Intra‐uterine contraception and the risk of endometrial cancer

Abstract

Despite the increasing world-wide popularity of contraceptive intra-uterine devices (IUDs), their potential long-term effects on the risk of developing endometrial carcinoma have been poorly studied. This paper reports on the relationship between intra-uterine contraception and endometrial cancer by analyzing epidemiological data from a large, multicenter, population-based, case-control study of epithelial endometrial cancer. Cases were 437 women, 20 to 54 years of age, with histologically confirmed epithelial endometrial cancer ascertained through 6 population-based cancer registries in the United States. Controls were 3200 women selected at random from the populations of these areas. The age- and parity-adjusted odds ratio (OR) for the association between ever having used intra-uterine contraception and endometrial cancer was 0.51 (95% confidence interval (CI) 0.3-0.8). Although the protective effect increased with duration of use, a dose-response relationship among users was not statistically demonstrable. The association did not vary significantly with age at first or last IUD use or with time elapsed since first or last IUD use. Years of education significantly modified the effect of intra-uterine contraception. Thus, intra-uterine contraception appeared to be strongly protective for women with at least 13 years of education (OR = 0.29, 95% CI, 0.15-0.6). It is proposed that intra-uterine contraception exerts its protective effect through local structural and biochemical changes in the endometrium that may alter endometrial sensitivity and response to circulating estrogen and progesterone.

Intrauterine Devices and Endometrial Cancer Risk: A Pooled Analysis of the Epidemiology of Endometrial Cancer Consortium

“…However, our pooled-OR of 0.81 is a more modest estimate of the association compared with previous studies, which reported ORs between 0.37 and 0.61 15,[19][20][21][22][23] . Three previous studies examined specific types of IUDs [17][18][19] , none of which demonstrated significant associations with any particular device, probably due to small numbers of cases and controls exposed to specific IUD types.…”

“…In 2007 and 2008, two meta-analyses examined the relationship between IUD use and endometrial cancer (EC) risk 1,13 . These analyses summarized ten epidemiologic studies [14][15][16][17][18][19][20][21][22][23] which together included 4,243 EC cases and 269,428 controls. These two meta-analyses reported odds ratios (ORs) of 0.54 1 [95% confidence interval (CI)=0.47-0.63] and 0.60 13 (95% CI=0.40-0.70) associated with ever use of IUDs.…”

Hormonal contraception and risk of endometrial cancer: a systematic review

“…It can be expected that LNG-IUS used for contraception protects primarily from endometrial cancer as do nonhormonal IUDs, although the mechanism differs between these IUSs (Aikat & Chadda 1980, Nilsson et al 1982, Johannisson 1987, Castellsague et al 1993, Raudaskoski et al 1998, Phillips et al 2003, Vereide et al 2005. Regarding the possible mechanisms of protection, there are important differences between nonhormonal IUDs and the (until now only available) hormonal LNG-IUS: although local intrauterine changes are suggested to be the main effect for contraception with both systems within a few days after insertion, only local endometrial effects without relevant systemic side effects (e.g.…”

Oral contraceptive and IUD use and endometrial cancer: A population‐based case–control study in Shanghai, China

“…12 Few epidemiological studies have examined the relationship between IUD use and endometrial cancer risk. 11,[14][15][16][17][18][19] A small-scale study we conducted in China in 1993 found no significant association. 11 In this report, we describe the association of OC and IUD use with endometrial cancer in a recently completed population-based case-control study conducted in Shanghai, China.…”