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Epidemiologic studies fairly consistently show in postmenopausal women that reproductive steroid hormones contribute to primary breast cancer risk, and this association is strongly supported by experimental studies using laboratory animals and model systems.
Evidence linking sex hormone concentrations with risk for recurrence in women diagnosed with breast cancer is limited; however, beneficial effects of antiestrogenic therapy on recurrence-free survival suggest that these hormones affect progression and risk for recurrence.
This study examined whether baseline serum concentrations of estradiol, testosterone, and sex hormone binding globulin were associated with recurrence-free survival in a nested case-control cohort of women from a randomized diet trial (Women's Healthy Eating and Living Study) who were followed for >7 years after diagnosis.
In 153 case-control pairs of perimenopausal and postmenopausal women in this analysis:
Total estradiol [hazard ratio (HR), 1.41 per unit increase in log concentration; 95% confidence interval (95% CI), 1.01-1.97], bioavailable estradiol (HR, 1.26; 95% CI, 1.03-1.53), and free estradiol (HR, 1.31; 95% CI, 1.03-1.65) concentrations were significantly associated with risk for recurrence.
Recurred women had an average total estradiol concentration that was double that of nonrecurred women (22.7 versus 10.8 pg/mL; P = 0.05).
Testosterone and sex hormone binding globulin concentrations did not differ between cases and controls and were not associated with risk for recurrence.
Although genetic and metabolic factors likely modulate the relationship between circulating sex hormones and risk, results from this study provide evidence that higher serum estrogen concentration contributes to risk for recurrence in women diagnosed with early stage breast cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(3):OF1–7).
Source: Cancer Epidemiology, Biomarkers & Prevention. March 6, 2008. [E-pub ahead of print.] DOI: 10.1158/1055-9965.EPI-07-0761 by Rock CL, Flatt SW, Laughlin GA, Gold EB, Thomson CA, Natarajan L, Jones LA , Caan BJ, Stefanick ML, Hajek RA, Al-Delaimy WK, Stanczyk FZ, Pierce JP, for the Women's Healthy Eating and Living Study Group. Moores UCSD Cancer Center, University of California-San Diego, La Jolla, California; Department of Public Health Sciences, University of California-Davis, Davis, California; Arizona Cancer Center, University of Arizona, Tucson, Arizona; University of Texas M. D. Anderson Cancer Center, Houston, Texas; Division of Research, Kaiser Permanente Northern California, Oakland, California; Stanford Comprehensive Cancer Center, Stanford University, Stanford, California; and Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, California. [E-mail: email@example.com]