Academic Primary Care, Institute of Applied Health Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
Medical Statistics Team, Institute of Applied Health Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
Contraception. 2020 Sep;102(3):152-158. doi: 10.1016/j.contraception.2020.06.008. Epub 2020 Jun 25.
To examine the association between contemporary hormonal contraceptives and endometrial cancer risk in women younger than age 50.
Cohort study of women living in Denmark aged 15-49 years through 1995-2014. National registries provided information about hormonal contraception use, incident endometrial cancer and confounders. Ever, current or recent, and former users of any hormonal contraception were compared with non-users, using Poisson regression to calculate incidence rate ratios (RR) with 95% confidence intervals. Duration, time since last use, tumor-specific and product-specific analyses, and population prevented fraction, were calculated.
During 21.1 million person-years, 549 incident endometrial cancers occurred, with ever users of any hormonal contraception having a reduced premenopausal endometrial cancer risk compared with non-users; RR 0.60 (95% Confidence Interval 0.49 to 0.73). A lower risk of endometrial cancer was seen in all current or recent users of any hormonal contraception; 0.65 (0.52 to 0.83) and combined contraceptives; 0.57 (0.43 to 0.75), but not progestin-only contraceptives; levonorgestrel intrauterine system, LNG-IUS; 0.97 (0.66 to 1.42); other progestin-only contraceptives; 0.61 (0.27 to 1.37). Increased RRs were found for current use of any hormonal, combined contraceptives or LNG-IUS of ≤one year, probably because of protopathic bias. Longer durations of use were associated with significant reductions that became stronger with longer use. Former users of any hormonal contraception continued to benefit from a reduced risk of endometrial cancer >10 years after stopping. There was little evidence of differences in risk reduction by the type of progestin in combined oral contraceptives. Current or recent use of any hormonal contraception was associated with an approximate halving of risk of the most common tumor type I carcinoma, and an increased risk of the rarer sarcoma. Overall the estimated absolute reduced risk of endometrial cancer in ever users of hormonal contraceptives was 1.4 per 100,000 person-years, or approximately one less endometrial cancer for every 71,400 women of reproductive age who used hormonal contraception for one year. Use of hormonal contraception was estimated to prevent 25% of endometrial cancers in this population.
Currently available combined hormonal contraceptives are still associated with enduring protection against endometrial cancer, particularly for type I carcinomas.
We report substantive evidence of the association between different types of contemporary hormonal contraception and endometrial cancer risk in a national cohort of young Danish women. Currently available combined hormonal contraceptives are still associated with enduring protection against endometrial cancer, particularly for type I carcinomas.
研究 50 岁以下女性中当代激素避孕药与子宫内膜癌风险之间的关联。
对丹麦年龄在 15-49 岁的女性进行队列研究，截至 1995-2014 年。国家登记处提供了激素避孕药使用、新发子宫内膜癌和混杂因素的信息。比较了任何激素避孕药的既往、当前或近期使用者与非使用者，使用泊松回归计算 95%置信区间的发病率比（RR）。计算了持续时间、末次使用时间、肿瘤特异性和产品特异性分析以及人群预防分数。
在 2110 万个人年中，发生了 549 例新发子宫内膜癌，与非使用者相比，任何激素避孕药的既往使用者有降低的绝经前子宫内膜癌风险；RR0.60（95%置信区间 0.49-0.73）。所有当前或近期使用任何激素避孕药的患者的子宫内膜癌风险均降低；0.65（0.52-0.83）和联合避孕药；0.57（0.43-0.75），但孕激素仅避孕药；左炔诺孕酮宫内节育系统，LNG-IUS；0.97（0.66-1.42）；其他孕激素仅避孕药；0.61（0.27-1.37）。当前使用任何激素避孕药、联合避孕药或 LNG-IUS≤1 年的 RR 较高，可能是由于前病偏倚。使用时间较长与显著降低相关，使用时间越长，降低幅度越大。任何激素避孕药的既往使用者在停药 10 年后仍继续受益于降低子宫内膜癌风险。孕激素在联合口服避孕药中的类型对降低风险的差异几乎没有证据。当前或近期使用任何激素避孕药与最常见的 I 型癌的风险降低约一半相关，并且肉瘤的风险增加。总体而言，激素避孕药使用者中子宫内膜癌的绝对风险降低估计为每 100000 人年 1.4 例，即每 71400 名处于生育年龄的女性中，每 1 年使用激素避孕药，就可减少 1 例子宫内膜癌。据估计，该人群中激素避孕药的使用可预防 25%的子宫内膜癌。
目前可用的联合激素避孕药仍然与子宫内膜癌的持续保护相关，特别是对于 I 型癌。
我们报告了大量证据，证明不同类型的当代激素避孕药与丹麦年轻女性的子宫内膜癌风险之间存在关联。目前可用的联合激素避孕药仍然与子宫内膜癌的持续保护相关，特别是对于 I 型癌。
