Suicidal death within a year of a cancer diagnosis: A population‐based study

BACKGROUND: The suicide risk after a new cancer diagnosis remains a controversial issue. This study examines the suicide risk within the year after a cancer diagnosis. This is the largest study to assess recent trends in suicide risk after a cancer diagnosis. METHODS: Data were obtained from the Surveillance, Epidemiology, and End Results Program. All patients diagnosed with cancer between 2000 and 2014 were selected. The event was defined as death due to suicide within the first year after a cancer diagnosis, and patients who experienced the event after their diagnosis were observed. The observed/expected (O/E) ratio was assessed as well as the excess risk per 10,000 person-years to determine the suicide risk change after the diagnosis in comparison with the general population. RESULTS: A total of 4,671,989 patients with cancer were included; 1585 committed suicide within 1 year of their diagnosis. The risk of suicide increased significantly with an O/E ratio of 2.52 and with an excess risk of 2.51 per 10,000 person-years. When the risk of suicide was studied according to the cancer site, the highest increases in the O/E ratio came after diagnoses of pancreatic cancer (8.01) and lung cancer (6.05). The risk of suicide also increased significantly after a diagnosis of colorectal cancer with an O/E ratio of 2.08. However, the risk of suicidal death did not increase significantly after breast and prostate cancer diagnoses. CONCLUSIONS: The risk of suicide increases significantly in the first year after a diagnosis of cancer in comparison with the general population, and this increase varies with the type and prognosis of cancer. Close observation and referral to mental health services, when indicated, are important for mitigating such risk.