Examples of the association of serum estrogens and HRTs with increasing risk of breast cancer in postmenopause
| Serum Estrogen Levels (Postmenopausal), HRT, and Breast Cancer Risk | |||
|---|---|---|---|
| Study | Healthy Controls | Breast Cancer | Significance |
| Berrino et al., 1996 (HC = 88; BC = 24)1-a | 0.08 nM | 0.09 nM | p = 0.027 |
| Zeleniuch-Jacquotte et al., 1995 ER+ (HC = 101; BC = 53) | 0.107 nM | 0.133 nM | p = 0.05 |
| ER− (HC = 45; BC = 23) | 0.086 nM | 0.110 nM | p = 0.07 |
| ER unknown (HC = 102; BC = 54) | 0.099 nM | 0.121 nM | p = 0.04 |
| Overall mean estimates | 0.093 nM | 0.114 nM | |
| Study | Free Serum Estradiol1-b | OR (Unadjusted) | OR (Adjusted) |
|---|---|---|---|
| Toniolo et al. (1995) | <1 pM | 1.0 | 1.0 |
| 1–1.7 pM | 1.5 (0.8, 3.0) | 1.4 (0.7, 2.8) | |
| 1.7–2.4 pM | 3.8 (1.95, 7.5) | 3.0 (1.4, 6.3) | |
| >2.4 pM | 3.9 (1.8, 8.1) | 2.9 (1.3, 6.6) |
| HRT—Estrogens Alone1-c | |
|---|---|
| Study | Risk Estimates |
| CGHFBC (1997) 1-d | RR = 1.14 ± 0.03 (p = 0.00001) |
| Schairer et al., 2000 1-e | RR = 1.1 (1.0, 1.3) |
| Magnusson et al., 1999 1-f | OR = 1.99 (1.67, 2.38) |
| Serum Estrogen Levels in Premenopausal Women1-g | |
|---|---|
| Follicular phase | ≤0.28 nM |
| Luteal phase | ≤1.1 nM |
| Pregnancy: 3rd trimester | ≤150 nM |
↵1-a HC = health control; BC = breast cancer patients. There were a total of 4,043 women enrolled in the Berrino et al. study and 7,063 women in the Zeleniuch-Jacquotte study.
↵1-b Quartiles (approximate) of serum estradiol concentrations and odds ratios for postmenopausal breast cancer. Data are adjusted for the Quetelet index (Toniolo et al., 1995).
↵1-c There are various differences in study design, population, and analysis. Nonetheless, these selected studies reflect the generally consistent association of increased breast cancer risk with estrogenic HRT use. Data are presented as provided in each publication. RR = relative risk; OR = odds ratio.
↵1-d CGHFBC = Collaborative Group on Hormonal Factors in Breast Cancer. Data for every use presented as relative risk ± S.E.
↵1-e Data for every use presented as relative risk and 95% confidence interval.
↵1-f Data for every use of medium-potency estrogens presented as odds ratio and 95% confidence interval.
↵1-g Estimated upper limits in normal women. These values are provided as a general reference, with there being considerable variability among women. The highest concentrations of estrogens are found during the third trimester of pregnancy.