I read the paper by Kao et al. about the association between pyogenic liver abscess (PLA) and subsequent hepatocellular carcinoma (HCC) risk with interest. By analysing the Taiwan national health insurance database, the authors have found that patients with PLA had a higher risk of HCC (standard incidence ratio 7.87, 95% CI: 5.94–10.21). Moreover, the most important issue is whether PLA is a risk factor for HCC, or an early manifestation of undiagnosed HCC.
The authors also found that standard incidence ratio of HCC was relatively higher within 1 year after the diagnosis of PLA (standard incidence ratio 257.28, 95% CI: 186.17–346.56). In view of the clinical course, PLA may be only an early manifestation of underlying HCC rather than a risk factor, which has been shown in previous studies.[2, 3]
In my opinion, PLA might be considered as a red flag sign of HCC, not a causal factor. Therefore, patients with PLA should receive an intensive surveillance for underlying HCC, especially in those with cirrhosis, hepatitis B virus infection, hepatitis C virus infection or age ≥65 years.