Natural history and outcomes of synchronous and metachronous colorectal cancers (CRC): A population-based analysis.
Bibliographic record
Abstract
3593 Background: Early data suggest that synchronous and metachronous CRC portend a worse prognosis when compared to solitary CRC. Our aims were to 1) characterize the clinical features and treatment patterns of synchronous and metachronous CRC and 2) compare their survival outcomes with those of solitary CRC. Methods: All patients diagnosed with non-metastatic CRC between 1999 and 2008 and referred to any 1 of 5 regional cancer centers in British Columbia, Canada were reviewed. Synchronous and metachronous CRC were defined as multiple (2 or more) distinct tumors that were diagnosed within and beyond 6 months of the date of index CRC diagnosis, respectively, during the study period. Patients with liver metastases at initial diagnosis were excluded. Kaplan-Meier and Cox regression analyses were used to estimate survival among the different CRC groups. Results: A total of 6360 patients were identified: 6147 (96%) solitary, 178 (3%) synchronous and 35 (1%) metachronous tumors; median age was 68 years (IQR 59-76); 57% were men; and 75% were ECOG 0/1 at the time of index cancer diagnosis. Baseline demographic characteristics were comparable across patients (all p>0.05). Compared with solitary CRC, synchronous and metachronous CRC more commonly affected the colon rather than the rectum (84 vs 85 vs 59%, respectively, p<0.001), but presenting symptoms, treatment approaches, and use of chemotherapy, radiation and surgery were similar among the different tumor groups (all p>0.05). In terms of survival, no differences were observed in 3-year relapse free survival (66 vs 66 vs 56%, p=0.20), 5-year cancer specific survival (69 vs 69 vs 53%, p=0.34) and 5-year overall survival (62 vs 59 vs 49%, p=0.74) for solitary, synchronous and metachronous CRC, respectively. These findings persisted after controlling for known prognostic factors, such as age and ECOG. Conclusions: In this large population-based cohort, there were no differences in survival outcomes among solitary, synchronous and metachronous CRC. Patients who present with multiple tumors in the colon or the rectum should be managed similarly to those who present with an isolated tumor.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".