Suicide mortality and suicidal ideation among patients with colorectal cancer: a systematic review and meta-analysis
Bibliographic record
Abstract
Background Receiving a cancer diagnosis is strongly associated with a higher risk of suicide. However, studies examining suicidality in patients with colorectal cancer show some inconsistencies, particularly concerning factors such as disease stage or specific diagnosis. Methods We conducted a systematic review and meta-analysis to investigate the association between colorectal cancer and suicide or suicidal ideation. EMBASE, MEDLINE, PsycINFO, Science Citation Index Expanded & Social Sciences Citation Index, CINAHL, and Google Scholar were searched from database inception to May 31, 2025. Eligible studies included longitudinal cohort or case–control designs involving patients with colorectal cancer aged ≥14 years. Control groups comprised individuals from the same population without cancer. Data were independently extracted by two researchers from published reports available in English or German. The primary outcome was suicide, defined as death from intentional self-harm; the secondary outcome was suicidal ideation, defined as non-fatal thoughts of suicide. We performed random-effects meta-analyses, assessing heterogeneity with Q and I 2 statistics and publication bias with funnel plots, Begg's, and Egger's tests. The study was registered (PROSPERO: CRD420251051277). Findings Among 4,700 records screened, 44 studies met the inclusion criteria, encompassing at least 9,385,472 patients with colorectal cancer and 13,308 suicides. Of these, 34 studies reported Standardised Mortality Ratios (SMR; colorectal cancer patients: n=8,251,924; suicides: n=12,081) and were included in the meta-analysis. After excluding studies with potential overlap in patient populations, the primary analysis was based on nine independent studies including at least 1,204,072 individuals with colorectal cancer, of whom 2,731 died by suicide. For suicidal ideation, we report the results of five individual studies. All included studies met methodological quality criteria, with a Newcastle–Ottawa Scale score of ≥7. The findings indicate a significantly increased suicide risk for patients with colorectal cancer, with a pooled SMR of 1.40 (95% CI: 1.33–1.49, I 2 = 28.17%, no evidence for publication bias) compared to the general population. Subgroup analyses revealed notably higher suicide risks among patients with metastatic disease (SMR = 3.63, 95% CI: 2.99–4.41), those under 40 years of age (SMR = 2.15, 95% CI: 1.60–2.88), and individuals diagnosed within the past six months (SMR = 2.69, 95% CI: 1.29–5.61). For suicidal ideation, primary studies did not observe differences between patients with colorectal cancer and their reference groups, such as cancer-free individuals (SMR = 1.70, 95% CI: 0.65–4.42) or patients with hepatic cancer (SMR = 1.14, 95% CI: 0.94–1.38). Interpretation Our results indicate the need for comprehensive psychological screening in patients with colorectal cancer, who show a substantially higher suicide risk than the general population. Particular attention should be given to vulnerable subgroups, including those with metastatic disease, younger patients, and those recently diagnosed. Implementing these results into clinical practice can help facilitate patient-centred, cost-effective psycho-oncological care. Notably, evidence from low- and middle-income countries remains scarce, and younger populations might be underrepresented, indicating that our results should be interpreted with caution for these groups. Funding None.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.013 | 0.032 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.036 |
| Bibliometrics | 0.008 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".