Prognostic value of isolated tumor cells and micrometastases of lymph nodes in early-stage breast cancer: A French sentinel node multicenter cohort study

To define the prognostic value of isolated tumor cells (ITC), micrometastases (pN1mi) and macrometastases in early stage breast cancer (ESBC). We conducted a retrospective multicenter cohort study at 13 French sites. All the eligible patients who underwent SLNB from January 1999 to December 2008 were identified, and appropriate data were extracted from medical records and analyzed. Among 8001 patients, including 70% node-negative (n = 5588), 4% ITC (n = 305), 10% pN1mi (n = 794) and 16% macrometastases (n = 1314) with a median follow-up of 61.3 months, overall survival (OS) and recurrence-free survival (RFS) rates at 84 months were not statistically different in ITC or pN1mi compared to tumor-free nodes. Axillary recurrence (AR) was significantly more frequent in ITC (1.7%) and pN1mi (1.5%) compared to negative nodes (0.6%). Survival and AR rates of single macrometastases were not different from those of ITC or pN1mi. In case of 2 macrometastases or more, survival rates decreased and recurrence rates increased significantly. Micrometastases and ITC do not have a negative prognostic value. Single macrometastases might have an intermediate prognostic value while 2 macrometastases or more are associated with poorer prognosis.