Injury, particularly self-inflected injury, is a significant cause of death among cancer patients and occurs at a higher rate than that of the general population. Unintended injuries rank third on the list of causes of death in the United States.
“There is evidence to suggest that suicide and death from unintentional injury share similar risk factors, such as mental distress, physical illnesses, and impaired social and physical functioning caused by treatment. Thus, we believe that it is necessary to examine not only suicide but also death due to unintentional injury among patients with cancer,” the study authors observed. “Few studies have identified increased risk of death from unintentional injury among patients with cancer.”
To that end, the researchers, reporting in JAMA Network Open, performed a retrospective cohort study assessing patients who received a first primary cancer diagnosis between Jan. 1, 1973, and Dec. 31, 2015, per data from the Surveillance, Epidemiology, and End Results (SEER) program. Mortality data gathered from the National Center for Health Statistics were used to compare cancer patients to the general U.S. population. Data analyses took place from Feb. 1, 2019, to Aug. 15, 2019. The primary outcome measure was rates and standardized mortality ratios (SMRs) of death caused by unintentional injury in cancer patients.
Final analysis included 8,271,020 cancer patients (mean [SD] age, 63.0 [15.7] years; 50.2% were female); 40,599 deaths caused by unintentional injury were recorded. The rate of death caused by unintentional injury was higher among cancer patients (81.90 per 100,000 person-years) compared to the general population (51.21 per 100,000 person-years); the SMR of death due to unintentional injury was 1.60 (95% confidence interval [CI], 1.58–1.61). The following characteristics were associated with an increased risk of death due to unintentional injury: age ≥80 years at diagnosis (rate ratio [RR]=2.91; 95% CI, 2.84–2.98; P<0.001), male sex (RR=1.69; 95% CI, 1.66–1.73; P<0.001), American Indian or Alaskan Native ethnicity (RR=1.48; 95% CI, 1.30–1.68; P<0.001), and unmarried status (RR=1.23; 95% CI, 1.18–1.28). Cancers associated with the highest rates of death caused by unintentional injury were those of the liver (200.37 per 100,000 person-years), brain (175.04 per 100,000 person-years), larynx (148.78 per 100,000 person-years), and esophagus (144.98 per 100,000 person-years). The SMRs were the highest during the immediate month following diagnosis.
The study authors concluded: “These findings suggest for the first time, to our knowledge, that the incidence of death from unintentional injury among patients with cancer is significantly higher than that in the general population in the United States. Clinicians at all levels of health care should be aware of the potential for death from unintentional injury among patients with cancer and its associated risk factors. Our results suggest the need for targeted preventive interventions of unintentional injuries among patients with cancer.”