Trends in mortality attributable to complications of medical and surgical care among cancer patients.

BACKGROUND: Complications of medical and surgical care (CMSC) are unintentional harms from medical interventions. Their mortality burden among cancer patients remains understudied. We examined trends and disparities in CMSC-attributable mortality among U.S. cancer patients over two decades, including the COVID-19 pandemic. RESEARCH DESIGN AND METHODS: Retrospective cohort study was conducted using the SEER database for cancer patients who died of CMSC in 2003-2022. We calculated age-adjusted incidence-based mortality rates. Joinpoint regression estimated annual percent changes (APCs) across pre-pandemic (2003-2019), pandemic (2019-2021), and post-pandemic (2021-2022) periods. RESULTS: Overall mortality rate was 1.85 per million person-years (3,219 deaths). Mortality increased in 2003-2017 (APC 7.68%; 95% CI, 4.76% to 11.56%), then declined through 2019 (APC -4.81%; 95% CI, -7.86% to -1.59%). This progress reversed during pandemic (APC 6.41%; 95% CI, 3.61% to 9.40%), followed by a post-pandemic downturn (APC -34.31%). Higher mortality, faster pre-pandemic increases, or slower recoveries occurred among elderly, males, Black individuals, lower-income and nonmetropolitan residents, and localized cancer patients. CONCLUSIONS: CMSC remains an important death cause for cancer patients. Strengthening safety practices and healthcare system resilience is essential to sustain progress and improve equity in patient safety. Limitations include short post-pandemic period and unmeasured confounders.