SHORT RECURRENCE-FREE SURVIVAL ASSOCIATED WITH HIGH ESTROGEN-RECEPTORLEVELS IN THE NATURAL-HISTORY OF POSTMENOPAUSAL, PRIMARY BREAST-CANCER

The ability of oestrogen and progesterone receptor (ER and PgR, respec tively) status to discriminate recurrence-free survival (RFS) among a cohort of consecutively accrued 952 postmenopausal patients has been s tudied. None of the cohort members investigated were treated with adju vant therapy. Using a graduated scale of receptor status [low, interme diate and high receptor levels (< 10 vs. 10-107 vs. greater-than-or-eq ual-to 108 fmol/mg cytosol protein, respectively)] instead of the more commonly used dichotomous subdivision (positive vs. negative), ER lev el significantly discriminated between groups of patients with long vs . short RFS. Contrary to our expectations, patients with highest ER le vels have as poor a prognosis as ER-negative patients, while patients with intermediate ER levels have longest RFS. The group of patients wi th ER levels greater-than-or-equal-to 108 fmol/mg cytosol protein comp rises 47% of the cohort. The independent significance of overexpressio n of ER as a prognostic factor among this patient group is demonstrate d in multivariate analysis where ER level is more significant than eit her grade of anaplasia or tumour size. PgR status did not significantl y predict RFS among these patients. While the highest ER levels predis pose for poorer prognosis among postmenopausal patients, it is precise ly this group that experiences greatest benefit from adjuvant treatmen t with tamoxifen. Thus, patients who might otherwise go untreated due to their node-negative status can be readily identified and offered ad juvant treatment.