Impact of Newly Introduced Population-Based Screening and the COVID-19 Pandemic on Colorectal Cancer Incidence and Characteristics: A Retrospective Cohort Study.

INTRODUCTION

In Hungary, population-based colorectal cancer (CRC) screening was introduced shortly before the onset of COVID-19 pandemic. We aimed to assess the combined impact of these 2 factors on the incidence and characteristics of CRC.

METHODS

The retrospective cohort study included all patients with newly diagnosed CRC between 2014 and 2023 and divided into prepandemic with screening (2015-2016, 2019), prepandemic without screening (2014, 2017-2018), pandemic (2020-2021), and postpandemic (2022-2023) subgroups. CRC incidence, diagnostic patterns, and tumor stage were compared across subgroups.

RESULTS

Crude CRC incidence in institution's care area was lower during pandemic (102.51 per 100,000) compared with the prepandemic with screening (117.92 per 100,000; P = 0.060) and postpandemic (120.60 per 100,000; P = 0.044) subgroups. Age-standardized incidence differed significantly only between the prepandemic with screening and pandemic subgroups (125.30 vs 105.88 per 100,000; P < 0.001). During pandemic, the proportion of early-stage (on the American Joint Committee on Cancer 0-I) cancers was significantly reduced compared with the prepandemic with screening subgroup (18.74% vs 25.08%; P = 0.048) and the proportion of T1 cancers was also lower compared with the postpandemic subgroup (6.90 vs 12.2%; P = 0.026). During pandemic, both the annual number of colonoscopies (2,706.00) and the mean number of colonoscopies required to detect 1 CRC (15.56) were markedly lower compared with the prepandemic with screening (4,590.67 and 13.97), prepandemic without screening (3,824.33 and 10.67), and postpandemic (4,573.50 and 15.50) subgroups.

DISCUSSION: The COVID-19 pandemic was associated with unfavorable changes in CRC epidemiology. Organized screening may have mitigated the negative impact during the pandemic and postpandemic periods.