SOULMATE: the Swedish study of liver transplantation for isolated colorectal cancer liver metastases not suitable for operation or ablation, compared to best established treatment-a randomized controlled multicenter trial

Role of locoregional therapy including liver transplantation in liver-only metastatic colorectal cancer: a review Paper

INTRODUCTION

Resection of primary tumor and liver metastases is the gold standard for colorectal cancer with liver-only metastases (CRLM). Although treatment options have expanded to enable conversion of unresectable to resectable CRLM, about 40% of patients will have definitively unresectable disease. Major advances in surgical techniques, immunosuppressive protocols and patient selection criteria for liver transplantation have resulted in improved outcomes.

AREAS COVERED

A literature search has been conducted in Pubmed for articles published between 2014 - 2024. This review paper comments on current liver-directed treatment options for CRLM: resection, percutaneous ablation, conversion-chemotherapy, TACE, SIRT and SABR. We explore evidence for liver transplantation in patients with unresectable CRLM, comment on possible limitations for implementation in clinical practice and give an overview of the current guidelines on liver transplantation in USA, Europe, United Kingdom and Australia/New Zealand.

EXPERT OPINION

The recent randomized TRANSMET trial, investigating liver transplantation versus chemotherapy in unresectable CRLM, shows promising 5-year OS reaching similar values as for other accepted liver transplantation indications. Further investigation with RCTs to investigate reproducibility and feasibility in clinical practice are needed. Before liver transplantation can be implemented as a standard treatment option, reorganizations at federal, regional as hospital level would be required.

Liver transplantation for tumor entities

PURPOSE OF REVIEW

Tumor entities represent an increasing indication for liver transplantation (LT). This review addresses the most contentious indications of LT in transplant oncology.

RECENT FINDINGS

Patient selection based on tumor biology in LT for colorectal cancer liver metastases (CRLM) demonstrated promising long-term outcomes and preserved quality of life despite high recurrence rates. In selected cases, LT for intrahepatic cholangiocarcinoma (iCCA) is feasible, with acceptable survival even in high-burden cases responsive to chemotherapy. LT following a strict neoadjuvant protocol for perihilar cholangiocarcinoma (pCCA) resulted in long-term outcomes consistently surpassing benchmark values, and potentially outperforming liver resection.

SUMMARY

While preliminary results are promising, prospective trials are crucial to define applications in routine clinical practice. Molecular profiling and targeted therapies pave the way for personalized approaches, requiring evolving allocation systems for equitable LT access.

Evolution and current trends in the management of colorectal cancer liver metastasis

Metastatic colorectal cancer (mCRC) is a major cause of cancer-related death, with a 5-year relative overall survival of up to 20%. The liver is the most common site of distant metastasis in colorectal cancer (CRC), with about 50% of CRC patients metastasizing to their liver over the course of their disease. Complete liver resection is the primary modality of treatment for resectable colorectal cancer liver metastasis (CRLM), with an overall 5-year survival rate of up to 58%. However, only 15% to 20% of patients with CRLM are deemed suitable for resection at presentation. For unresectable diseases, the median survival of patients remains low even with the best chemotherapy. In recent decades, the management of CRLM has continued to evolve with the expansion of resection criteria, novel targeted systemic therapies, and improved locoregional therapies. However, due to the heterogeneity of the CRC patient population, the optimal evaluation of treatment options for CRLM remains complex. Therefore, effective management requires a multidisciplinary team to help define resectability and devise a personalized treatment approach, from the initial diagnosis to the final treatment.

