Are cancer patients at higher suicide risk than the general population?

The aims were to test whether suicide is more prevalent among cancer patients than among the general population, whether the association changes over time, and whether the risk depends on the severity of the cancer disease.

A register study was carried out, where standardized suicide rates for different cancer sites were analysed by sex, time periods (1965-74, 1975-84, and 1985-94), and five-year survival rates.

The setting was the Swedish population from 1965 to 1999.

The cohort studied was 1,031,919 cancer cases and 2,587,152 person-years.

The main outcome measure was the standardized mortality ratio (SMR) with the world population as standard population.

Cancer patients run a higher risk of suicide than the general population. The suicide rate ratio between male cancer patients and the general population was about 2.5 in 1965-74, which thereafter reduced to about 1.5 in 1985-94. The suicide rate among female cancer patients was in excess of 2.9 in 1965-74 and 2.3 in 1985-94. In fact, a slightly higher rate for women was observed for 1985-94 than for 1975-84. There is also a strong negative association between survival rates and suicide rates, i.e. suicide rates are higher for severe cancer sites with low survival rates.

Our findings support the hypothesis that cancer patients run greater risks of committing suicide than the general population does. The severity of the cancer increases the suicide risk. More attention to cancer patients' psychological and care situation is called for.