Association of Regimens of Hormone Replacement Therapy to Prognostic Factors among Women Diagnosed with Breast Cancer Aged 50–64 Years

Association of Regimens of Hormone Replacement Therapy to Prognostic Factors among Women Diagnosed with Breast Cancer Aged 50–64 Years

¹Fred Hutchinson Cancer Research Center, Division of Public Health Sciences, Seattle, Washington;
²University of Washington, School of Public Health and Community Medicine, Department of Epidemiology, Seattle, Washington;
³Department of Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California;
⁴Cancer Division, Centers for Disease Control and Prevention, Atlanta, Georgia;
⁵Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia;
⁶Center for Clinical Epidemiology and Biostatistics and Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania;
⁷Division of Epidemiology, Karmanos Cancer Institute at Wayne State University, Detroit, Michigan;
⁸Bay State Medical Center, Department of Obstetrics and Gynecology, Springfield, Massachusetts;
⁹Division of Hematology and Oncology, Karmanos Cancer Institute at Wayne State University, Detroit, Michigan; and
¹⁰Contraception and Reproductive Health Branch, Center for Population Research, National Institute of Child Health and Human Development, Bethesda, Maryland

Abstract

This study was conducted to assess the histopathological features of breast cancers in women diagnosed with breast cancer at 50–64 years of age who have and have not used hormone replacement therapy (HRT). A case-case analysis of the tumors from women aged 50–64 years who participated in a multicenter population-based case-control study of invasive breast cancer was conducted. In-person interviews collected a detailed history of all episodes of hormone use. Information was collected on selected tumor characteristics from 2346 women with breast cancer. Polytomous logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs), contrasting the histopathological characteristics of the tumors of women who used various regimens of HRT with those of women who have never used HRT. The tumors of cases who used each regimen of HRT were smaller and of earlier stage than those of non-HRT users. Adjustment for screening diminished the magnitude of the effect, and only cases who used estrogen alone (estrogen replacement therapy) had reduced odds of being diagnosed with later-stage disease (regional or distant) than cases who never used HRT (OR, 0.7; 95% CI, 0.6–0.9). Higher proportions of estrogen receptor (ER)- and progesterone receptor (PR)-positive tumors were seen in cases who used any regimen of HRT versus those who did not use HRT. However, after adjustment for age and race, only the tumors of cases who used continuous combined HRT remained more likely to be ER+ and PR+ [OR ER− = 0.6 (95% CI, 0.4–0.9) and OR PR− = 0.5 (95% CI, 0.4–0.7)]. The tumors of women with breast cancer who used HRT have some better prognostic factors than those of women who have not used HRT. However, with the exception of the results noted above, this advantage may be due to the racial and age differences in those who use the various regimens of HRT and the effect of more frequent screening among HRT users, leading to earlier diagnosis.

Footnotes

Grant support: This study was supported by the National Institute of Child Health and Human Development, with additional support from the National Cancer Institute, through contracts with Emory University (N01 HD 3-3168), Fred Hutchinson Cancer Research Center (N01 HD 2-3166), Karmanos Cancer Institute at Wayne State University (N01 HD 3-3174), University of Pennsylvania (N01 HD-3-3176), and University of Southern California (N01 HD 3-3175), and through an intra-agency agreement with the Centers for Disease Control and Prevention (Y01 HD 7022). It was also supported by Surveillance, Epidemiology, and End Results Programs N01 CN 0532, N01 CN 65064, N01 PC 67010, and N01 PC 67006.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Present address: Linda K. Weiss, National Cancer Institute, Bethesda, Maryland 20892.
Requests for reprints: Janet R. Daling, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North (MP 381), P. O. Box 19024, Seattle, Washington 98109-1024. Phone: (206) 667-4630; Fax: (206) 667-5948; E-mail: jdaling{at}fhcrc.org
↵11 The abbreviations used are: HRT, hormone replacement therapy; OR, odds ratio; CI, confidence interval; ERT, estrogen replacement therapy; ER, estrogen receptor; PR, progesterone receptor; CHRT, combined HRT; C-CHRT, continuous CHRT; S-CHRT, sequential CHRT; CARE, Contraceptive and Reproductive Experience; ICD-O, International Classification of Diseases for Oncology.
- Accepted July 17, 1903.
- Received March 28, 1903.
- Revision received June 30, 1903.