Clinical and Demographic Factors Associated Suicide Risk in Patients With Colorectal Cancer

Introduction: Mental health is adversely affected by a cancer diagnosis. As the incidence of colorectal cancer (CRC) is on the rise, data regarding mental health and suicide among CRC patients is lacking. The primary aim of this study is to investigate the incidence of suicide among CRC patients in comparison to the general population. The secondary aim is to identify factors that are associated with increased risk of suicide among patients with CRC.

Methods: A cross-sectional study was conducted utilizing the Surveillance, Epidemiology, and End Results Program database from 2000 to 2018. Standardized Mortality Ratios (SMRs) were calculated for 5-y age groups. Cox's cause-specific hazards model was utilized to compare covariates that increased the risk of suicide.

Results: A total of 530,711 patients were included. 289,363 (54%) were male. Overall, there were 782 (0.15%) suicides, of which 687 (88%) occurred in males. The SMR due to suicide was significantly higher in males (SMR 1.60, 95% confidence interval [CI] 1.481-1.722; P < 0.001) including ages 35-49 ys and over 60 ys, however, not in females (SMR 1.12, 95% CI 0.91-1.375; P = 0.276). Factors independently associated with increased suicide risk included distant disease (hazard ratio [HR] 2.57; CI 1.96, 3.39; P=<0.0001), radiation (HR 1.45; CI 1.16, 1.80; P = 0.0009), and increased age (HR 1.05 per 5-y increase; CI 1.02, 1.09; P = 0.0013). Factors associated with decreased risk of suicide included non-Hispanic Black race (HR 0.27; CI 0.18, 0.41; P= <0.0001), Hispanic race (HR 0.31; 95% CI 0.21, 0.45; P=<0.0001), being married (HR 0.56; CI 0.49, 0.65; P=<0.0001), living in metropolitan area (HR 0.74; CI 0.61, 0.90; P = 0.003), and receiving chemotherapy (HR 0.71; CI 0.58, 0.86; P = 0.0001).

Conclusions: Male colorectal patients aged 35-49 ys and over 60 ys are at a higher risk of suicide than the general United States population. Understanding factors that increase a patient's risk for suicide will be important to develop strategies to mitigate this risk and improve overall mental health.