Adjuvant anthracycline therapy as a prognostic factor in metastatic breastcancer

Background. Prognostic factors in metastatic breast cancer continue to be i dentified. Previous adjuvant chemotherapy appeared to have poor prognosis i n some studies but, despite this, the prior use of anthracyclines in the ad juvant setting has not been clearly established as an adverse prognostic fa ctor once metastatic disease develops. Patients and methods. Patients (n = 1,436) with stages I-IIIa breast cancer were surgically treated with/without radiotherapy and/or systemic adjuvant treatment. Of these, 297 patients who relapsed with metastatic disease con stitute the sample population of this retrospective study. Survival, as a f unction of time since diagnosis of metastatic disease, was assessed in rela tion to the following factors: age, size of the primary tumor, grade, numbe r of positive axillary nodes, type of surgery, type of adjuvant treatment a dministered, time to relapse, number of metastatic sites, presence of visce ral metastases and type of treatment employed at the time of relapse. Results. In multivariable analysis three factors remained significant predi ctors of short survival time: more than 1 site of metastases (p = 0.00003), shorter time to relapse (p = 0.003) and the previous administration of ant hracyclines as adjuvant therapy (p = 0.005). Conclusions. The prior use of adjuvant anthracyclines, with other known cli nical prognostic factors, confers a poorer outcome in metastatic disease, p erhaps as a result of resistant clones selection or by induction of de novo resistance.