Prediction of clinical outcome from primary tamosifen by expression of biologic markers in breast cancer patients

The aim of this study was to evaluate pretreatment clinical features and bi ological markers together with changes in these factors as predictors of re sponse and relapse in patients receiving tamoxifen for primary breast cance r. Fine-needle aspiration cytology of the primary breast canter was perform ed before tamoxifen treatment in 54 patients and repeated after therapy on day 14, day 60, or on both days in a subset of 35 patients. These samples w ere evaluated for estrogen receptor (ER), progesterone receptor (PgR), Ki67 , S-phase fraction and ploidy. The overall response to tamoxifen was 57% (3 1 of 53 patients). Pretreatment ER and PgR significantly predicted for resp onse by univariate analysis (P < 0.0001 and P < 0.003, respectively). By mu ltivariate analysis, ER expression Ras the only independent predictor of re sponse, and it was associated with 27 times the likelihood of response (95% confidence interval, 6-136), Increase in PgR and decrease in Ki67 on day 1 4 significantly predicted for response to tamoxifen (P < 0.03 and P < 0.04, respectively), Lack of ER, clinical node-positive disease, and failure to decrease Ki67 on day 14 were significantly associated with increased risk o f relapse (P < 0.05), By multivariate analysis, ER expression was the only independent predictor of relapse (P < 0.005), Pretreatment and early change s in molecular marker expression may assist in the prediction of response a nd clinical outcome in primary breast cancer patients receiving tamoxifen.