Metabolic tumor volume predicts long-term survival after transplantation for unresectable colorectal liver metastases: 15 years of experience from the SECA study

Liver transplantation as a treatment for cancer: comprehensive review

BACKGROUND

Liver transplantation for cancer indications has gained momentum in recent years. This review is intended to optimize the care setting of liver transplant candidates by highlighting current indications, technical aspects and barriers with available solutions to facilitate the guidance of available strategies for healthcare professionals in specialized centres.

METHODS

A review of the most recent relevant literature was conducted for all the cancer indications of liver transplantation including colorectal cancer liver metastases, hilar cholangiocarcinoma, intrahepatic cholangiocarcinoma, neuroendocrine tumours, hepatocellular carcinoma and hepatic epitheloid haemangioendothelioma.

RESULTS

Transplant benefit from the best available evidence, including SECA I, SECA II, TRANSMET studies for colorectal liver metastases, various preoperative protocols for cholangiocarcinoma patients, standard, extended selection criteria for hepatocellular carcinoma and neuroendocrine tumours, are discussed. Innovative approaches to deal with organ shortages, including machine-perfused deceased grafts, living donor liver transplantation and RAPID procedures, are also explored.

CONCLUSION

Cancer indications for liver transplantation are here to stay, and the selection criteria among all cancer groups are likely to evolve further with improved prognostication of tumour biology using adjuncts such as radiomics, cancer genomics, and circulating DNA and RNA status. International prospective registry-based studies could overcome the limitations of smaller patient cohorts and lack of level 1 evidence.

Pretransplant metabolic tumor volume predicts recurrence following liver transplantation for colorectal metastasis: A multicenter study

Liver transplant (LT) for colorectal cancer liver metastases (CRLM) is increasingly popular, yet the ideal selection criteria remain unknown. Pretransplant positron emission tomography (PET) metabolic tumor volume (MTV) has been described as predicting recurrence, with a proposed cutoff of MTV ≥70 cm 3 . This approach has not been validated. Patients undergoing LT for CRLM at 2 academic transplant centers (January 1, 2017, to December 1, 2023) were included. PET-MTV was calculated by a staff radiologist from the most recent PET-scan before LT using the published protocol. Twenty-six patients were included. Median follow-up was 609 days (IQR 320-1069) and from PET to LT was 1.9 months (1.3-2.6). Nearly all (n=24, 92.3%) received living donor transplantation. Absolute recurrence rate was 30.8% (n=8). Actuarial unadjusted 1- and 2-year recurrence-free survival (RFS) were 83% (n=15/18) and 62% (n=8/13); 1- and 2-year overall survival were 100% (n=18/18) and 85% (n=11/13). The incidence of recurrence-per-year follow-up was 0.35 when MTV ≥70 cm 3 versus 0.10 if MTV <70 cm 3 ( P <0.001). Median RFS using Kaplan-Meier product-estimate was 0.83 years (95% CI: 0.43-1.23) in MTV≥70 cm 3 versus 4.1 years (95% CI: 2.90-5.22) when MTV<70 cm 3 ( p <0.001); this was also associated with improved overall survival ( p =0.003). MTV>70 cm 3 demonstrated HR=2.42 (95% CI: 2.2-62.2, p =0.006) for association with RFS on univariate Cox-proportional hazards analysis, and an AUC=0.771 (95% CI: 0.560-0.981) for predicting recurrence ( p =0.030). Nineteen patients (69.2%) had histologically viable tumors, which were associated with recurrence (43% vs. 0%, p =0.039) and reduced RFS (log-rank p =0.019). PET-MTV was associated with the presence of histologically viable tumor (AUC=0.763, 95% CI: 0.583-0.944). PET-MTV ≥70 cm 3 was associated with reduced RFS and overall survival after LT for CRLM, confirming findings from the Norway group. This is likely due to its ability to identify residual viable tumors, which are independently associated with recurrence. PET-MTV should be a key selection criterion prior to LT for CRLM.

