Response assessment methodologies in hepatocellular carcinoma: Complexities in the era of local and systemic treatments

Although the mainstay of hepatocellular carcinoma (HCC) treatment has been locoregional, new systemic agents have demonstrated significant improvement in time-to-progression (TTP) and survival, leading some to postulate TTP as a surrogate of survival. While there is some rationale supporting this concept in advanced disease, complexities in HCC imaging should temper expanding this enthusiasm to early/intermediate disease until more robust evidence is available. Several examples of this lack of correlation exist in the radiofrequency ablation (RFA), chemoembolization (TACE)/radioembolization, and systemic therapy literature.