Tumor Response Evaluation after Treatment and Post-treatment Surveillance of Hepatocellular Carcinoma

ABSTRACT

Hepatocellular carcinoma is one of the most prevalent malignancies and frequent causes of death worldwide. Treatment options of hepatocellular carcinoma consist of locoregional therapy, surgical resection, liver transplantation, and systemic therapy. Assessment of tumor response is required in patients receiving locoregional and systemic therapy. The Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 is widely used tumor response evaluation criteria. However, the RECIST does not reflect the extent of tumor necrosis after some locoregional therapies and molecular targeted agents. The Modified RECIST (mRECIST), which has the concept of viable tumor, was introduced in order to overcome this problem. The mRECIST were developed on the basis of RECIST version 1.1 and only tumoral tissue showing contrast uptake in arterial phase of dynamic radiologic imaging techniques was measured to assess tumor response. Recently, immune checkpoint inhibitors have emerged as a promising therapeutic modality for the treatment of hepatocellular carcinoma. To identify tumor response after immunotherapy, immune RECIST (iRECIST) has been proposed as consensusbased criteria. After achieving complete response after curative treatment, optimal surveillance was needed to detect recurrence. Individualized surveillance schedule should be considered, taking into consideration the risk factors of the patient and the risk associated with the treatment modalities.