Screening Strategies for Colorectal Cancer: A Systematic Review of the Evidence
Bibliographic record
Abstract
BACKGROUND: Colorectal cancer is the third most common cancer in Canada. It is well recognized that there are improved survival rates if the disease is treated in its early stages, and indeed this may be a preventable disease. This paper systematically reviews the effectiveness of specific screening techniques for colorectal cancer in asymptomatic individuals at normal or above average risk. METHODS: MEDLINE was searched for articles published between January 1966 and January 2001 by using the MESH terms 'screening' and 'colorectal neoplasia'. The reference sections of review articles published before January 2001 were checked, and content experts were surveyed. The evidence was evaluated using the standardized methodology of the Canadian Task Force on Preventive Health Care. RESULTS AND DISCUSSION: For individuals at normal risk, there is evidence to support the use of annual or biennial fecal occult blood testing and flexible sigmoidoscopy for asymptomatic individuals over age 50 years. The evidence regarding whether only one or both of fecal occult blood testing and sigmoidoscopy should be performed is unclear, as is the evidence regarding the use of colonoscopy as an initial screen. For individuals at above average risk, the evidence supports either genetic testing or flexible sigmoidoscopy of individuals at risk in familial adenomatous polyposis kindreds, and screening with colonoscopy of patients in kindreds with hereditary nonpolyposis colon cancer. The evidence regarding colonoscopy for individuals who have a family history of colorectal polyps or cancer but do not fit the criteria for hereditary nonpolyposis colon cancer is unclear. Development of better risk stratification for screening is a high research priority, and further research, including randomized, controlled trials, into the effectiveness and feasibility of other screening modalities is necessary.
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 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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.004 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| 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".