Conversion therapy in liver transplantation for hepatocellular carcinoma: What's new in the era of molecular and immune therapy?

Hepatocellular carcinoma (HCC) is the sixth most common cancer globally, with limited therapies and unsatisfactory prognosis once in the advanced stages. With promising advances in locoregional and systematic treatments, fast development of targeted drugs, the success of immunotherapy, as well as the emergence of the therapeutic alliance, conversion therapy has recently become more well developed and an effective therapeutic strategy. This article aimed to review recent developments in conversion therapy in liver transplantation (LT) for HCC.We searched for relevant publications on PubMed before September 2022, using the terms "HCC", "liver transplantation", "downstaging", "bridging treatment" and "conversion therapy."Conversion therapy was frequently represented as a combination of multiple treatment modalities to downstage HCC and make patients eligible for LT. Although combining various local and systematic treatments in conversion therapy is still controversial, growing evidence has suggested that multimodal combined treatment strategies downstage HCC in a shorter time, which ultimately increases the opportunities for LT. Moreover, the recent breakthrough of immunotherapy and targeted therapy for HCC also benefit patients with advanced-stage tumors.In the era of targeted therapy and immunotherapy, applying the thinking of transplant oncology to benefit HCC patients receiving LT is a new topic that has shed light on advanced-stage patients. With the expansion of conversion therapy concepts, further investigation and research is required to realize the full potential of conversion treatment strategies, including accurately selecting candidates, determining the timing of surgery, improving the conversion rate, and guaranteeing the safety and long-term efficacy of treatment.