Long-Term Health and Economic Impacts of COVID-19 Disruptions on Bowel Cancer Inequalities in Victoria, Australia: A Modelling Study.

[INTRODUCTION] The COVID-19 pandemic significantly disrupted colorectal cancer (CRC) diagnosis and treatment globally. Most research on long-term impacts has focused on population-level outcomes, overlooking disparities in under-screened groups. This study examines the long-term effects of COVID-19 disruptions on health inequalities and healthcare costs in Victoria, Australia.

[METHODS] A Markov microsimulation model (PRISM-CRC), containing socioeconomic quintiles in Victoria, estimated health outcomes in a population aged 50-74 years from 2023-2037. The model simulated the development of CRC, considering the expected population increase in CRC cases projected by the Victorian Cancer Registry (VCR) due to COVID-19 disruptions and counterfactual scenarios with no disruptions. The model estimated CRC case numbers, CRC deaths, and total costs of CRC screening and treatment by quintile. Screened status, stage of diagnosis, and survival were obtained using a dataset linked to patients diagnosed with CRC in 2009-2021 from the VCR.

[RESULTS] Post COVID-19, CRC cases and mortality increased across all quintiles, with the greatest impacts in the most disadvantaged groups. Quintile 2 showed the largest relative cancer cases increase (21.7%), followed by quintile 1 (16.3%), whilst quintile 5 increased only 1.2%. CRC deaths rose 30.1% in quintile 1 and 28% in quintile 2, compared to 1.6% in quintile 5. Combined screening, diagnostic testing and treatment costs increased 21.4% in quintiles 1 and 24.8% in quintiles 2, versus 3.4% in quintile 5. Overall, the post-COVID-19 period intensifies the social gradient in CRC incidence, mortality, and healthcare costs.

[CONCLUSION] Our study underscores the significant impact of COVID-19 disruptions on worsening cancer inequalities. Targeted CRC screening interventions are essential to protect vulnerable populations. Enhanced demographic data from screening programs will help better understand non-participants and groups with low participation rates.