.There were 380 node-negative patients while 298 patients with positive lymph nodes. The positive rate of axillary lymph nodes was 44.0%. Among these,159 cases were pN1 (23.4%),92 cases were pN2 (13.6%), and 47 cases were pN3 (6.9%). During the follow-up,85 cases occurring live events (12.5%), including 39 cases (5.8%) for local recurrence,40 cases(5.9%) for distant metastases, one case for the contralateral relapse,15 cases death, with 6 cases were the first time event. In total, the 5-year DFS rate was 81.5%. For patients with positive lymph node, the 5-year DFS is 72.6%. For patients with negative lymph node, the 5-year DFS was 88.2%. The 5-year DFS for patients with positive node was significantly lower than that with negative node (P<0.0001).In the negative lymph nodes patients, the 5-year DFS was 90.1% for patients examined less than 9 lymph nodes, and 86.3% for patients examined more than 9 lymph nodes. There was no significant difference between the two group (P=0.203). In the positive lymph nodes patients, the 5-year DFS was 64.8% for patients examined less than 9 lymph nodes, and 78.1% for patients examined more than 9 lymph nodes.There was significantly difference between the two group (P=0.005). By univariate analysis, the ER, PR and HER2 were significant factors influencing the DFS for patients with negative lymph nodes. However, the tumor size, the number of lymph nodes examined, ER, PR and HER2 were significant factors influencing the DFS for patients with positive lymph nodes.By multivariate analysis, the HER2 were significant factors influencing the DFS for patients with negative lymph nodes. However, the number of lymph nodes examined and HER2 were significant factors influencing the DFS for patients with positive lymph nodes.Conclusion:The number of axillary lymph node metastasis is a major impact factor for the 5-years DFS of breast cancer patients postoperatively,increase the number of lymph nodes detected can not improve the 5 years disease-free survival of patients whose lymph node is negative, while patients with nodal involvement gained significantly benefit from these.