Long-Term Survival After Living-Donor Liver Transplantation for Unresectable Colorectal Metastases to the Liver: Case Report

A contemporary systematic review on liver transplantation for unresectable liver metastases of colorectal cancer

The 5-year overall survival rate of a patient with unresectable metastatic colorectal cancer is poor at approximately 14%. Similarly, historical data on liver transplantation (LT) in those with colorectal liver metastases (CRLM) showed poor outcomes, with 5-year survival rates between 12% and 21%. More recently, limited data have shown improved outcomes in select patients with 5-year overall survival rates of approximately 60%. Despite these reported survival improvements, there is no significant improvement in disease-free survival. Given the uncertain benefit with this therapeutic approach and a renewed investigational interest, we aimed to conduct a contemporary systematic review on LT for CRLM. A systematic review of the literature was performed according to the preferred reporting items for systematic reviews and meta-analysis statement. English articles reporting on data regarding LT for CRLM were identified through the MEDLINE (via PubMed), Cochrane Library, and ClinicalTrials.gov databases (last search date: December 16th, 2021) by 2 researchers independently. A total of 58 studies (45 published and 13 ongoing) were included. Although early retrospective studies suggest the possibility that some carefully selected patients may benefit from LT, there is minimal prospective data on the topic and LT remains exploratory in the setting of CRLM. Additionally, several other challenges, such as the limited availability of deceased donor organs and defining appropriate selection criteria, remain when considering the implementation of LT for these patients. Further evidence from ongoing prospective trials is needed to determine if and to what extent there is a role for LT in patients with surgically unresectable CRLM.

Liver Transplantation as a Curative Approach for Patients With Nonresectable Colorectal Liver Metastases

OBJECTIVES

Liver transplant is emerging as a potential treatment option for patients with isolated colorectal liver metastasis. In this review article, we analyzed the published literature on liver transplant outcomes in such patients.

MATERIALS AND METHODS

Four prospective studies documenting the clinical outcomes in patients with colorectal liver metastasis who underwent liver transplant were analyzed to study the feasibility of liver transplant in such patients.

RESULTS

The SECA-II trial demonstrated the highest overall survival of 100%, 83%, and 83% at 1, 3, and 5 years, respectively, and disease-free survival of 53%, 44%, and 35%, respectively, with a narrow inclusion criterion. Conversely, extended criteria for selection and donors in arm D of the same trial resulted in median overall survival and disease-free survival of 18 and 4 months, respectively.

CONCLUSIONS

Liver transplant provided more prolonged overall survival compared with other therapeutic modalities. Patients with isolated colorectal liver metastasis of less aggressive biology, good performance status, at least 6 weeks of chemotherapy, low clinical risk scores, and negative nodal disease should be considered for patient selection. Moreover, exclusion criteria consisting of patients with the right-sided primary tumor, less than 3 years to liver transplant after diagnosis, and elevation of carbohydrate antigen (CA19-9) in the presence of BRAF mutation should be explored.

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.

Reassessing the role of liver transplantation for patients with metastatic colorectal cancer to the liver

PURPOSE OF REVIEW

Early studies reported poor survival rates following liver transplantation for metastatic colorectal cancer to the liver and liver transplantation has thus traditionally been contraindicated for these patients. However, improvements in liver transplantation outcomes, immunosuppression and the treatment of colorectal cancer warrant a reassessment of the role of liver transplantation for metastatic colorectal cancer.

RECENT FINDINGS

The literature on this topic is sparse, the majority of publications being isolated cases of liver transplantation for patients with metastatic colorectal cancer to the liver. These case reports are heterogeneous, as patients received varying chemotherapy regimens and liver transplantation was performed at different times and for different indications. A prospective clinical trial out of Norway, however, has recently reported 5-year survival of 60% in a cohort of 21 patients undergoing liver transplantation for metastatic colorectal cancer to the liver. These results are significantly better than standard of care chemotherapy and comparable with outcomes for other indications for liver transplantation.

SUMMARY

The role of liver transplantation for patients with metastatic colorectal cancer to the liver needs to be further elucidated and defined by ongoing clinical trials and experience with living donor liver transplantation.

The Potential Role of Liver Transplantation as a Treatment Option in Colorectal Liver Metastases

Liver resection is the only potentially curative treatment option in patients with liver metastases from colorectal cancer, but only about 20% of the patients are resectable. Liver transplantation of patients with unresectable liver metastases was attempted in the early era but it was abandoned due to poor survival. During the last decade, several case reports, a controlled pilot study, and a retrospective cohort study indicated that prolonged disease-free survival and overall survival can be obtained in a proportion of these patients. Strict selection criteria have not yet been well defined, but tumor load, response to chemotherapy, pretransplant carcinoembryonic antigen level, and time interval from resection of the primary tumor to transplant are all factors related to outcome. Carefully selected patients may obtain 5-year overall survival that approaches conventional indications for liver transplant. The scarcity of liver grafts is a significant problem, but this can possibly to some extent be addressed by use of extended criteria grafts and novel surgical techniques. There is an increasing interest in liver transplantation in these patients in the transplant community, and currently 4 clinical trials are active and are recruiting.

Liver transplantation for unresectable colorectal liver metastases: A systematic review

The use of liver transplantation (LT) for liver metastases attempted in the early 1990's was associated with poor perioperative outcomes and unacceptably low overall survival. Recently, there has been renewed interest in LT as a treatment option for colorectal liver metastases (CLM) in countries where organ supply is high. To date, no meticulous analysis about the efficacy, safety and outcomes of LT in CLM patients has been published. We present the first systematic review on the subject.

Liver transplantation in treatment of colorectal liver metastases

Surgical resection is the only curative modality for colorectal liver metastases (CLM) and 5-year overall survival after resection is about 40%. Nonresectable CLM is not curable and 5-year overall survival is currently about 10%. Before 1995, several liver transplantations for CLMs were performed, but outcome was poor (5-year survival rate: 18%). Liver transplantation for CLMs was abandoned and CLMs were even considered a contraindication to the procedure. Since then, the survival rate after liver transplantation in general has improved by almost 30%. In a prospective pilot study of liver transplantation for nonresectable CLM, a 5-year overall survival rate of 60% was demonstrated, however 19 of 21 patients experienced recurrence of disease. Here, current knowledge and ongoing research in this field is reviewed, and the potential role for liver transplantation as one of several treatment modalities for CLM discussed.

Surgical options for initially unresectable colorectal liver metastases

Although the frontiers of liver resection for colorectal liver metastases have broadened in recent decades, approximately 75% of these patients present with unresectable metastases at the time of their diagnosis. In the past, these patients underwent only palliative treatment, without the chance of a cure. In the previous two decades, several therapeutic strategies have been developed that render resectable those metastases that were initially unresectable, thus offering the chance of long-term survival and even a cure to these patients. The oncosurgical modalities that are available include liver resection following portal vein ligation/embolization, “two-stage” liver resection, one-stage ultrasonically guided liver resection, hepatectomy following conversion chemotherapy, and liver resection combined with thermal ablation. Moreover, in recent years, certain authors have recommended the revisiting of the concept of liver transplantation in highly selected patients with unresectable colorectal liver metastases and favorable prognostic factors. By employing such therapies, the number of patients with colorectal liver metastases who undergo a potentially curative treatment could increase to 40%. The safety profile of these approaches is acceptable (morbidity rates as high as 45%, mortality rates of less than 5%). Furthermore, the 5-year survival rates (approximately 30%) are significantly increased over those that were achieved with palliative treatment.