Liver transplantation as an alternative for the treatment of non-resectable liver colorectal cancer: Advancing the therapeutic algorithm

Colorectal cancer is a leading cause of cancer-related mortality, with nearly half of the affected patients developing liver metastases. For three decades, liver resection (LR) has been the primary curative strategy, yet its applicability is limited to about 20% of cases. Liver transplantation (LT) for unresectable metastases was attempted unsuccessfully in the 1990s, with high rates of perioperative death and recurrence. There is now more interest in this strategy due to improvements in systemic therapies and surgical techniques. A significant study conducted by the Oslo group showed that patients receiving liver transplants had a 60% chance of survival after five years. Significantly better results have been achieved by using advanced imaging for risk stratification and further refining selection criteria, especially in the Norvegian SECA trials. This review carefully charts the development and history of LT as a treatment option for colorectal cancer liver metastases. The revolutionary path from the early days of exploratory surgery to the current situation of cautious optimism is traced, highlighting the critical clinical developments and improved patient selection standards that have made LT a potentially curative treatment for such challenging very well selected cases.

Liver Transplantation for Unresectable Colorectal Liver Metastasis: Perspective and Review of Current Literature

The treatment of unresectable colorectal liver metastasis (CRLM) has previously been limited to palliative chemotherapy. Traditionally, the role of liver transplant has not been associated with sufficient survival to justify a patient undergoing a major operation with the associated requirement for postoperative immunosuppression. With improvements in chemotherapy options, a certain subset of patients can experience stable disease for years, which has prompted investigation into the role of liver transplant in these patients. Several recent studies have shown promising results in well-selected patients, with posttransplant survival approaching that of liver transplant recipients for other diseases. Here, we present a review of the data and current protocols for liver transplant for unresectable CRLM.

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.

Treatment of Oligometastatic GI Cancers

Oligometastatic state is believed to potentially represent a transitional stage between early, locoregional state disease and widely metastatic disease. Historically, locoregional approaches, particularly in advanced colorectal cancers, have demonstrated efficacy in select patients with limited burden of metastatic disease. Recent strides in systemic therapies, including biomarker-based treatments and immunotherapy, alongside innovations in surgical techniques and novel locoregional approaches such as stereotactic radiotherapy and ablation, have ushered in a new era of therapeutic possibilities across all oligometastatic GI cancers. Despite these advancements, there remains a significant gap in high-quality prospective evidence guiding patient selection and treatment decisions across various disease types. Ongoing clinical trials are anticipated to provide crucial insights into oligometastatic states, fostering the refinement of disease-specific oligometastatic state definitions and treatment algorithms. This article reviews existing data on the management of oligometastatic GI cancer, summarizes current state of knowledge for each disease state, and provides updates on ongoing studies in this space.

Liver Transplantation for Colorectal Liver Metastases: Is It Appropriate?

Colorectal cancer with liver metastases is a condition with significant morbidity and mortality that affects many people around the world. Many treatments exist to target liver metastases, including surgical resection, chemotherapy, nonsurgical liver-directed therapies, and liver transplantation. The field of transplant oncology is emerging as a promising alternative to palliative chemotherapy alone in appropriately selected patients. Though few clinical trials have been completed to evaluate safety of liver transplant for colorectal cancer metastases, there are several ongoing trials to hopefully make transplant a viable option for more patients with limited options.

Updates and Expert Opinions on Liver Transplantation for Gastrointestinal Malignancies

Transplant oncology is a relatively new field in which transplantation is used to treat patients who would otherwise be unresectable. New anticancer treatment paradigms using tumor and transplant immunology and cancer immunogenomics are emerging. In turn, liver transplantation (LT) has become a potential therapy for certain patients with colorectal cancer (CRC) with liver metastasis, hepatocellular (HCC), cholangiocarcinoma (CCA), and metastatic neuroendocrine tumor (NET) of the liver. Although there are established criteria for LT in HCC, evidence regarding LT as a treatment modality for certain gastrointestinal malignancies is still debated. The aim of this review is to highlight updates in the role of LT for certain malignancies, including HCC, metastatic CRC, hilar CCA, and neuroendocrine tumor (NET), as well as contextualize LT use and discuss controversies in transplant oncology.

Transplant for colorectal cancer liver metastases

Colorectal cancer with unresectable liver metastases has significant mortality when treated with chemotherapy alone. In appropriately selected patients, liver transplant is emerging as a treatment alternative for this population. Some key clinical trials, including SECA-I and SECA-II, have shown promising survival results: more trials are being conducted to evaluate safety of this practice.