ESTROGEN-RECEPTOR NEGATIVE AND PROGESTERONE-RECEPTOR POSITIVE PRIMARYBREAST-CANCER - PATHOLOGICAL CHARACTERISTICS AND CLINICAL OUTCOME

The expression of estrogen (ER) and progesterone (PgR) receptors was a nalyzed in a retrospective series of 3000 patients who had operable pr imary breast cancer. Patients were stratified according to ER and PgR status and the study was focused on the two groups (ER-PgR+ and ER-PgR -) of patients whose tumors contained low levels of ER (< 15 fmol/mg p rotein), regarding potential response to endocrine therapy. The compar ison of clinical or histological characteristics between ER-PgR+ and E R-PgR- patients was analyzed as well as the disease-related death and survival, The mean follow-up was 86.3 months. Among the 529 ER-patient s. 62 were PgR+ (12%), whereas 467 were PgR- (88%). The ER-PgR+ and ER -PgR- populations represented 2% and 15.6% of the overall population, respectively. In ER- tumors, the PgR status was significantly related to: age, menopausal status, tumor size, SBR grade, and histological ty pe, but not to the type of surgical treatment or to lymph node involve ment. ER-PgR+ tumors had smaller size (64% T1 vs 43%) (p = 0.004) and were more frequently grade I (28% vs 12%) than ER-PgR- tumors (p < 0.0 01), In addition, the patients with ER-PgR+ tumors were significantly younger (49.4 years vs 58.4 years; p < 0.0001), and were more frequent ly premenopausal (76% vs 36%; p < 0.001). The disease-free interval an d the metastasis-free survival tended to be worse for ER-PgR- than for ER-PgR+ patients, but the difference was not statistically significan t at 10 years, However, a small but significant difference in overall survival, in favor of the PgR+ group, was observed between the two gro ups during the first 5 years (p = 0.03). We conclude that in combinati on with ER, PgR status defines a group of patients with clinical and b iological specificity, which could be considered for specific endocrin e therapy.