Koji Umeshita’s research while affiliated with Osaka International Cancer Institute and other places

Gastroenteropancreatic neuroendocrine tumors (NET) often metastasize to the liver. Although curative liver resection provides a favorable prognosis for patients with neuroendocrine liver metastasis (NELM), with a 5-year survival rate of 70–80%, recurrence is almost inevitable, mainly in the remnant liver. In Western countries, liver transplantation (LT) has been performed in patients with NELM, with the objective of complete removal of macro- and micro-NELMs. However, prognosis had been unsatisfactory, with 5-year overall survival and recurrence-free survival rates of approximately 50 and 30%, respectively. In 2007, the Milan criteria were proposed as indications for LT for NELM. The criteria included: (1) confirmed histology of NET-G1 or G2; (2) a primary tumor drained by the portal system and all extrahepatic diseases removed with curative resection before LT; (3) liver involvement ≤50%; (4) good response or stable disease for at least 6 months before LT; (5) age ≤ 55 years. A subsequent report demonstrated outstanding LT outcomes for NELM within the Milan criteria, with 5-year overall survival and recurrence rates of 97 and 13%, respectively. In Japan, living donor LT (LDLT) for NELM has been performed sporadically in only 16 patients by 2021 in Japan; however, no consensus has been reached on the indications or perioperative management of LDLT. This article presents the outcomes of these 16 patients who underwent LDLT in Japan and reviews the literature to clarify optimal indications and perioperative management of LDLT for NELM in the era of novel multimodal treatments.

Background In Japan, there has never been a national analysis of pediatric deceased donor liver transplantation (pDDLT) based on donor and recipient factors. We constructed a Japanese nationwide database and assessed outcomes of pDDLT focusing on the pediatric prioritization system introduced in 2018. Methods We collected data on pDDLTs (<18 years) performed between 1999 and 2021 from the Japan Organ Transplant Network and Japanese Liver Transplantation Society, identified risk factors for graft survival and compared the characteristics and graft survival in pDDLTs conducted before and after the introduction of the pediatric prioritization system. Results Overall, 112 cases of pDDLT were included, with a 1‐year graft survival rate of 86.6%. Four poor prognostic factors were identified: recipient intensive care unit stay, model for end‐stage liver disease/pediatric end‐stage liver disease score, donor cause of death, and donor total bilirubin. After the introduction of the system, allografts from pediatric donors were more reliably allocated to pediatric recipients and the annual number of pDDLTs increased. The 1‐year graft survival rate improved significantly as did pDDLT conditions indicated by the risk factors. Conclusions Under the revised allocation system, opportunities for pDDLT increased, resulting in favorable recipient and donor conditions and improved survival.

Background Validating the expanded criteria for living donor liver transplantation for hepatocellular carcinoma using national data is highly significant. The aim of this study was to evaluate the validity of the new Japanese criteria for living donor liver transplantation for hepatocellular carcinoma patients and identify factors associated with a poor prognosis using the Japanese national data set. Methods The study population comprised patients who underwent living donor liver transplantation for hepatocellular carcinoma at 37 centres in Japan between 2010 and 2018. In a nationwide survey, the overall survival and recurrence-free survival rates were evaluated based on the new Japanese criteria for applying the 5-5-500 rule when extending the indication beyond the Milan criteria. Prognostic factors within the Japanese criteria were determined using the Cox proportional hazards model. Results Patients within (485 patients) and beyond (31 patients) the Japanese criteria exhibited 5-year overall survival rates of 81% and 58% and 5-year recurrence-free survival rates of 77% and 48% respectively. Patients who met the Milan criteria, but not the 5-5-500 rule, had poorer outcomes. Multivariate analysis for 474 patients identified a neutrophil-to-lymphocyte ratio greater than or equal to 5 and a history of hepatectomy as independent risk factors. Conclusion This nationwide survey confirms the validity of the Japanese criteria. The poor prognostic factors within the Japanese criteria include a neutrophil-to-lymphocyte ratio greater than or equal to 5 and previous hepatectomy.

