Minami 2015b.
| Study characteristics | |||
| Patient Sampling | Four cohorts were enrolled based on the presence of HCC or hepatitis C virus (HCV) status. Patients with positive serology for hepatitis B surface antigen were excluded. Inclusion criteria were as follows: Cohort 1: patients who developed HCC after HCV eradication using interferon (IFN)‐based therapy. These patients were enrolled from January 1990 to December 2012 at the Department of Gastroenterology of the University of Tokyo Hospital. Of the 37 patients who developed HCC after HCV eradication, 29 were defined as early stage HCC. Cohort 2:patients who did not develop HCC after HCV eradication using IFN‐based therapy. These 179 patients, who were enrolled from January 1990 to December 2012, achieved SVR, confirmed as the absence of HCC during follow‐up for more than 1 year. Cohort 3: patients who developed HCC without HCV eradication, consisting of 1185 chronic hepatitis C patients who developed HCC treated initially with radical therapies (percutaneous ethanol injection therapy, percutaneous microwave coagulation therapy, or radiofrequency ablation) from January 1990 to December 2009 at the same institution, excluding those who achieved SVR before HCC development. Cohort 4: patients without either HCC or HCV eradication. These patients were extracted from the follow‐up cohort, which was analysed for hepatitis C‐related HCC development. A matched case–control study was conducted to compare the diagnostic accuracy of AFP between SVR cohorts 1 and 2 and non‐SVR cohorts 3 and 4 to minimise the influence of non‐HCC factors on AFP levels. Age range: 56‐74. Males 79% |
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| Patient characteristics and setting | |||
| Index tests | AFP: to analyse the diagnostic accuracy of AFP for differentiating HCC cases from controls, an area under the receiver operator characteristic curve (AUROC) was calculated. The optimal cut‐off value was validated by calculating the Youden index. | ||
| Target condition and reference standard(s) | HCC: HCC was diagnosed by dynamic computed tomography (CT) or magnetic resonance imaging (MRI) with hyperattenuation in the arterial phase and washout in the late phase. As the diagnosis of HCC was not definite by CTor MRI, an ultrasound‐guided tumour biopsy was performed and pathological diagnosis made based on the Edmondson‐Steiner criteria. Early stage HCC was defined as a tumour number < 3 with each lesion < 3 cm in diameter with no evidence of vascular invasion or extrahepatic metastasis. | ||
| Flow and timing | No information on interval between index test and reference standard | ||
| Comparative | |||
| Notes | "The authors have no conflicts of interest to disclose." | ||
| Methodological quality | |||
| Item | Authors' judgement | Risk of bias | Applicability concerns |
| DOMAIN 1: Patient Selection | |||
| Was a consecutive or random sample of patients enrolled? | No | ||
| Was a case‐control design avoided? | No | ||
| Did the study avoid inappropriate exclusions? | No | ||
| Could the selection of patients have introduced bias? | High risk | ||
| Are there concerns that the included patients and setting do not match the review question? | High | ||
| DOMAIN 2: Index Test (AFP) | |||
| Were the index test results interpreted without knowledge of the results of the reference standard? | No | ||
| If a threshold was used, was it pre‐specified? | No | ||
| Could the conduct or interpretation of the index test have introduced bias? | High 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) | |||
| DOMAIN 3: Reference Standard | |||
| Is the reference standards likely to correctly classify the target condition? | Yes | ||
| Were the reference standard results interpreted without knowledge of the results of the index tests? | Yes | ||
| Could the reference standard, its conduct, or its interpretation have introduced bias? | Low 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? | Yes | ||
| Could the patient flow have introduced bias? | High risk | ||