Table 1 Inclusion and exclusion criteria

Population

Included: adult symptomatic patients (with symptoms being indicative of cancer) presenting at primary care or patients referred with symptoms indicative of cancer

Excluded: asymptomatic patients (screening population).

Technology

Included: Diagnostic prediction models, based on 2 or more features^a, that estimate the risk of prevalent but undiagnosed colorectal cancer.

Excluded: prognostic or screening prediction models

Statistical tools that estimate the probability of developing cancer over a defined period of time.

Prediction models that did not include colorectal cancer.

Setting

Included: primary care

Excluded: secondary care; on-line tools developed for use by the general population

Study design

Included:

- any design for the development, validation or accuracy of diagnostic prediction models (as defined under ‘Technology’);

- comparative studies of diagnostic tools that assessed impact in clinical practice (Randomised controlled trials, controlled before-after, and interrupted time-series;

studies analysing national trends in cancer diagnosis before and after diagnostic tools became available)

Excluded: uncontrolled studies reporting qualitative data

Comparison

Usual care or the use of another diagnostic tool

Outcomes

For studies reporting development, validation and/or accuracy of prediction models:

Estimates of the risk of being diagnosed with cancer (e.g. ORs, HRs)

AND/OR

Any details on the development, validation or accuracy of the tool:

• Model development: method; assumptions; predictors; shrinkage; coefficient weighting

• Model evaluation (validation)

• Assessing (quantifying) model performance: discrimination (ability to discriminate participants with or without the outcome, e.g. area under the ROC curve); calibration (agreement between predicted and observed outcome); overall performance (for discrimination and calibration, e.g. R2); classification (e.g. sensitivity, specificity, predictive values)

For studies reporting evaluations of the impact of tools:

Primary outcomes

- patient-related outcome measures (including the number of cancer diagnoses, time to cancer diagnosis, stage of cancer at diagnosis, resection rates, patient health-related quality of life, other patient-reported outcome measures);

- survival;

- economic outcome measures (resource use, cost per diagnosis), cost per QALY;

Secondary outcomes

- referral patterns.

Exclude: models that report the risk of survival (or stage at diagnosis etc.)

Publication type

Included: Published in full and in English

Excluded: commentaries, letters