Clinical Delays and Cancer Outcomes Among Younger and Older Adults With Colorectal Cancer
Bibliographic record
Abstract
Background: Colorectal cancer (CRC) patients <50 years may have clinically important delays to diagnosis and treatment. This thesis aimed to review the literature on delay intervals, describe intervals in Ontario, make comparisons to older patients, and determine the association between time to treatment and survival. Methods: Studies published after 1990 reporting any delay interval in adults <50 with CRC were included in a systematic review. A population-based cohort of adults diagnosed with CRC in Ontario from 2003-2018 was constructed. Using administrative-code based algorithms; we identified the dates of first presentation with a CRC-related symptom, first investigation, diagnosis, and treatment start. Intervals between these time points were calculated. We compared interval lengths between younger and older patients using multivariable quantile regression. Among younger adults, associations between time from presentation to treatment (overall interval), overall survival (OS), and cause-specific survival (CSS) were explored with multivariable Cox proportional hazards models. Results: 55 studies representing 188,530 younger CRC patients measured 16 unique intervals, of which diagnosis to treatment start was the most reported (12 studies; N = 170,463). In 39 studies comparing younger and older patients, 36% found significantly longer delays among younger adults. The population-based cohort included 6,853 Ontario patients <50 years. 25% had Stage IV disease. The median overall interval was 109 days (IQR 55-218). Females, patients with distal tumors, and patients with earlier stage disease had significantly longer overall intervals. Compared to adults aged 50-74, younger patients had longer intervals between presentation and diagnosis (4.3 days, 95% CI 1.3 to 7.3), and shorter intervals between diagnosis and treatment (-4.5 days, 95% CI -5.3 to -3.7). However, there was no significant difference in the overall interval (-0.6 days, 95% CI -4.3 to 3.2). Among younger patients, overall intervals >18 weeks were not associated with significantly worse OS or CSS compared to those waiting 12-18 weeks (OS HR 0.83, 95% CI 0.67-1.03; CSS HR 0.90, 95% CI 0.69-1.18). Conclusion: CRC patients <50 years have longer diagnostic intervals but overall similar times from presentation to treatment when compared to older adults. Time from presentation to treatment is not associated with survival in younger patients.
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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 | 0.003 | 0.028 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".