Suicide risk among patients with cancer by sex in Japan: A population-based study

Background: In Japan, few studies have examined suicide risk for five-year relative survival rates for cancer sites. Since five-year relative survival rates differ by sex, we aim to examine suicide risk for patients with cancer separately for men and women.

Methods: We estimated the risk of suicide among patients with cancer by sex in Japan compared to the general population, using standardized mortality ratios (SMRs). Patients with cancer diagnosed between January 1, 1985–December 31, 2013 and registered in the Osaka Cancer Registry were followed-up with for up to 10 years. The outcome was suicide death. In addition, cancer sites were classified into three prognosis groups based on five-year relative survival rates: good (> 70%), moderate (40–70%), poor (< 40%).

Results: Among 623 995 patients with cancer observed for 2 349 432 person-years, 1210 patients died by suicide (867 men and 343 women). The SMRs were almost equal for men (1.66, 95% CI, 1.55-1.77) and women (1.65, 95% CI, 1.48-1.83). SMRs for cancer prognosis groups were 1.01 (95% CI, 0.84-1.22) for men and 1.47 (95% CI, 1.24-1.73) for women in the good group, 1.53 (95% CI, 1.39-1.68) for men and 1.74 (95% CI, 1.47-2.05) for women in the moderate group, and 2.54 (95% CI, 2.27-2.85) for men and 1.87 (95% CI, 1.43-2.46) for women in the poor group.

Conclusions: In this population, both sexes had higher suicide risk with poor prognosis, but the difference in SMRs between the good and poor groups was smaller for women than men.