Prognostic factors and the curability of breast cancer.

Over the years three different concepts regarding the cure of treated breast cancer have emerged. These are clinical cure, personal cure and statistical cure. The latter is the most accurate estimate of the curability of a disease which is presumed to be fatal unless treated. Statistical cure is the elimination of the hazard of death in a treated group compared with an age-matched control population. When statistical cure is studied in patients treated for early breast cancer, it is clear that breast cancer is an incurable disease. The expected gains from the relatively recent introduction of adjuvant therapy are too small to alter this concept. The significance of prognostic factors in a disease deemed to be incurable therefore requires re-examination. The conventional prognostic factors of tumour size, nodal status and a combination of those two in staging systems significantly discriminates in terms of survival in the short term. However, when the characteristics of long-term survivors are examined, neither tumour size nor nodal status discriminates effectively. If this is the case, then we need to reconsider novel treatment strategies which have been introduced in the hope of increasing the curability of the disease and the selection for those treatment strategies of patients using the conventional prognostic factors of tumour size or nodal involvement.