Liver transplantation in patients with liver metastases from neuroendocrine tumors

Single center outcomes from parenchymal-sparing resections and microwave ablations for neuroendocrine tumor liver metastases

BACKGROUND

Reported outcomes after surgical debulking in patients with advanced neuroendocrine tumor liver metastases (NETLM) are sparse.

METHODS

NETLM patients that underwent surgical debulking from 2019 to 2021 were reviewed. Trends in perioperative liver function, complications, symptom response, and progression-free survival were examined.

RESULTS

1069 liver lesions were debulked from 53 patients using a combination of parenchymal-sparing resections (PSR) and ultrasound-guided microwave ablations (MWA). Post-operative transaminitis and thrombocytopenia were common, and severity correlated with increasing number of lesions. Laboratory markers for synthetic liver function did not differ according to the number of lesions debulked. 13% of patients sustained a Clavien-Dindo grade 3 or 4 complication which was not associated with the number of lesions targeted. All patients with preoperative symptoms had improvement after surgery. Median time to progression was 10.9 months.

CONCLUSIONS

PSR with MWA for large numbers of NETLM is safe and effective for symptom control and does not affect synthetic liver function.

LIVER TRANSPLANT FOR METASTATIC NEUROENDOCRINE TUMORS: A SINGLE-CENTER REPORT

BACKGROUND

Neuroendocrine tumors are rare neoplasms of uncertain biological behavior. The liver is one of the most common sites of metastases, occurring in 50% of patients with metastatic disease.

AIMS

To analyze a clinical series in liver transplant of patients with neuroendocrine tumors metastases.

METHODS

A retrospective descriptive study, based on the review of medical records of patients undergoing liver transplants due to neuroendocrine tumor metastases in a single center in northeast Brazil, over a period of 20 years (January 2001 to December 2021).

RESULTS

During the analyzed period, 2,000 liver transplants were performed, of which 11 were indicated for liver metastases caused by neuroendocrine tumors. The mean age at diagnosis was 45.09±14.36 years (26-66 years) and 72.7% of cases were females. The most common primary tumor site was in the gastrointestinal tract in 64% of cases. Even after detailed investigation, three patients had no primary tumor site identified (27%). Overall survival after transplantation at one month was 90%, at one year was 70%, and five year, 45.4%. Disease-free survival rate was 72.7% at one year and 36.3% at five years.

CONCLUSIONS

Liver transplantation is a treatment modality with good overall survival and disease-free survival results in selected patients with unresectable liver metastases from neuroendocrine tumors. However, a rigorous selection of patients is necessary to obtain better results and the ideal time for transplant indication is still a controversial topic in the literature.

Liver transplantation in gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are part of a heterogeneous group of tumors located in organs such as the gastrointestinal tract (GIT), lungs, thymus, thyroid, and adrenal glands. The most prevalent sites are the small intestine, cecal appendix, and pancreas. More than 50% of these tumors are associated with metastases at the time of diagnosis. Neuroendocrine tumors are classified according to the degree of cell differentiation and the histopathological proliferation index of the lesion. Neuroendocrine tumors can be well differentiated or poorly differentiated. G3 tumors are characterized by Ki-67 expression greater than 20% and can be either well differentiated (G3 NET) or poorly differentiated (G3 NEC). Neuroendocrine carcinoma (NEC G3) is subdivided into small-cell and large-cell types. When neuroendocrine tumors present clinical and compressive symptoms, carcinoid syndrome is evident. Carcinoid syndrome occurs when the tumor produces neuroendocrine mediators that cannot be metabolized by the liver due to either the size of the tumor or their secretion by the liver itself. Several therapeutic strategies have been described for the treatment of metastatic neuroendocrine tumors, including curative or palliative surgical approaches, peptide receptor radionuclide therapy, percutaneous therapy, systemic chemotherapy, and radiotherapy. Liver surgery is the only approach that can offer a cure for metastatic patients. Liver metastases must be completely resected, and in this context, orthotopic liver transplantation has gained prominence for yielding very promising outcomes in selected cases. The aim of this study is to review the literature on OLT as a form of treatment with curative intent for patients with gastroenteropancreatic neuroendocrine tumors with liver metastasis.

Novel Benchmark Values for Redo Liver Transplantation: Does the Outcome Justify the Effort?

OBJECTIVE

To define benchmark cutoffs for redo liver transplantation (redo-LT).

BACKGROUND

In the era of organ shortage, redo-LT is frequently discussed in terms of expected poor outcome and wasteful resources. However, there is a lack of benchmark data to reliably evaluate outcomes after redo-LT.

