A population-based study of the effect of FDG PET/CT in the management of liver-limited colorectal adenocarcinoma (CRC) metastases.
Bibliographic record
Abstract
3610 Background: PET/CT scans are publically funded in British Columbia for staging in liver limited metastatic CRC. However, past studies have been equivocal about the utility of PET/CT as some report as high as a 20-30% change in management while others report <10% change in management. Our primary objective was to assess the effect of the addition of PET/CT to CT scanning for the management of liver limited colorectal cancer. Methods: Patients who underwent PET/CT scan for de novo liver limited metastatic disease from 2005-2011 in the province of British Columbia were identified using the PET/CT database. Patients recently completed or currently on chemotherapy were excluded. We determined the concordance rates between CT and PET/CT scans with respect to the extra-hepatic disease, the number of lesions in the liver and the location of liver lesions. Results: 349 patients were identified. The most common indications for PET/CT scans after an initial CT scan were: detection of extrahepatic disease (77%), confirmation of the malignant nature of the liver lesions (8%) and the extent of extrahepatic disease (15%). PET/CT and CT were discordant in 39% of cases for the extent of metastatic disease. PET/CT revealed extrahepatic disease in 27% of the cases for which CT only detected liver limited disease. In contrast, 13% of patients were downstaged when CT liver lesions were demonstrated not to be FDG avid. Concordance of PET/CT and CT scans on the number and location of liver lesions was 52% and 85%, respectively. PET/CT revealed additional number of liver lesions and multilobar disease in 26% and 12% of cases, respectively. Furthermore, the median time between PET/CT and CT were 64.3 days and 64.1 days for concordant and discordant cases (p=0.88). Conclusions: PET/CT scans provided additional information compared to CT scans which could have implications for surgical management. Our study supports the utility and public funding of PET/CT in addition to CT in patients with potentially surgically curable metastatic CRC involving the liver.
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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 | 0.002 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".