Risk of malignant disease in 1-year sepsis survivors, a registry-based nationwide follow-up study

Background: Cancer and sepsis share risk factors, and sepsis patients may have impaired immune response and increased morbidity long after intensive care. This study aimed to assess whether sepsis survivors are at increased risk for cancer. Our objective was to assess the incidence of new cancer in 1-year sepsis survivors and test the hypothesis that it is higher than that of the general population. Methods: We obtained data on ICU admissions of adult patients from Swedish Intensive care registry (SICR) from 2005 to 2017. We included patients with an explicit ICD-10 code for sepsis for the primary ICU admission. We obtained data on cancer diagnoses (2001–2018), death (2005–2018) and emigration (2005–2018) from Cancer and Cause of death and National Patient Registry databases of the National Board of Health and Welfare; age and sex-specific cancer incidence rates in Sweden from NORDCAN registry from 2006 to 2018. One-year survivors formed the final cohort, that was followed for new cancer diagnoses until death, emigration, or end of 2018, whichever came first. The main outcome measure was standardized incidence rate ratio (SIR) to compare the incidence of cancer in 1-year sepsis survivors to that in the general population (NORDCAN). We also performed several sensitivity analyses. Results: In a cohort of 18,550 1-year survivors, 75,427 person years accumulated during a median follow-up (FU) of 3.36 years (IQR 1.72–5.86), 6366 (34.3%) patients died, and 1625 (8.8%) patients were diagnosed with a new cancer after a median FU of 2.51 (IQR 1.09–4.48) years. The incidence ratio of any new cancer over the whole FU was 1.31 (95% CI 1.23–1.40) for men and 1.74 (95% CI 1.61–1.88) for women. The difference in incidence rates persisted in several sensitivity analyses. The SIRs were highest in cancers of gastrointestinal tract, genital organs, and skin. Conclusion and relevance: Compared to general population, incidence of cancer is increased in 1-year sepsis survivors. Variation in the findings depending on follow-up time suggests that factors other than sepsis alone are involved. Surveillance for malignant disease may be warranted in sepsis survivors. Graphical abstract: [Figure not available: see fulltext.].