METHODS

We collected data on redo-LT between January 2010 and December 2018 from 22 high-volume transplant centers. Benchmark cases were defined as recipients with model of end stage liver disease (MELD) score ≤25, absence of portal vein thrombosis, no mechanical ventilation at the time of surgery, receiving a graft from a donor after brain death. Also, high-urgent priority and early redo-LT including those for primary nonfunction (PNF) or hepatic artery thrombosis were excluded. Benchmark cutoffs were derived from the 75th percentile of the medians of all benchmark centers.

RESULTS

Of 1110 redo-LT, 373 (34%) cases qualified as benchmark cases. Among these cases, the rate of postoperative complications until discharge was 76%, and increased up to 87% at 1-year, respectively. One-year overall survival rate was excellent with 90%. Benchmark cutoffs included Comprehensive Complication Index CCI ® at 1-year of ≤72, and in-hospital and 1-year mortality rates of ≤13% and ≤15%, respectively. In contrast, patients who received a redo-LT for PNF showed worse outcomes with some values dramatically outside the redo-LT benchmarks.

CONCLUSION

This study shows that redo-LT achieves good outcome when looking at benchmark scenarios. However, this figure changes in high-risk redo-LT, as for example in PNF. This analysis objectifies for the first-time results and efforts for redo-LT and can serve as a basis for discussion about the use of scarce resources.

Neuroendocrine liver metastases: a contemporary review of treatment strategies

Well-differentiated neuroendocrine tumors (NETs) are globally increasing in prevalence and the liver is the most common site of metastasis. Neuroendocrine liver metastases (NELM) are heterogeneous in clinical presentation and prognosis. Fortunately, recent advances in diagnostic techniques and therapeutic strategies have improved the multidisciplinary management of this challenging condition. When feasible, surgical resection of NELM offers the best long-term outcomes. General indications for hepatic resection include performance status acceptable for major liver surgery, grade 1 or 2 tumors, absence of extrahepatic disease, adequate size and function of future liver remnant, and feasibility of resecting >90% of metastases. Adjunct therapies including concomitant liver ablation are generally safe when used appropriately and may expand the number of patients eligible for surgery. Among patients with synchronous resectable NELM, resection of the primary either in a staged or combined fashion is recommended. For patients who are not surgical candidates, liver-directed therapies such as transarterial embolization, chemoembolization, and radioembolization can provide locoregional control and improve symptoms of carcinoid syndrome. Multiple systemic therapy options also exist for patients with advanced or progressive disease. Ongoing research efforts are needed to identify novel biomarkers that will define the optimal indications for and sequencing of treatments to be delivered in a personalized fashion.

Surgical management of pancreatic neuroendocrine liver metastases

Pancreatic neuroendocrine tumors (PNET) are a heterogeneous group of neoplasms that vary in their clinical presentation, behavior and prognosis. The most common site of metastasis is the liver. Surgical resection of neuroendocrine liver metastases (NELM) is thought to afford the best long-term outcomes when feasible. Initial preoperative workup should include surveillance for carcinoid syndrome, screening for evidence of liver insufficiency, and performance of imaging specific to neuroendocrine tumors such as a somatostatin receptor positron emission tomography scan. Standard surgical principles apply to hepatic surgery for NELM, namely prioritizing low central venous pressure anesthesia, minimizing blood loss, knowledge of liver anatomy, generous use of intraoperative ultrasound, as well as safe parenchymal transection techniques and practices to avoid bile leakage. Knowledge of established prognostic factors may assist with patient selection, which is important for optimizing short- and long-term outcomes of hepatic resection. Adjunct therapies such as concomitant liver ablation are used frequently and are generally safe when used appropriately. For patients with synchronous resectable NELM, resection of the primary either in a staged or combined fashion is recommended. Primary tumor resection in the setting of unresectable metastatic disease is more controversial, however generally recommended if morbidity is acceptable. For patients who are not surgical candidates, due to either patient performance status or burden of liver disease, several liver-directed therapies such as transarterial embolization, chemoembolization, and radioembolization are available to assist with locoregional control, extend progression-free survival (PFS), and improve symptoms of carcinoid syndrome. Multiple systemic therapy options exist for patients with metastatic PNET which are often prioritized for those patients with advanced or progressive disease. A systematic approach in a multi-disciplinary setting is likely to result in the best long-term outcomes for patients with pancreatic NELM. Ongoing research is needed to determine the optimal patient selection for hepatic surgery as well as the ideal treatment sequencing for those patients with NELM.