Prognostic value of isolated tumour cells in sentinel lymph nodes in early-stage breast cancer: a prospective study

BACKGROUND: The prognostic significance of isolated tumour cells (ITCs) in the sentinel nodes (SNs) is controversial in early breast cancer, and some centres have abandoned immunohistochemistry to detect ITCs. METHODS: Patients with unilateral pT1N0 breast cancer, operated between February 2001 and August 2005 at a university hospital were included in this prospective, population-based cohort study. Survival of 936 patients with or without isolated tumour cells (ITC) in their SNs were compared with the log-rank test and Cox regression analysis. RESULTS: Eight hundred sixty one (92.0%) patients were ITC-negative (pN0i−) and 75 (8.0%) ITC-positive (pN0i+). Patients with ITC-positive cancer received more frequently adjuvant systemic therapies than those with ITC-negative cancer. The median follow-up time was 9.5 years. Ten-year distant disease-free survival was 95.3% in the pN0i− group and 88.8% in the pN0i+ group (P = 0.013). ITCs were an independent prognostic factor in a Cox regression model (HR = 2.34, 95% CI 1.09–5.04; P = 0.029), together with tumour Ki-67 proliferation index and diameter. ITCs were associated with unfavourable overall survival (P = 0.005) and breast cancer-specific survival (P = 0.001). CONCLUSIONS: We conclude that presence of ITCs in the SNs is an adverse prognostic factor in early small node-negative breast cancer, and may be considered in the decision-making for adjuvant therapy.