[Effect of axillary lymph node status on prognosis of different types of invasive breast cancer]

Objective: To investigate the effect of axillary lymph node status on the prognosis of different types of invasive breast cancer. Methods: Patients with invasive breast cancer of different molecular subtypes diagnosed in the breast cancer prevention and treatment center of Beijing Cancer Hospital from January 2000 to July 2011 were collected as a historical cohort, and the influence of lymph node status on the prognosis of different types of breast cancer was analyzed. Results: A total of 4 269 female breast cancer patients with molecular subtypes [aged (50.8±11.2) years] information and 3 824 female breast cancer patients with complete axillary lymph node status information [aged (50.5±10.9) years] were included in the study, including 3 135 cases with both molecular subtypes and lymph node status information. The 10-year event free survival (EFS) rates of hormone receptor (HR)⁺/human epidermal growth factor receptor-2(HER2)^-, HR^-/HER2^-and HER2⁺were 82.2%, 79.0% and 76.8%, respectively; the 10-year overall survival (OS) rates were 88.1%, 83.1% and 84.4%, respectively, and the differences of 3 molecular subtypes in EFS and OS were statistically significant (both P<0.001). The 10-year EFS rate of lymph node positive and negative patients was 68.8% and 88.2%, respectively; the 10-year OS rate was 76.7% and 92.5%, respectively, and the differences of lymph node status in EFS and OS were statistically significant (both P<0.001). In lymph node negative subgroup, 3 subtypes showed similar EFS and OS rate (both P>0.05); In lymph node positive subgroup, 3 subtypes showed significantly different EFS and OS (both P<0.05). No modification effect was detected of lymph node status on the correlation of molecular subtypes and EFS, DDFS and OS(all P_interactive>0.1). Conclusions: Different molecular subtypes of breast cancer have different prognosis. Compared with molecular subtype, lymph node status may be a more important prognostic factor.