Dupont W D, Page D L
Department of Preventive Medicine, Vanderbilt University School of Medicine, Nashville, Tenn. 37232-2637.
Arch Intern Med. 1991 Jan;151(1):67-72.
We conducted a meta-analysis of the literature concerning breast cancer and estrogen replacement therapy. The overall relative risk of breast cancer associated with this therapy was 1.07. However, the variation of the estimated risks among the studies was far greater than could plausibly be explained by chance alone. To explain this variation, we looked at the effects of type, duration, and dosage of treatment. Overall, women who took 0.625 mg/d or less of conjugated estrogens had a risk of breast cancer that was 1.08 times that of women who did not receive this therapy (95% confidence interval [CI], 0.96 to 1.2). The relative risks from these individual studies of low-dosage therapy did not differ significantly from each other. Women who took 1.25 mg/d or more of conjugated estrogens had a breast cancer relative risk of 2.0 or less in all studies. However, the variation in observed risks at this higher dosage was significant. This implies that other risk factors varied among these studies, making it difficult to estimate the overall risk associated with this dosage. The relative risk of breast cancer associated with estrogen replacement therapy among women with a history of benign breast disease was 1.16 (95% CI, 0.89 to 1.5). The combined results from multiple studies provide strong evidence that menopausal therapy consisting of 0.625 mg/d or less of conjugated estrogens does not increase breast cancer risk.
我们对有关乳腺癌与雌激素替代疗法的文献进行了荟萃分析。与该疗法相关的乳腺癌总体相对风险为1.07。然而，各研究中估计风险的差异远大于仅由偶然因素所能合理说明的范围。为了解释这种差异，我们研究了治疗类型、持续时间和剂量的影响。总体而言，每日服用0.625毫克或更少结合雌激素的女性患乳腺癌的风险是未接受该疗法女性的1.08倍（95%置信区间[CI]，0.96至1.2）。这些低剂量疗法的个体研究得出的相对风险彼此之间无显著差异。在所有研究中，每日服用1.25毫克或更多结合雌激素的女性乳腺癌相对风险为2.0或更低。然而，在此较高剂量下观察到的风险差异显著。这意味着这些研究中的其他风险因素各不相同，因此难以估计与该剂量相关的总体风险。有良性乳腺疾病史的女性中，雌激素替代疗法相关的乳腺癌相对风险为1.16（95%CI，0.89至1.5）。多项研究的综合结果提供了有力证据，表明每日服用0.625毫克或更少结合雌激素的绝经疗法不会增加乳腺癌风险。
