Association of female genital schistosomiasis and human papillomavirus and cervical pre-cancer: a systematic review.

Background: S. haematobium is a recognized carcinogen and is associated with squamous cell carcinoma of the bladder. Its association with high-risk(HR) human papillomavirus (HPV) persistence, cervical pre-cancer and cervical cancer incidence has not been fully explored.

Methods: We searched OvidSP MEDLINE, OvidSP Embase, Global Index Medicus, PubMed and the Wiley Cochrane library without date or language restrictions up to April 20, 2024 for abstracts evaluating the association of female genital schistosomiasis (FGS) with the prevalence, incidence or persistence of cervical HR-HPV, and incidence of histology-verified cervical pre-cancer or cancer. Cervical pre-cancer defined using cervical cytology or visual inspection with acetic acid (VIA) was also considered, but as lower quality evidence. We assessed the risk of bias of included studies using a modified Newcastle Ottawa scale. This study is registered on PROSPERO: CRD42023389301.

Results: We identified 1,170 publications and six studies were eligible for inclusion. Five studies were cross sectional and 1 was prospective. The studies describe 1081 women living in sub-Saharan Africa. One study from Zimbabwe reported an increased risk of HR-HPV prevalence at baseline in women with composite-FGS compared to women without FGS (aOR 1.9, 95% CI 1.1 - 3.6, p = 0.03), however no association was seen after 5 years of follow-up. Another study from KwaZulu-Natal reported an increased odds of any HPV prevalence among women with visual-FGS compared to women without FGS (aOR 1.71 [1.14 - 2.56], p = 0.01). However, a study in Madagascar did not show increased odds of any HPV among women with visual-FGS compared to women without FGS (OR 1.0 [0.82 - 1.2). Of 4 studies evaluating the association of FGS and cervical pre-cancer, one reported an increased risk of VIA abnormalities in women with molecular-FGS compared to those without (aOR 6.08, 95% CI 1.58 - 23.37). Three studies did not report an association between FGS and cervical pre-cancer (cytology defined (n = 2) and histology defined (n = 1)).

Conclusion: There are limited and low quality data on the risk of HR-HPV infection and cervical pre-cancer and cancer among women with FGS. Given limited data, it was not possible to confirm or exclude an association between FGS and HPV, cervical pre-cancer, and cervical cancer and additional research is needed.