Prognostic factors in metastatic breast cancer: a prospective single-centre cohort study in a Finnish University Hospital

OBJECTIVES: Although novel early breast cancer prognostic factors are being continuously discovered, only rare factors predicting survival in metastatic breast cancer have been validated. The prognostic role of early breast cancer prognostic factors in metastatic disease also remains mostly unclear. DESIGN AND SETTING: Prospective cohort study in a Finnish University Hospital. PARTICIPANTS AND OUTCOMES: 594 women with early breast cancer were originally followed. Sixty-one of these patients developed distant metastases during the follow-up, and their primary breast cancer properties, such as tumour size, nodal status, oestrogen receptor (ER) and progesterone receptor expression, grade, proliferation rate, histopathological subtype and breast cancer subtype were analysed as potential prognostic factors for metastatic disease. RESULTS: In multivariate analysis, the presence of lymph node metastases at the time of early breast cancer surgery (HR, 2.17; 95% CI, 1.09–4.31; p=0.027) and ER status (negative vs positive, HR, 2.16; 95% CI, 1.14–4.10; p=0.018) were significant predictors of survival in metastatic disease. CONCLUSIONS: These results confirm ER status as a primary prognostic factor in metastatic breast cancer. Furthermore, it also suggests that the presence of initial lymph node metastases could serve as a prognostic factor in recurrent breast cancer.