Expanding Indications in Transplant Oncology

Liver transplantation is aptly described as the only curative treatment for cirrhosis and cirrhosis with co-morbid hepatocellular carcinoma (HCC). Its utility in the management of various other primary and secondary liver cancers is gaining traction rapidly, with more thorough assessments on broader populations continuing to emerge. Most prominently, this includes colorectal cancer liver metastasis (CRLM), cholangiocarcinoma (CCA), neuroendocrine tumors (NETs), and more. Furthermore, despite being a well described treatment for HCC for many years, growing evidence supports a change in oncological strategy for HCC, with broadened selection criteria and more advanced systemic and locoregional therapies available. Our review aims to describe the evidence supporting the expansion of indications and selection criteria for liver transplantation in various oncologic indications of primary and secondary liver tumors.

PET-Assessed Metabolic Tumor Volume Across the Spectrum of Solid-Organ Malignancies: A Review of the Literature

Solid-organ malignancies represent a significant disease burden and remain one of the leading causes of death globally. In the past few decades, the rapid evolution of imaging modalities has shifted the paradigm towards image-based precision medicine, especially in the care of patients with solid-organ malignancies. Metabolic tumor volume (MTV) is one such semi-quantitative parameter obtained from positron emission tomography (PET) imaging with 18F-fluorodeoxyglucose (FDG) that has been shown to have significant implications in the clinical oncology setting. Across various solid tumor malignancies, including lung cancer, head and neck cancer, breast cancer, esophageal cancer, and colorectal cancer, the current literature has demonstrated an association between MTV and various clinical outcomes. MTV may be used in conjunction with several existing and established clinical parameters to help inform risk stratification and treatment strategies and predict outcomes in cancer. Optimizing such volumetric parameters is paramount for advancing efforts to advance cancer care for our patients. While such advancements are made, it is important to investigate and address the limitations of MTV, including variability in terms of measurement methods, a lack of standardized cut-off values, and the impact of inherent tumor heterogeneity. Despite these limitations, which can precipitate challenges in standardization, MTV as a prognostic factor has great potential and opens an avenue for the future integration of technology into an image-based precision medicine model of care for cancer patients. This article serves as a narrative review and explores the utility and limitations of PET-MTV in various settings of solid-organ malignancy.

The prognostic value of [18F]FDG PET/CT texture analysis prior to transplantation for unresectable colorectal liver metastases

INTRODUCTION

To determine whether heterogeneity in colorectal liver metastases (CRLM) 18F fluorodeoxyglucose [18F]FDG distribution is predictive of disease-free survival (DFS) and overall survival (OS) following liver transplantation (LT) for unresectable CRLM.

METHODS

The preoperative [18F]FDG positron emission tomography/computed tomography examinations of all patients in the secondary cancer 1 and 2 studies were retrospectively assessed. Maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), and six texture heterogeneity parameters (joint entropyGLCM, dissimilarityGLCM, grey level varianceSZM, size zone varianceSZM, and zone percentageSZM, and morphological feature convex deficiency) were obtained. DFS and OS for patients over and under the median value for each of these parameters were compared by using the Kaplan Meier method and log rank test.

RESULTS

Twenty-eight out of 40 patients who underwent LT for unresectable CRLM had liver metastases with uptake above liver background and were eligible for inclusion. Low MTV (p < 0.001) and dissimilarityGLCM (p = 0.016) were correlated to longer DFS. Low MTV (p < 0.001) and low values of the texture parameters dissimilarityGLCM (p = 0.038), joint entropyGLCM (p = 0.015) and zone percentageSZM (p = 0.037) were significantly correlated to longer OS. SUVmax was not correlated to DFS and OS.

CONCLUSION

Although some texture parameters were able to significantly predict DFS and OS, MTV seems to be superior to predict both DFS and OS following LT for unresectable CRLM.

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 and 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 the USA, Europe, the 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 investigations 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 and hospital levels would be required.

