Prognostic factors observed in current clinical trials

Adjuvant therapy of breast cancer has evolved over the past 15 years from an interesting clinical experiment to the standard of care for many patients. The toxicities of different treatments vary from those with minimal side effects, such as tamoxifen, to those with potentially life-threatening side effects. Current clinical trials are evaluating increasingly higher risk treatments, such as high-dose chemotherapy autologous bone marrow rescue. Chemotherapy is being used in groups that have previously been treated only with hormonal interventions or who have received no adjuvant therapy. The delineation of risk, such that the risks of treatment can be closely tied to the risk of recurrence is thus a desirable goal for clinical-laboratory research. Prognostic factors identified in treated patients, however, may be measures of treatment resistance versus treatment sensitivity rather than some underlying biologic characteristic defining a tumor's malignant potential.