Cancer patients had a significantly higher risk of suicide within 1 year after receiving their diagnosis versus the general population, according to a retrospective observational study, but the absolute rate remained small.
The risk of suicide increased significantly with an observed/expected (O/E) ratio of 2.52, and with an excess risk of 2.51 per 10,000 person-years, reported Hesham Hamoda, MD, MPH, of Harvard Medical School in Boston, and colleagues.
But among 1,005,825 patients who died within 1 year after a cancer diagnoses (out of 4.7 million cancer patients overall), suicide was the cause of death for 1,586 (0.16%) , the researchers wrote in Cancer.
Patients diagnosed with pancreatic or lung cancer were at the highest risk, at 8.01 and 6.05 times higher than the general population, respectively.
The risk was also heightened in patients with a poor prognosis, specifically those with distant metastases, who were at a 5.63 times higher risk of suicide, the authors added.
“If you look at some of the leading causes of death across different age groups within the entire population, you’ll find both [cancer and suicide] on the top 10 list,” Hamoda told MedPage Today. “For many patients with cancer, their actual death is not going to be a result of cancer itself, but really the emotional implications of having that diagnosis and taking their own lives.”
The findings align with previous research on a greater suicide risk in cancer patients compared with the general population, particularly within 6 months after the diagnosis, and for men, as well as for those with more severe diagnoses.
Hamoda’s group collected data from 18 registries within the Surveillance, Epidemiology, and End Results (SEER) Program, which represents nearly 30% of the U.S. population across the study’s time period. The number of deaths was obtained from the National Center for Health Statistics from 1969 to 2015, they noted. To be included in the study, cancer patients had to be diagnosed with histological confirmation from 2000 to 2014 in the U.S.
The researchers then created the O/E ratio to represent the number of observed patients who died of suicide in the study over the expected number of people who committed suicide in a similar population across the same time period, they explained.
Most of the patients who committed suicide were male (87%), white (90.2%), and older (ages 65-84 at cancer diagnosis), the authors reported.
Hamoda said several factors involved with a cancer diagnosis may be at work, such as the adverse effects of treatment (pain, fatigue), feelings of alienation, and changes in appearance (disfiguration, loss of hair). Lung cancer patients who smoked tobacco may also contend with guilt, he added.
However, some findings are not as easy to attribute to the effects of chronic illness, Hamoda said. For example, divorced patients had a higher risk of suicide than married, widowed, separated, or single patients. Since both single and divorced patients potentially lack the same social support as a married patient, the increased risk could be due to cumulative life stressors, as opposed to lacking a support system, he said.
Since the risk of suicide was highest within 2 months after diagnosis (4.81 O/E), Hamoda emphasized the importance of providing counseling or mental health services for patients diagnosed with cancer right away.
“If I had one take-home message in terms of what should be done, I would say mental health services should be embedded within oncology services, where someone with a new diagnosis can immediately and preemptively meet with someone and get emotional support,” he said.
Study limitations included its retrospective nature, the possibility that some suicides in the registry were misclassified because suicides are often underreported, and the fact that the registry did not contain information regarding anxiety or depressive disorders, which could independently influence the risk of suicide.
Hamoda disclosed no relevant relationships with industry. One co-author disclosed support from the German Academic Exchange Service.