Treatment Response Evaluation and Follow-up in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the major causes of morbidity, mortality and healthcare expenditure in patients with chronic liver disease. The management of HCC is evolving because of recently introduced novel therapeutic approaches. Optimal outcome requires an early and accurate assessment of tumor response to therapy. Current imaging modalities, such as computed tomography (CT) and magnetic resonance (MR) imaging; provide reliable and reproducible anatomical data in order to demonstrate tumor burden changes. However, in the setting of novel targeted therapies and liver directed treatments, simple tumor anatomical changes can be less informative and usually appear later than biological changes. There has been a growing interest to monitor the therapeutic response, at an early phase of treatment, by measuring tumor viability and/or perfusion. Therefore the importance of tumor viability assessment is increasingly being recognized. The tumor viability measurement guidelines have recently been amended to include the measurement of only the longest diameter of the enhancing tumors to formally amend RECIST to modified RECIST (mRECIST). Viable tumor should be defined as uptake of contrast agent in the arterial phase. In this review, we discuss criteria of response evaluation in HCC and further follow-up of patients receiving curative and palliative treatment.