Background: The Lancet Oncology Commission on Global Cancer Surgery recommended that access to and the quality of surgical care be improved. This study aimed to understand differences in surgical quality between emergency and elective resection among patients with potentially curative colorectal cancer.

Methods: This preplanned secondary analysis included patients undergoing only curative-intent surgery for colorectal cancer from three contemporary global prospective cohort studies (GlobalSurg-3, 5506 patients; CovidSurg-Cancer, 6719 patients; APOLLO, 876 patients) registered from 2018 to 2023. Hierarchical multilevel logistic regression models quantified associations between the urgency of surgery (elective versus emergency) and surgical quality, measured by margin-positive resection, adjusting for patient, disease, and health system factors. Bootstrap multivariable simulations evaluated effect modification by country income level, cancer stage, and location.

Results: Of the 45 699 patients registered, 13 101 across 95 countries were included in this analysis. Overall, 678 patients (5.4%) had margin-positive resections, with higher rates in the emergency than elective surgery group (13.7 versus 4.5%; P < 0.0001). In adjusted multilevel models, emergency surgery was associated with increased odds of margin-positive resections (adjusted odds ratio 2.45, 95% confidence interval (c.i.) 1.86 to 3.22), consistent across all country income groups and robust to alternative health system indicators. Bootstrap-derived absolute risk differences revealed the greatest disparities in patients with stage III-IV rectal cancers, with absolute differences of 12.6% (95% c.i. 10.2 to 15.7) in high-income countries, 19.0% (95% c.i. 13.6 to 23.9) in upper middle-income countries, and 14.1% (95% c.i. 10.9 to 16.5) in lower middle- and low-income countries. Variance decomposition demonstrated that hospital- and country-level factors accounted for 76% of the explained variation in surgical quality.

Conclusion: Emergency surgery was associated with a two- to threefold increase in the risk of margin-positive resections globally, independent of resource availability, highlighting a neglected area of global surgical practice. These findings challenge the assumption that poorer outcomes after emergency surgery are due to advanced disease stage. For patients presenting as an emergency with potentially curative resection, enhanced decision-making around resectability, ensuring specialist surgeon availability, and developing bridge-to-surgery pathways represent immediate, low-cost strategies to improve global cancer outcomes.