The changing importance of prognostic factors in breast cancer during long-term follow-up.

A cohort of 464 breast-cancer patients were followed up for over 10 years and the clinical, histological and morphometric factors were related to survival within different time periods during follow-up. Tumor diameter, axillary lymph-node status (pN), tubule formation and the fraction of intraductal growth as determined from the primary tumor biopsy specimen had prognostic value up to 5 years. Histological grade, morphometric nuclear factors and the M/V index had only short-term prognostic value immediately after the primary therapy. In axillary lymph-node-negative (ANN) tumors tubule formation, intraductal growth, tumor necrosis and tumor diameter had prognostic value during the first 3 postoperative years. In axillary lymph-node-positive (ANP) tumors, tumor diameter, intraductal growth and tubule formation had long-term prognostic value whereas the M/V index had prognostic value only for 1 postoperative year. Tumor diameter, axillary lymph-node status, tubule formation and the proportion of intraductal growth also had independent long-term prognostic value in a multivariate analysis and accordingly these factors can categorize breast-cancer patients into prognostic groups after several years of follow-up. In contrast, mitotic frequency loses its prognostic power within 2 postoperative years, while morphometric nuclear factors and histological grade have no practical prognostic value after 1 year of follow-up.