Steinberg K K, Thacker S B, Smith S J, Stroup D F, Zack M M, Flanders W D, Berkelman R L
Center for Environmental Health and Injury Control, Centers for Disease Control, Atlanta, GA 30333.
JAMA. 1991 Apr 17;265(15):1985-90.
To quantify the effect of estrogen replacement therapy on breast cancer risk, we combined dose-response slopes of the relative risk of breast cancer against the duration of estrogen use across 16 studies. Using this summary dose-response slope, we calculated the proportional increase in risk of breast cancer for each year of estrogen use. For women who experienced any type of menopause, risk did not appear to increase until after at least 5 years of estrogen use. After 15 years of estrogen use, we found a 30% increase in the risk of breast cancer (relative risk, 1.3; 95% confidence interval [CI], 1.2 to 1.6). The increase in risk was largely due to results of studies that included premenopausal women or women using estradiol (with or without progestin), studies for which the estimated relative risk was 2.2 (CI, 1.4 to 3.4) after 15 years. Among women with a family history of breast cancer, those who had ever used estrogen replacement had a significantly higher risk (3.4; CI, 2.0 to 6.0) than those who had not (1.5; CI, 1.2 to 1.7).
为了量化雌激素替代疗法对乳腺癌风险的影响，我们汇总了16项研究中乳腺癌相对风险相对于雌激素使用时长的剂量反应斜率。利用这个汇总的剂量反应斜率，我们计算了每年使用雌激素时乳腺癌风险的比例增加情况。对于经历任何类型更年期的女性，风险似乎在使用雌激素至少5年后才会增加。使用雌激素15年后，我们发现乳腺癌风险增加了30%（相对风险为1.3；95%置信区间[CI]为1.2至1.6）。风险增加在很大程度上归因于纳入了绝经前女性或使用雌二醇（无论是否联合孕激素）的女性的研究结果，对于这些研究，15年后估计的相对风险为2.2（CI为1.4至3.4）。在有乳腺癌家族史的女性中，曾经使用过雌激素替代疗法的女性的风险（3.4；CI为2.0至6.0）显著高于未使用过的女性（1.5；CI为1.2至1.7）。
