Liver transplantation in treatment of colorectal liver metastases

Liver Transplantation for Colorectal Liver Metastases

Colorectal cancer is one of the most common malignancies worldwide. Approximately half of the patients diagnosed will develop colorectal liver metastases (CRLM). Liver resection has a 50% 5-year survival; however, only a fourth of cases are resectable. Unresectable CRLM has poor prognosis despite improved systemic and local ablative treatments. Liver transplantation (LT) has demonstrated a survival benefit in initial prospective clinical trials. Current use of LT for CRLM is limited to several randomized trials and high-performing centers. Improving patient selection criteria and perioperative management, LT will likely become an important part of the multidisciplinary approach to managing the metastatic disease.

Advances in liver transplantation for unresectable colon cancer liver metastasis

It is estimated that 50% of patients with colorectal cancer will develop liver metastasis. Surgical resection significantly improves survival and provides a chance of cure for patients with colorectal cancer liver metastasis (CRLM). Increasing the resectability of primary unresectable liver metastasis provides more survival benefit for those patients. Considerable surgical innovations have been made to increase the resection rate and decrease the potential risk of hepatic failure postoperation. Liver transplantation (LT) has been explored as a potential curative treatment for unresectable CRLM. However, candidate selection criteria, chemotherapy strategies, refined immunity regimens and resolution for the shortage of grafts are lacking. This manuscript discusses views on surgical indication, peritransplantation anti-tumor and anti-immunity therapy and updated advances in LT for unresectable CRLM. A literature review of published articles and registered clinical trials in PubMed, Google Scholar, and Clinicaltrials.gov was performed to identify studies related to LT for CRLM. Some research topics were identified, including indications for LT for CRLM, oncological risk, antitumor regimens, graft loss, administration of anti-immunity drugs and solutions for graft deficiency. The main candidate selection criteria are good patient performance, good tumor biological behavior and chemosensitivity. Chemotherapy should be administered before transplantation but is not commonly administered posttransplantation for preventive purposes. Mammalian target of rapamycin regimens are recommended for their potential oncological benefit, although there are limited cases. In addition to extended criterion grafts, living donor grafts and small grafts combined with two-stage hepatectomy are efficient means to resolve organ deficiency. LT has been proven to be an effective treatment for selected patients with liver-only CRLM. Due to limited donor grafts, high cost and poorly clarified oncological risks, LT for unresectable CRLM should be strictly performed under a well-organized study plan in selected patients. Some vital factors, like LT indication and anti-tumor and anti-immune treatment, remain to be confirmed. Ongoing clinical trials are expected to delineate these topics.

Molecular Immunotherapy: Promising Approach to Treat Metastatic Colorectal Cancer by Targeting Resistant Cancer Cells or Cancer Stem Cells

The immune system is able to recognize and eliminate tumor cells. Some tumors, including colorectal cancer (CRC), induce immune tolerance via different mechanisms of “immunoediting” and “immune evasion” and can thus escape immune surveillance. The impact of immunotherapy on cancer has been investigated for many years, but so far, the application was limited to few cancer types. Immuno-oncological therapeutic strategies against metastatic colorectal cancer (mCRC), the adaptive immune system activating approaches, offer a high potential for adaptation to the great heterogeneity of CRC. Moreover, novel treatment approaches are currently being tested that might specifically target the disease initiating and maintaining population of colorectal cancer stem cells (CSCs). In this review, we aim to summarize the current state of immune-oncology and tumor immunotherapy of patients with mCRC and discuss different therapeutic modalities that focus on the activation of tumor-specific T-cells and their perspectives such as tumor vaccination, checkpoint inhibition, and adoptive T-cell transfer or on the eradication of colorectal CSCs.