Intensive locoregional therapy before liver transplantation for colorectal cancer liver metastasis: A novel pretransplant protocol

We describe a novel pre-liver transplant (LT) approach in colorectal liver metastasis, allowing for improved monitoring of tumor biology and reduction of disease burden before committing a patient to transplantation. Patients undergoing LT for colorectal liver metastasis at Cleveland Clinic were included. The described protocol involves intensive locoregional therapy with systemic chemotherapy, aiming to reach minimal disease burden revealed by positron emission tomography scan and carcinoembryonic Ag. Patients with no detectable disease or irreversible treatment-induced liver injury undergo transplant. Nine patients received liver transplant out of 27 who were evaluated (33.3%). The median follow-up was 700 days. Seven patients (77.8%) received a living donor LT. Five had no detectable disease, and 4 had treatment-induced cirrhosis. Pretransplant management included chemotherapy (n = 9) +/- bevacizumab (n = 6) and/or anti-EGFR (n = 6). The median number of pre-LT cycles of chemotherapy was 16 (range 10-40). Liver-directed therapy included Yttrium-90 (n = 5), ablation (n = 4), resection (n = 4), and hepatic artery infusion pump (n = 3). Three patients recurred after LT. Actuarial 1- and 2-year recurrence-free survival were 75% (n = 6/8) and 60% (n = 3/5). Recurrence occurred in the lungs (n = 1), liver graft (n = 1), and lungs+para-aortic nodes (n = 1). Patients with pre-LT detectable disease had reduced RFS ( p = 0.04). All patients with recurrence had histologically viable tumors in the liver explant. Patients treated in our protocol (n = 16) demonstrated improved survival versus those who were not candidates (n = 11) regardless of transplant status ( p = 0.01). A protocol defined by aggressive pretransplant liver-directed treatment and transplant for patients with the undetectable disease or treatment-induced liver injury may help prevent tumor recurrence.

Proceedings of the 28th Annual Congress of the International Liver Transplantation Society

The 2023 Joint International Congress of the International Liver Transplantation Society (ILTS), the European Liver and Intestine Transplant Association (ELITA), and the Liver Intensive Care Group of Europe (LICAGE) held in Rotterdam, the Netherlands, marked a significant recovery milestone for the liver transplant community after COVID-19. With 1159 participants and a surge in abstract submissions, the event focused on "Liver Disorders and Transplantation: Innovations and Evolving Indications." This conference report provides a comprehensive overview of the key themes discussed during the event, encompassing Hepatology, Anesthesia and Critical Care, Acute Liver Failure, Infectious Disease, Immunosuppression, Pediatric Liver Transplantation, Living Donor Liver Transplantation, Transplant Oncology, Surgical Approaches, and Machine Perfusion. The congress provided a platform for extensive discussions on a wide range of topics, reflecting the continuous advancements and collaborative efforts within the liver transplant community.

Rescue Liver Transplantation for Posthepatectomy Liver Failure: A Systematic Review and Survey of an International Experience

BACKGROUND

Rescue liver transplantation (LT) is the only life-saving option for posthepatectomy liver failure (PHLF) whenever it is deemed as irreversible and likely to be fatal. The goals were to perform a qualitative systematic review of rescue LT for PHLF and a survey among various international LT experts.

METHODS

A literature search was performed from 2000 to 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Population, Intervention, Comparison, Outcome framework, and to this, the authors' experience was added. The international online open survey included 6 cases of PHLF extracted from the literature and submitted to 976 LT experts. The primary outcome was whether experts would consider rescue LT for each case. Interrater agreement among experts was calculated using the free-marginal multirater kappa methodology.

RESULTS

The review included 40 patients. Post-LT mortality occurred in 8 (20%) cases (7/28 with proven cancer and 1/12 with benign disease). In the long term, 6 of 21 (28.6%) survivors with cancer died of recurrence (median = 38 mo) and 15 (71.4%) were alive with no recurrence (median = 111 mo). All 11 survivors with benign disease were alive and well (median = 39 mo). In the international survey among experts in LT, the percentage agreement to consider rescue LT was 28%-98%, higher for benign than for malignant disease ( P = 0.011). Interrater agreement for the primary endpoint was low, expected 5-y survival >50% being the strongest independent predictor to consider LT.

CONCLUSIONS

Rescue LT for PHLF may achieve good results in selected patients. Considerable inconsistencies of decision-making exist among LT experts when considering LT for PHLF.

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.

