Tumor size, axillary lymph node status and steroid receptor expression in breast cancer:: prognostic relevance 5 years after surgery

Tumor size, axillary lymph node status and expression of steroid receptors are well-established prognostic factors in breast cancer. However, it is not clear if these prognostic factors are time-dependent variables and lose their significance after several years of disease-free survival. To analyse how long these factors keep their prognostic relevance survival of 1162 breast cancer patients was analysed retrospectively. The post-operative follow-up period was split into consecutive 2-year intervals and each interval was analysed for rate of recurrence and rate of tumor depending deaths. Furthermore, a multivariate analysis was performed for the total follow-up time and for the follow-up period starting 5 years after surgery. Multivariate analysis revealed tumor size, axillary lymph node status and estrogen receptor status as independent prognostic parameters. Analysing separately the rate of recurrences and tumor-related deaths during consecutive 2-year intervals, only the tumor size was a constant prognostic parameter, whereas prognostic relevance of lymph node status decreased. Estrogen receptor status associated with favourable prognosis during the first years after surgery changed to an unfavourable prognostic factor 4 years after surgery. To summarize, prognostic factors obtained at the time of surgery can lose their significance with increasing disease-free survival.