Comparative Risk Factors for Accidental and Suicidal Death in Cancer Patients

Background: Cancer patients appear at higher risk of accidental death and suicide. The reasons for this and how suicide and accidental death relate remain unclear. Aims: To clarify and contrast risk factors for such deaths among cancer patients. Methods: A SEER (1973-2007) analysis was conducted on 4,449,957 cancer patients comparing all causes of death (COD) to accidental and suicidal deaths through competing hazards, relative risk and proportional hazards models. SEER did not provide psychological assessments; the analysis was confined to their standard epidemiological and clinicopathological parameters. Results: 2,557,385 overall deaths yielded 16,879 (0.66%) accidents and 6,589 (0.26%) suicides. Mortality reached its highest incidence immediately after diagnosis and obeyed Pareto type II distributions. The major identifiable risk factor for suicide was male gender; for accidental death, First Nations ethnicity; and all COD, metastases. Minor factors for suicide included metastases, advanced age, and respiratory as well as head and neck tumors, whereas for accidental death they were male gender, metastases, advanced age, and brain tumors. Conclusions: Differences were observed in the risk patterns of suicide and accidental death, suggesting distinct etiologies. A high incidence of suicides and accidental deaths following diagnosis (attributed by some to stress from the diagnosis of cancer) correlated here with overall mortality and indicators of physical morbidity. Cancer patients with the above identifiable risk factors warrant supportive attention.