Hepatocellular Carcinoma Risk Scores Predict Patients Under Surveillance at Low Risk of Benefit and High Risk of Harm.

Aims: Surveillance for hepatocellular carcinoma (HCC) is recommended for patients with cirrhosis. Multiple risk scores aim to stratify HCC risk, potentially allowing individualized surveillance strategies. We sought to validate four risk scores and quantify the consequences of surveillance via the calculation of numbers needed to benefit (NNB) and harm (NNH) according to classification by risk score strata.

Methods: Data were collected on 482 patients with cirrhosis during 2013-2014, with follow-up until 31/12/2019. Risk scores (aMAP, Toronto risk index, ADRESS HCC, HCC risk score) were derived from index clinic results. The area under the receiving operating characteristic curve (AUC) was calculated for each. Additionally, per-risk strata, NNB was calculated as total surveillance ultrasounds per surveillance diagnosed early HCC (stage 0/A) and NNH as total ultrasounds performed per false positive (abnormal surveillance with normal follow-up imaging).

Results: 22 (4.6%) patients developed HCC. 77% (17/22) were diagnosed through surveillance, of which 13/17 (76%) were early stage. There were 88 false positives and no false negatives (normal surveillance result however subsequent HCC detection). Overall NNB and NNH were 241 and 36, respectively. No score was significantly superior using AUC. Patients classified as low risk demonstrated no surveillance benefit (AMAP, THRI) or had a high NNB of > 300/900 (ADRESS HCC, HCC risk score), with low NNH (24-38).

Conclusion: Given the lack of benefit and increased harm through false positives in low-risk groups, a risk-based surveillance strategy may have the potential to reduce patient harm and increase benefit from HCC surveillance.

Clinical Trials Registration: This was not a clinical trial and the study was not pre-registered.