Prognostic value of lymph node micrometastases in breast cancer: A multicenter cohort study

Abstract

Background: To evaluate the prognostic meaning of lymph node micrometastases in breast cancer patients. Methods: Between January 2000 and January 2003, 1411 patients with a cT1-2N0 invasive breast carcinoma underwent surgery in 7 hospitals in the Netherlands. Sentinel lymph node biopsy was done in all patients. Based on lymph node status, patients were divided into 4 groups: pN0 (n = 922), pN 1micro (n = 103), pN1a (n = 285), and pN≥1b (n = 101). Median follow-up was 6.4 years. Results: At the end of follow-up, 1121 women were still alive (79.4%), 184 had died (13.0%), and 106 were lost to follow-up (7.5%). Breast cancer recurred in 244 patients: distant metastasis (n = 165), locoregional relapse (n = 83), and contralateral breast cancer (n = 44). Following adjustment for possible confounding characteristics and for adjuvant systemic treatment, overall survival (OS) remained comparable for pN0 and pN1micro and was significantly worse for pN1a and pN≥1b (hazard ratio [HR] 1.18; 95% confidence interval [95% CI] 0.58-2.39, HR 2.47; 95% CI 1.69-3.63, HR 4.36; 95% CI 2.70-7.04, respectively). Disease-free survival (DFS) was similar too in the pN0 and pN1micro group, and worse for pN1a and pN≥1b (HR 0.96; 95% CI 0.56-1.67 vs HR 1.64; 95% CI 1.19-2.27, HR 2.95; CI 1.98-4.42). The distant metastases rate also did not differ significantly between the pN0 and pN1micro group and was worse for pN1a and pN≥1b (HR 1.22; 95% CI 0.60-2.49, HR 2.26; 95% CI 1.49-3.40, HR 3.49; CI 2.12-5.77). Conclusions: In breast cancer patients survival is not affected by the presence of micrometastatic lymph node involvement. © 2010 The Author(s).