Treatment Patterns and Outcomes of Preoperative Neoadjuvant Radiotherapy in Patients with Early-onset Rectal Cancer
Bibliographic record
Abstract
Preoperative radiotherapy for early-stage rectal cancer has risks and benefits that may impact treatment choice in young patients. We reviewed radiotherapy use and outcomes for rectal cancer by age. Patients with early-stage rectal cancer in the Canadian province of British Columbia from 2002 to 2016 were identified (n = 6,232). Baseline characteristics, treatment response, overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), and locoregional recurrence rate (LRR) were compared between patients <50 (early-onset; n = 532) and ≥50 years old (average-onset; n = 5,700). Early-onset patients were more likely to receive preoperative chemoradiotherapy than short-course radiotherapy [OR, 2.20; 95% confidence interval (CI), 1.67–2.89; P < 0.0001], but also had higher nodal (P = 0.00096) and overall clinical staging (P = 0.033). Cancer downstaging and pathologic complete response rates were similar in those receiving neoadjuvant chemoradiotherapy by age. Early-onset and average-onset patients had similar DSS (P = 0.91) and DFS (P = 0.27) in multivariate analysis unless non-colorectal deaths, which were higher in older patients, were censored in the DFS model (HR, 1.30; 95% CI, 1.01–1.68; P = 0.042). LRR also did not differ between age groups (P = 0.88). Outcomes did not differ based on radiotherapy type. Young patients with rectal cancer are more likely to present with higher staging and receive long-course chemoradiotherapy. DSS did not differ by age group; however, young patients had worse DFS when we censored competing risks of death in older patients. Significance: This population-based study suggests younger patients are more likely to receive chemoradiotherapy, potentially due to higher stage at diagnosis, and response is comparable by age.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".