Transplantation for colorectal liver metastasis

PURPOSE OF REVIEW

Liver transplantation has emerged as a possible treatment for selected patients with nonresectable colorectal liver metastasis, but controversy still exists regarding optimal selection criteria and acceptable outcomes.

RECENT FINDINGS

Univariate analysis in the largest cohorts confirms that metachronous disease, Oslo score = 0-1, metabolic tumor volume (MTV) less than 70 cm 3 , and tumor burden score less than 9 are positive predictive factors for good overall survival outcomes. Some recent trials might suggest that technical resectability is not a valid exclusion criterion for patients with high tumor load and favorable prognostic scores in the transplant evaluation. Recent developments in circulation DNA technology and liquid biopsy may play a future role in the selection and monitoring of patients.

SUMMARY

Evaluation for transplant needs multidisciplinary involvement and should not be delayed until the failure of conventional oncological therapy. Larger data sets are needed to refine the selection criteria for liver transplantation in colorectal liver metastasis (CRLM).

Update to 'A Contemporary Systematic Review on Liver Transplantation for Unresectable Liver Metastasis of Colorectal Cancer'

Colorectal cancer is the second most common cause of cancer-related death worldwide, and half of patients present with colorectal liver metastasis (CRLM). Liver transplant (LT) has emerged as a treatment modality for otherwise unresectable CRLM. Since the publication of the Lebeck-Lee systematic review in 2022, additional evidence has come to light supporting LT for CRLM in highly selected patients. This includes reports of >10-year follow-up with over 80% survival rates in low-risk patients. As these updated reports have significantly changed our collective knowledge, this article is intended to serve as an update to the 2022 systematic review to include the most up-to-date evidence on the subject.

Metabolic Tumor Volume from 18F-FDG PET/CT in Combination with Radiologic Measurements to Predict Long-Term Survival Following Transplantation for Colorectal Liver Metastases

The aim of the present study is to report on the ability of metabolic tumor volume (MTV) of liver metastases from pre-transplant 18F-FDG PET/CT in combination with conventional radiological measurements from CT scans to predict long-term disease-free survival (DFS), overall survival (OS), and survival after relapse (SAR) after liver transplantation for colorectal liver metastases. The total liver MTV was obtained from the 18F-FDG PET/CT, and the size of the largest metastasis and the total number of metastases were obtained from the CT. DFS, OS, and SAR for patients with a low and high MTV, in combination with a low and high size, number, and tumor burden score, were compared using the Kaplan-Meier method and log-rank test. Patients with a low number of metastases and low MTV had a significantly longer OS than those with a high MTV, with a median survival of 151 vs. 26 months (p = 0.010). Patients with a high number of metastases and low MTV had significantly longer DFS, OS, and SAR than patients with a high MTV (p = 0.034, 0.006, and 0.026). The tumor burden score of group/zone 3, in combination with a low MTV, had a significantly improved DFS, OS, and SAR compared to those with a high MTV (p = 0.034, <0.001, and 0.006). Patients with a low MTV of liver metastases had a long DFS, OS, and SAR despite a high number of liver metastases and a high tumor burden score.

PET/CT in assessment of colorectal liver metastases: a comprehensive review with emphasis on 18F-FDG

Approximately 25% of those who are diagnosed with colorectal cancer will develop colorectal liver metastases (CRLM) as their illness advances. Despite major improvements in both diagnostic and treatment methods, the prognosis for patients with CRLM is still poor, with low survival rates. Accurate employment of imaging methods is critical in identifying the most effective treatment approach for CRLM. Different imaging modalities are used to evaluate CRLM, including positron emission tomography (PET)/computed tomography (CT). Among the PET radiotracers, fluoro-18-deoxyglucose (18F-FDG), a glucose analog, is commonly used as the primary radiotracer in assessment of CRLM. As the importance of 18F-FDG-PET/CT continues to grow in assessment of CRLM, developing a comprehensive understanding of this subject becomes imperative for healthcare professionals from diverse disciplines. The primary aim of this article is to offer a simplified and comprehensive explanation of PET/CT in the evaluation of CRLM, with a deliberate effort to minimize the use of technical nuclear medicine terminology. This approach intends to provide various healthcare professionals and researchers with a thorough understanding of the subject matter.