Importance: Up to 30% of patients with a diagnosis of colorectal cancer (CRC) present as an emergency (an intestinal obstruction, perforation, or emergency hospital admission) (OPE). There are limited data about the association of organized, population-based colorectal cancer screening with the rate of emergency presentations.
Objective: To examine the association of CRC screening with OPE at cancer diagnosis and time trends in the rate of OPE after the start of organized CRC screening using a highly sensitive fecal occult blood test.
Design, setting, and participants: A historical cohort study was conducted among 1861 individuals 52 to 74 years of age with a diagnosis of CRC from January 1, 2007, to December 31, 2015, who lived in Winnipeg, Manitoba, a province with universal health care and an organized CRC screening program. Statistical analysis was performed from January 22, 2019, to February 26, 2020.
Exposures: Variables included prior CRC screening, era of diagnosis, cancer stage at diagnosis, tumor site in the colon, area level mean household income, primary care continuity of care, and comorbidity.
Main outcomes and measures: The primary outcomes were defined as an OPE. Logistic regression was used to evaluate factors associated with OPE at CRC diagnosis. Trends over time were calculated using Joinpoint Regression.
Results: From 2007 to 2015, 1861 individuals 52 to 74 years of age (1133 men; median age, 65.1 years [interquartile range, 60.0-70.3 years]) received a diagnosis of CRC in Winnipeg. Most individuals had good continuity of care and moderate comorbidities. Overall, 345 individuals (18.5%) had an OPE. The rate of emergency hospital admissions decreased significantly from 2007 (the start of the organized, province-wide CRC screening program) to 2015 (annual change, -7.1%; 95% CI, -11.3% to -2.8%; P = .01). There was no change in the rate of obstructions or perforations or stage IV CRCs. Individuals who were up to date for CRC screening were significantly less likely to receive a diagnosis of an OPE (odds ratio, 0.38; 95% CI, 0.28-0.50; P < .001). The results were similar after adding emergency department visits and stage IV CRC at diagnosis to the outcome.
Conclusions and relevance: This study suggests that the rate of emergency hospital admissions decreased over time for individuals who underwent CRC screening, but there was no change in the rate of obstructions and perforations. Individuals who were up to date for CRC screening were less likely to have a CRC diagnosis with an OPE.