Aims: We analysed the results of regional community practice to determine the prognosis of axillary lymph-node micrometastases in women with breast cancer.
Methods: Patient data were retrieved from the population-based Eindhoven Cancer Registry in The Netherlands. Between 1975 and 1997, 10,111 patients were diagnosed as having invasive breast cancer. We compared three subgroups: patients without axillary involvement (the pN0 group), patients with axillary micrometastasis (< or = 2 mm, the pN1a group), and patients with a macro metastasis in only one lymph node (> 2 mm, the pN1 group). Follow-up was completed until April 2002.
Results: The relative risk (RR) of dying comparing the pN1a group and the pN1 group to the pN0 group was 1.32 and 1.34, respectively. Excluding the adjuvantly treated patients, the RR of dying was 1.51 and 1.91, respectively for the pN1a group and the pN1 group vs. the pN0 group.
Conclusion: This outcome data of nearly 25 years of community practice show that breast cancer patients with axillary lymph node micrometastasis have a significantly worse survival rate than those without independent of age or tumour size. Adjuvant systemic therapy should be contemplated when treating these patients.