Invasive cervical cancer, precancerous lesions, and cervical screening participation among women with mental illness in Sweden: a population-based observational study.

Background: WHO aims to eliminate cervical cancer. Whether women with mental illness constitute a group at high-risk and require targeted prevention initiatives remains unknown. We aimed to assess whether women with severe mental illness, psychiatric or neurodevelopmental disorders, have an increased risk of invasive cervical cancer, and an increased risk of precancerous lesions and a lower degree of participation in cervical screening compared with women without severe mental illness.

Methods: In this population-based observational study, 4 112 598 women from 1973 to 2018 in Sweden were included to compare the risk of invasive cervical cancer, high-grade precancerous cervical lesions (CIN2+), and degree of participation in cervical screening (defined as the proportion of time covered by screening during a period when cervical screening is recommended) between women with and without mental illness. We focused on severe mental illness (ie, diagnosed in specialised psychiatric care) and also investigated milder mental illness (ie, use of psychotropic medications prescribed in primary care without specialist diagnosis) as secondary exposure. In two nested case-control studies, we defined the cases as women who have a diagnosis of invasive cervical cancer or CIN2+, and randomly selected individually matched controls from women who did not have these diagnoses.

Findings: Women with a specialist diagnosis of mental illness had a higher risk of invasive cervical cancer (hazard ratio 2·39, 95% CI 2·22-2·57) and CIN2+ (2·22, 2·18-2·26) and a 5·0% (4·8-5·2) lower cervical screening participation compared with matched controls. The risk increment of invasive cervical cancer and CIN2+ was greatest for substance misuse, whereas the screening reduction was greatest for intellectual disability and autism. In contrast, women who used prescribed psychotropic medications without specialist diagnosis had slightly higher screening participation and higher risk of CIN2+ but lower risk of invasive cervical cancer than women with neither specialist diagnosis nor medication use.

Interpretation: Women with severe mental illness participate less in screening and experience a higher risk of cervical neoplasia. Refined approaches are needed to better target these women in the elimination agenda of cervical cancer.

Funding: Swedish Cancer Society.