[Analysis of predictive factors for non-adherence to organized screening for colorectal and breast cancers in the pre-pandemic period (2018-2019) in Lombardy Region (Northern Italy)]

Background: according to the International Agency for Cancer Research on Cancer, in 2022, breast cancer is the most common cancer in the Italian population, followed by colorectal cancer. Oncological screenings represent an effective secondary prevention strategy to counteract colorectal and breast cancers, significantly reducing mortality. In Lombardy Region (Northern Italy), screening programmes have been active since 2007, but adherence, especially in specific population subgroups, remains lower than expected.

Objectives: to analyse potential predictors of non-adherence to colorectal and breast cancer screening in the Lombardy Region during the pre-pandemic period of 2018-2019.

Design: a retrospective cohort study aimed at investigating the role of sociodemographic variables, health status, and access to the healthcare system on non-adherence to colorectal and breast cancer screening. Statistical analyses were conducted separately by each Agency for Health Protection (ATS). The results of the models were synthesized across the Lombardy region through random-effects meta-analysis.

Setting and participants: residents within the territory of each ATS in Lombardy as of 01.01.2018 and aged between 49 and 69 years at the beginning of the follow-up.

Main outcomes measures: adherence to colorectal and breast cancer screenings.

Results: during the study period, across the Lombardy Region, 2,820,138 individuals were eligible to participate in colorectal cancer screening, and 1,357,344 women were eligible to participate in breast cancer screening, with an invitation coverage of 87% and 86%, respectively.For breast cancer screening, older age, cardiopathy, chronic obstructive pulmonary disease (COPD), inflammatory bowel diseases (IBD), autoimmune diseases, and presence of a rare disease are associated with a reduced risk of non-adherence. Conversely, foreign citizenship, oncological diagnosis, transplant, chronic kidney disease/dialysis, diabetes, heart failure, arterial or cerebral vasculopathy, and presence of a neurological diagnosis are associated with significant excess risks of non-participation. For colorectal cancer screening, factors favouring adherence include female gender, older age, cardiopathy, COPD, autoimmune diseases, and having access/utilization of primary care. Non-adherence is associated with foreign citizenship, transplant, chronic kidney disease/dialysis, diabetes, heart failure, arterial or cerebral vasculopathy, IBD, neurological diseases, residence in assisted living facilities, use of integrated home care, and presence of disability.

Conclusions: this is the first study conducted in the Lombardy Region which explores the theme of equity of access to organized screenings. This analysis highlights how sociodemographic determinants, chronic conditions, and access to the healthcare and social healthcare system constitute significant risk factors for non-adherence to screening programmes. Based on the results of this analysis, communication and/or organizational change interventions will be developed to counteract inequalities in access to effective prevention procedures.