Presentation and survival among patients with colorectal cancer before the age of screening: a systematic review and meta-analysis
Bibliographic record
Abstract
Background: The incidence of colorectal cancer in North America is rising among patients younger than 50 years. Available data are conflicting regarding presentation and outcomes in this population. This review aimed to synthesize literature regarding young patients with colorectal cancer with respect to patient demographics, disease extent and survival, compared with patients older than 50 years. Methods: We searched Medline, Embase, the Cochrane Central Register of Controlled Trials and PubMed for articles published between 1990 and the time of search. Articles comparing North American patients with colorectal cancer younger and older than 50 years were eligible for inclusion. We used a random-effects model to pool odds ratios. Results: Eight retrospective studies were eligible for inclusion (n = 790 959). Mean age was 42.6 years (standard deviation [SD] 5.07) in the younger group, and 69.1 years (SD 9.25) in the older group. Young patients were more likely to present with regional (odds ratio [OR] 1.27, 95% confidence interval [CI] 1.16-1.40) and distant disease (OR 1.47, 95%CI 1.30-1.67). Considering patients at all stages of disease, differences in 5-year overall survival (OR 1.54, 95%CI 0.96-2.47) and cancer-specific survival (OR 1.01, 95%CI 0.91-1.13) were not statistically significant between groups. However, when controlling for disease extent, 5-year cancer-specific survival was significantly higher among young patients with local (OR 1.69, 95%CI 1.43-1.99), regional (OR 1.37, 95%CI 1.16-1.63) and distant disease (OR 1.79, 95%CI 1.45-2.21). Conclusion: North American patients presenting with colorectal cancer before the age of 50 years are more likely to have advanced disease. Although overall and cancer-specific survival is not significantly different between these groups, younger patients have improved survival when controlling for cancer stage.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.008 | 0.026 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.017 | 0.032 |
| Bibliometrics | 0.006 | 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".