Intrauterine systems and gynaecological malignancies: an umbrella review of systematic reviews and meta-analyses.

Background: The intrauterine system (IUS) is globally recognised as a reliable, safe, and cost-effective form of contraception.

Aim: This umbrella review of systematic reviews and meta-analyses aims to synthesise current evidence regarding the association between IUS usage and the risk of gynaecological malignancies, specifically ovarian, endometrial, cervical, and breast cancer.

Method: A comprehensive search of PubMed/MEDLINE, Cochrane Library, and Ovid databases was conducted up to July 2024 for systematic reviews and meta-analyses examining any type of IUS in relation to gynaecological cancers. The screening and data extraction processes adhered to PRISMA guidelines and random-effects meta-analysis was employed for data synthesis.

Results: A total of 323 titles and abstracts were screened, leading to the review of 40 full texts and the inclusion of 21 systematic reviews and meta-analyses. In the preliminary analysis, 10 individual studies reported on ovarian cancer, 9 on endometrial cancer, and 8 on cervical cancer, all indicating a decreased odds ratio for cancer associated with ever-use of the IUS (0.68 [95% CI = 0.56 to 0.83], 0.41 [95% CI = 0.31 to 0.54], and 0.60 [95% CI = 0.46 to 0.79], respectively; all P<0.001). Additionally, two studies on breast cancer showed a non-statistically significant increased odds ratio (1.21 [95% CI = 0.90 to 1.61], P = 0.21).

Conclusion: Ever-use of intrauterine contraception is associated with a reduced risk of ovarian, endometrial, and cervical cancers, while suggesting a potential increase in breast cancer risk. These findings can inform patient counselling to better balance the benefits and risks of IUS use.