The effect of age on estrogen and progesterone receptor in primary breast cancer

Efficacy of First‐Line Letrozole Versus Tamoxifen as a Function of Age in Postmenopausal Women with Advanced Breast Cancer

PURPOSE

To compare the efficacy, in regard to time to progression (TTP) and objective response rate (ORR), of letrozole (Femara; Novartis Pharma AG; Basel Switzerland), an oral aromatase inhibitor, with that of tamoxifen (Tamofen; Leiras OY; Turku, Finland) as first-line therapy in younger (<70 years) and older (>/=70 years) postmenopausal women with advanced breast cancer.

MATERIALS AND METHODS

Nine hundred seven patients with advanced breast cancer were randomly assigned to receive 2.5 mg letrozole (n = 453) or 20 mg tamoxifen (n = 454) once daily in a double-blind, multicenter, international trial. Among the prospectively planned analyses were analyses of TTP and ORR by age (<70 and >/=70 years). The results of these prospectively planned analyses are reported here.

RESULTS

Letrozole was as effective in older postmenopausal women (>/=70 years of age) as it was in younger postmenopausal women (<70 years of age). The overall ORR in the older subgroup was significantly higher in patients treated with letrozole (38%) than in patients treated with tamoxifen (18%). In the younger subgroup of postmenopausal patients, the ORRs were not significantly different (letrozole, 26%; tamoxifen, 22%). TTP was significantly longer for letrozole than for tamoxifen in both age groups (younger: letrozole median TTP, 8.8 months; tamoxifen, 6.0 months; older: letrozole median TTP, 12.2 months; tamoxifen, 5.8 months). Although age was independently prognostic of TTP, there was no significant effect of age on ORR in the presence of other factors.

CONCLUSION

The data show that letrozole, 2.5 mg once daily, is as effective in older, postmenopausal women as it is in younger postmenopausal women with advanced breast cancer. In addition, letrozole was more effective than tamoxifen in both younger and older patients.

The 1999 James Ewing Lecture: in pursuit of molecules of oncogenesis and neoplastic therapy

Breast cancer is a progressive, phenotypic, genetic and epigenetic alteration, induced by various stimulants of which the principal steroid hormone, estrogen, initiates and promotes neoplastic transformation of normal ductal mammary epithelium to acquire distinct biochemical and molecular characteristics. The molecular events that characterize oncogenesis with dysregulated physiologic states represent an area of intense translational research. The progress of the last century suggests that the targeted responses initiated by this steroid hormone can be attenuated and modified with anti-estrogen therapies or through applied intervention with selective estrogen receptor modulation. New pharmacological, genetic, and biological agents will undoubtedly afford clinical investigators of the next millennium the opportunity to provide major impact on the disease progression of this neoplasm, through these targeted endocrine responses for estrogen.

Estrogen and progesterone receptor concentrations and prevalence of tumor hormonal phenotypes in older breast cancer patients

We examined the concentrations of estrogen (ER) and progesterone receptors (PR) and the distribution of tumor phenotypes as a function of age in breast cancer patients. ER and PR concentrations were determined in tissue biopsies from 1739 patients with primary breast cancer, using ligand binding assays. Tumors were classified as estrogen receptor positive (ER+) or negative (ER-) and progesterone receptor positive (PR+) or negative (PR-) based on the presence or absence of receptor binding activity. Tumors were stratified into four phenotypes: ER+PR+; ER+PR-; ER-PR+; and ER-PR-. Significant positive associations were found between ER concentration and age (p = 0.0001) and between PR concentration and age (p = 0.0002). The median ER concentrations were statistically different by age groups, with the greatest levels in older versus younger patients. The prevalence of ER+PR+ tumor phenotype increased with age. In contrast, the prevalence of ER-PR- and ER-PR+ tumor phenotypes decreased with age. The median PR-to-ER ratio decreased with age (p = 0.0001), and this trend was attributed to increased ER concentration with age. The prevalence of ER-PR- and ER-PR+ tumor phenotypes is greater in younger patients suggesting that hormonal regulation of ER gene expression may be responsible for the observed age disparity of tumor phenotypes in breast cancer.

Methodology of immunohistological detection of oestrogen receptor in human breast carcinoma in formalin-fixed, paraffin-embedded tissue: a comparison with frozen section methodology

We describe a method of immunohistochemically assessing estrogen receptor status on routinely processed formalin-fixed tissue, using a commercially available monoclonal antibody (Abbott H222), with pronase predigestion of tissue sections and overnight antibody incubation. The staining was assessed using the H score system. A series of 94 cases of breast cancer were analysed and the results were compared with assessment by oestrogen receptor immunocytochemical assay performed on frozen section. Direct comparison of the paired sets of H scores obtained with frozen tissue and formalin-fixed tissue showed a highly significant correlation of 0.8 (P < 0.001) between the two methods of oestrogen receptor assessment. Chi-squared analysis using H score cut off points of 50 and 100 also showed a similar significant association (P < 0.001). We conclude that this oestrogen receptor method, applicable to formalin-fixed, paraffin-embedded tissue, gives accurate results on routinely fixed tissue and could be used as an alternative to other methods.

The effect of tumor size and axillary lymph node metastasis on estrogen and progesterone receptors in primary breast cancer

We evaluated the estrogen receptors (Er) and the progesterone receptors (Pr) in 209 female patients with primary breast cancer. There is statistically a very highly significant negative correlation between the size of the tumor and the Pr (p = 0.007); large tumor contains low Pr. The same correlation was found with Er, but it was not statistically significant (p = 0.40). There is also a negative correlation between the number of axillary metastatic lymph nodes and Er and Pr, but this was not statistically significant.