Suicide, other externally caused injuries and cardiovascular death following a cancer diagnosis: study protocol for a nationwide population-based study in Japan (J-SUPPORT 1902)

Suicide, other externally caused injuries, and cardiovascular disease within 2 years after cancer diagnosis: A nationwide population-based study in Japan (J-SUPPORT 1902)

BACKGROUND

This study aimed to investigate the risk of death by suicide, other externally caused injuries (ECIs), or cardiovascular disease for patients with cancer.

METHODS

We used data from the National Cancer Registry, which include the entire population in Japan. Patients diagnosed with cancer from January 1 to December 31, 2016 were included, and their follow-up period was set to 2 years. The standardized mortality ratio (SMR) of death by suicide, other ECIs, and cardiovascular disease was calculated compared with the general population. Multivariate Poisson or negative binomial regression analysis was used to quantify the adjusted relative risks of factors of interest.

RESULTS

We evaluated 1,070,876 patients with cancer. The 2-year follow-up SMR was 1.84 (95% confidence interval [CI]: 1.71-1.99) for suicide, 1.30 (95% CI: 1.24-1.37) for other ECIs, and 1.19 (95% CI: 1.17-1.21) for cardiovascular disease. The SMR was higher with shorter follow-up periods but was significant 13-24 months after cancer diagnosis. The SMRs at 0-1 month and 13-24 months, respectively, were 4.40 (95% CI: 3.51-5.44) and 1.31 (95% CI: 1.14-1.50) for suicide; 2.27 (95% CI: 1.94-2.63) and 1.27 (95% CI: 1.18-1.37) for other ECIs; and 2.38 (95% CI: 2.27-2.50) and 1.07 (95% CI: 1.04-1.10) for cardiovascular disease. The multivariate analyses showed that patients with cancers other than localized tumors had significantly high relative risks of death for each cause.

CONCLUSION

Suicide prevention countermeasures for patients with cancer, especially those with advanced disease immediately after diagnosis, are warranted.

Death by suicide, other externally caused injuries and cardiovascular diseases within 6 months of cancer diagnosis (J-SUPPORT 1902)

OBJECTIVE

To conduct the first national population-based study in Japan to characterize risks of death by suicide, other externally caused injuries and cardiovascular diseases within 6 months of cancer diagnosis.

METHODS

Cancer patients diagnosed between 1 January and 30 June 2016 and registered in the National Cancer Registry in Japan were followed up until death or 6 months after diagnosis. We calculated standardized mortality ratios and excess absolute risks per 10 000 person-years for death by suicide, other externally caused injuries and cardiovascular diseases compared with the Japanese general population.

RESULTS

Of 546 148 patients with cancer (249 116 person-years at risk), we observed 145 suicides, 298 deaths due to other externally caused injuries and 2366 cardiovascular deaths during the follow-up period. Standardized mortality ratios within 6 months were 2.68 for suicide (95% confidence interval, 2.26-3.16; excess absolute risk, 3.65), 1.49 for other externally caused injuries (95% confidence interval, 1.32-1.67; excess absolute risk, 3.92) and 1.38 for cardiovascular diseases (95% confidence interval, 1.33-1.44; excess absolute risk, 26.85). Risks were highest during the first month after cancer diagnosis (standardized mortality ratios: suicide, 4.06 [95% confidence interval, 2.90-5.53]; other externally caused injuries, 2.66 [95% confidence interval, 2.17-3.12] and cardiovascular diseases, 2.34 [95% confidence interval, 2.18-2.51]).

CONCLUSIONS

The first 6 months, and especially the first month, after cancer diagnosis were found to be a critical period for risks of death by suicide, other externally caused injuries and cardiovascular diseases. Our findings suggest that oncologists need to evaluate suicidal and cardiovascular risks of patients immediately after cancer diagnosis and provide preventive interventions.