BACKGROUND: The presence of sex steroid receptors in breast cancer tissue is of considerable diagnostic/prognostic value. However, the relative utility of the diverse assays used for receptor detection/quantitation is disputed. We compared the utility of a monoclonal antibody-based semiquantitative immunohistochemical assay of estrogen receptor alpha (irERalpha) and of quantitative single-point radioligand assays of "cytosolic" estrogen (ERc) and progesterone receptors (PRc). MATERIAL/ METHODS: Correlations were studied between the receptor levels in 235 breast cancers in patients treated between 1987 and 1990. Relationships were then analyzed between tumor receptor status, overall survival (OS; end-point: 10 years postmastectomy), age, axillary nodal status, and adjuvant tamoxifen in primary breast cancer patients for whom the respective data were accessible (N < or =121). RESULTS: Univariate analysis showed no correlation between OS and the ERc status, whereas positive irERalpha status was a favorable (p<0.05) prognosticator for the 5-year follow-up, and positive PRc status for the 10-year follow-up. Lymph node-positive patients who received adjuvant tamoxifen (2 x 10 mg/day) for a minimum of 12 months had significantly longer OS than those who did not receive the treatment. Multivariate regression of Cox proportional risk showed significance of axillary metastases, adjuvant tamoxifen, and ER status, but not of age and PRc status as independent prognosticators of OS. CONCLUSIONS: These results show the prognostic utility of the PRc radioligand assay, a slight prognostic advantage of the irERalpha assay over the radioligand ERc assay, and stress the importance of adjuvant antiestrogen therapy for overall survival in node-positive primary breast cancer patients.
BACKGROUND: The presence of sex steroid receptors in breast cancer tissue is of considerable diagnostic/prognostic value. However, the relative utility of the diverse assays used for receptor detection/quantitation is disputed. We compared the utility of a monoclonal antibody-based semiquantitative immunohistochemical assay of estrogen receptor alpha (irERalpha) and of quantitative single-point radioligand assays of "cytosolic" estrogen (ERc) and progesterone receptors (PRc). MATERIAL/ METHODS: Correlations were studied between the receptor levels in 235 breast cancers in patients treated between 1987 and 1990. Relationships were then analyzed between tumor receptor status, overall survival (OS; end-point: 10 years postmastectomy), age, axillary nodal status, and adjuvant tamoxifen in primary breast cancerpatients for whom the respective data were accessible (N < or =121). RESULTS: Univariate analysis showed no correlation between OS and the ERc status, whereas positive irERalpha status was a favorable (p<0.05) prognosticator for the 5-year follow-up, and positive PRc status for the 10-year follow-up. Lymph node-positive patients who received adjuvant tamoxifen (2 x 10 mg/day) for a minimum of 12 months had significantly longer OS than those who did not receive the treatment. Multivariate regression of Cox proportional risk showed significance of axillary metastases, adjuvant tamoxifen, and ER status, but not of age and PRc status as independent prognosticators of OS. CONCLUSIONS: These results show the prognostic utility of the PRc radioligand assay, a slight prognostic advantage of the irERalpha assay over the radioligand ERc assay, and stress the importance of adjuvant antiestrogen therapy for overall survival in node-positive primary breast cancerpatients.