This study aims to summarize evidence from observational studies about the lifetime use of HC and the risk of BC in women of reproductive age. The PubMed, Cochrane, and EMBASE databases were searched for observational studies published from 2015 to February 2022. Meta-analyses were performed using adjusted odds ratios and relative risks with a random-effects model using the I2statistic to quantify the heterogeneity among studies. Of the 724 studies identified, 650 were screened for title/abstract selection, 60 were selected for full-text revision, and 22 were included in the meta-analysis. Of these, 19 were case-control studies and 3 were cohort studies. The results of the meta-analysis indicate a significantly higher risk of developing BC in ever users of HC (pooled OR = 1.33; 95% CI = 1.19 to 1.49). This effect is larger in the subgroups of case-control studies (pooled OR = 1.44, 95% CI = 1.21 to 1.70) and in the subgroup of studies that strictly define menopausal status (pooled OR = 1.48; 95% CI, 1.10 to 2.00). Although our meta-analysis of observational studies (cohort and case-control) suggests a significantly increased overall risk of BC in users or ever-users of modern hormonal contraceptives, the high heterogeneity among studies (>70%) related to differences in study design, measurement of variables, confounders, among other factors, as well as publication biases should be considered when interpreting our results.
本研究旨在总结观察性研究中关于育龄女性使用激素避孕药（HC）与乳腺癌（BC）风险关联的证据。通过检索PubMed、Cochrane和EMBASE数据库，纳入2015年至2022年2月发表的观察性研究。采用随机效应模型对调整后的比值比和相对风险进行荟萃分析，并通过I²统计量量化研究间异质性。在初步检索到的724项研究中，650项进入标题/摘要筛选，60项进入全文复审，最终22项纳入荟萃分析，其中19项为病例对照研究，3项为队列研究。荟萃分析结果显示，曾使用HC者患乳腺癌风险显著升高（合并OR=1.33；95% CI=1.19-1.49）。在病例对照研究亚组（合并OR=1.44，95% CI=1.21-1.70）及严格界定绝经状态的研究亚组（合并OR=1.48；95% CI=1.10-2.00）中，该效应更为显著。尽管本观察性研究（队列与病例对照）荟萃分析提示现代激素避孕药使用者或曾使用者总体乳腺癌风险显著增加，但在解读结果时需注意研究间存在高度异质性（>70%），这可能源于研究设计、变量测量、混杂因素控制等方面的差异，同时发表偏倚亦需纳入考量。
Hormonal Contraception and the Risk of Breast Cancer in Women of Reproductive Age: A Meta-Analysis
肿瘤(癌症)患者之家