Suicide death among cancer patients: new data from northern Italy, systematic review of the last 22 years and meta-analysis

Background An increased risk of death by suicide in cancer patients has been documented since decades. We evaluated the risk of death by suicide in an Italian population-based cancer case series and added the results to a systematic review and meta-analysis of the literature. Methods The Italian series, including 127,042 primary cancer patients diagnosed between 1996 and 2014, was obtained from the Romagna Cancer Registry (northern Italy). Standardised mortality ratios (SMRs) were calculated. Regarding the systematic review and meta-analysis, the PubMed database was searched for English language studies published up to 2017. Fifty-seven potentially eligible papers were reviewed in full, and 19 of them were selected for analysis. The SMR was the first outcome, replaced by rate ratio if the SMR was not available. Findings In the Italian case series, an increased suicide risk was found for both sexes combined (SMR = 1.5; 95% confidence interval [CI]: 1.3–1.8), for males (SMR = 1.6; 95% CI: 1.4–1.9) but not females (SMR = 1.1; 95% CI: 0.7–1.7), for patients aged ≥55 years, with poor prognosis and advanced-stage disease and during the first year after diagnosis. The absolute excess risk of suicide was 0.9 per 10,000 patient-years. Multivariate analysis confirmed the role of univariate factors except for poor prognosis. Meta-analysis showed a strong heterogeneity between studies. The risk was significantly elevated for both sexes combined (pooled SMR = 1.7; 95% CI: 1.5–1.9), men (pooled SMR = 1.8; 95% CI: 1.6–2.0) and women (pooled SMR = 1.4; 95% CI: 1.3–1.6). There was no evidence for small-study effects. Interpretation The Italian study confirmed the previous common finding that cancer patients are at increased risk for suicide. A clinical multidisciplinary approach to support them is needed.