| Study characteristics |
| Patient Sampling |
Authors have carried out a prospective study of HBV carriers in the greater Toronto area, using serum AFP and US as the screening tests for HCC. Individuals who tested positively for hepatitis B surface antigen for more than 6 months and who were over the age of 18 years were eligible. Between February 1989 and March 1994, 1069 chronic hepatitis B (CHB) carriers were referred to the Liver Cancer Screening Program. A total of 13 participants with HCC were identified. 538 participants were randomised to be screened with US and AFP (data for accuracy of US only is provided in this cohort).
Age range: 27‐51. Males 65% |
| Patient characteristics and setting |
|
| Index tests |
AFP: AFP assay (normal value < 5 ng/mL) was also performed by commercial kit (Abbott Laboratories). Cut‐off prespecified at 20 ng/mL. US: patients who were randomised to US had high‐resolution real‐time US examination of the upper abdomen. US criteria for further evaluation: liver mass |
| Target condition and reference standard(s) |
HCC: the diagnosis of HCC was confirmed by histological examination of tissue obtained from liver biopsy or surgical resection, or the combination of diagnostically increased AFP plus typical features on ultrasonography or computed tomography. |
| Flow and timing |
No information on interval between index test and reference standard. In 11 women (10%), the increase in serum AFP levels was caused by pregnancy. These were excluded from specificity and sensitivity calculations because there was no uncertainty about the cause in these cases. |
| Comparative |
|
| Notes |
No information on conflicts of interest |
| Methodological quality |
| Item |
Authors' judgement |
Risk of bias |
Applicability concerns |
| DOMAIN 1: Patient Selection |
| Was a consecutive or random sample of patients enrolled? |
Yes |
|
|
| Was a case‐control design avoided? |
Yes |
|
|
| Did the study avoid inappropriate exclusions? |
Yes |
|
|
| Could the selection of patients have introduced bias? |
|
Low risk |
|
| Are there concerns that the included patients and setting do not match the review question? |
|
|
Low concern |
| DOMAIN 2: Index Test (AFP) |
| Were the index test results interpreted without knowledge of the results of the reference standard? |
Yes |
|
|
| If a threshold was used, was it pre‐specified? |
Yes |
|
|
| Could the conduct or interpretation of the index test have introduced bias? |
|
Low risk |
|
| Are there concerns that the index test, its conduct, or interpretation differ from the review question? |
|
|
Low concern |
| DOMAIN 2: Index Test (US+AFP) |
| DOMAIN 2: Index Test (US) |
| Were the index test results interpreted without knowledge of the results of the reference standard? |
Yes |
|
|
| If a threshold was used, was it pre‐specified? |
Yes |
|
|
| Could the conduct or interpretation of the index test have introduced bias? |
|
Low risk |
|
| Are there concerns that the index test, its conduct, or interpretation differ from the review question? |
|
|
Low concern |
| DOMAIN 3: Reference Standard |
| Is the reference standards likely to correctly classify the target condition? |
No |
|
|
| Were the reference standard results interpreted without knowledge of the results of the index tests? |
No |
|
|
| Could the reference standard, its conduct, or its interpretation have introduced bias? |
|
High risk |
|
| Are there concerns that the target condition as defined by the reference standard does not match the question? |
|
|
Low concern |
| DOMAIN 4: Flow and Timing |
| Was there an appropriate interval between index test and reference standard? |
Unclear |
|
|
| Did all patients receive the same reference standard? |
No |
|
|
| Were all patients included in the analysis? |
No |
|
|
| Could the patient flow have introduced bias? |
|
High risk |
|