Objective To analyze 10,000 cases of living donor liver transplantation (LDLT) recipient data to elucidate outcomes with special reference to the graft-versus-recipient weight ratio (GRWR), based on the Japanese Liver Transplantation Society (JLTS) registry. Background The JLTS registry has been accurate and complete in characterizing and following trends in patient characteristics and survival of all patients with LDLT. Methods Between November 1989 and August 2021, 10,000 patients underwent LDLT in Japan. The procedures performed during the study period included pediatric liver transplantation (age <18 years, n = 3572) and adult liver transplantation (age ≥18 years, n=6428). Factors related to patient survival (PS) and graft survival (GS) were also analyzed. Results The GRWR was <0.7, 0.7 to <0.8, 0.8 to <3, 3 to <5, and ≥5 in 0.2%, 2.0%, 61.8%, 31.8%, and 2.6% of pediatric patients and <0.6, 0.6 to <0.7, 0.7 to <0.8, and ≥0.8 in 8.0%, 12.7%, 17.7%, and 61.5% of adult patients, respectively. Among pediatric recipients, the PS rate up to 5 years was significantly better in cases with a GRWR ≤5 than in those with a GRWR >5. When the GRWR and donor age were combined, among adult recipients 50 to 60 years old, the early PS and GS up to 5 years were significantly better in cases with a GRWR ≥0.7, than in those with a GRWR <0.7. ( P = 0.02). In adults, a multivariate analysis showed that GRWR <0.6, transplant era (<2011), donor age (>60 years), recipient age (>60 years), model for end-stage liver disease score (≥20), and center volume (<10) were significant prognostic factors for long-term PS. Conclusion Although a satisfactory long-term PS and GS, especially in the recent era (2011-2021), was achieved in the JLTS series, a GRWR ≥5 in pediatric cases and relatively old donors with a GRWR <0.7 in adult cases should be managed with caution.

Aim: Liver allografts from brain-dead donors, which were declined and were eventually not transplanted due to accompanying marginal factors, have never been surveyed in Japan. We surveyed the declined allografts and discussed the graft potential focusing on various marginal factors. Methods: We collected data on brain-dead donors between 1999 and 2019 from the Japan Organ Transplant Network. We divided their liver allografts into declined (nontransplanted) and transplanted ones, and then characterized declined ones focusing on their timepoints of decline and accompanying marginal factors. For each marginal factor, we calculated the decline rate from the number of declined and transplanted allografts, and assessed the 1-year graft survival rate from transplanted allografts. Results: A total of 571 liver allografts were divided into 84 (14.7%) declined and 487 (85.3%) transplanted ones. In the declined allografts, a majority was declined after laparotomy (n = 55, 65.5%), most of which had steatosis and/or fibrosis (n = 52). Out of the moderate steatotic (without F ≥ 2 fibrosis) allografts (n = 33), 21 were declined and 12 were transplanted, leading to a 63.6% decline rate. The latter 12 achieved a 92.9% 1-year graft survival rate after transplantation. Comparison of donor background showed no significant difference between the declined and transplanted allografts. Conclusion: Pathological abnormalities of steatosis/fibrosis seem to be the most common donor factor leading to graft decline in Japan. Allografts with moderate steatosis were highly declined; however, transplanted ones achieved promising outcomes. This national survey highlights the potential utility of liver allografts with moderate steatosis.

In developing a formula for manual use in clinical settings, simplicity is as important as accuracy. Whole-liver (WL) mass is often estimated using demographic and anthropometric information to calculate the standard liver volume or recommended graft volume in liver transplantation. Multiple formulas for estimating WL mass have been reported, including those with multiple independent variables. However, it is unknown whether multivariable models lead to clinically meaningful improvements in accuracy over univariable models. Our goal was to quantitatively define clinically meaningful improvements in accuracy, which justifies an additional independent variable, and to identify an estimation formula for WL graft weight that best balances accuracy and simplicity given the criterion. From the Japanese Liver Transplantation Society registry, which contains data on all liver transplant cases in Japan, 129 WL donor-graft pairs were extracted. Among the candidate models, those with the smallest cross-validation (CV) root-mean-square error (RMSE) were selected, penalizing model complexity by requiring more complex models to yield a ≥5% decrease in CV RMSE. The winning model by voting with random subsets was fitted to the entire dataset to obtain the final formula. External validity was assessed using CV. A simple univariable linear regression formula using body weight (BW) was obtained as follows: WL graft weight [g] = 14.8 × BW [kg] + 439.2. The CV RMSE (g) and coefficient of determination (R²) were 195.2 and 0.548, respectively. In summary, in the development of a simple formula for manually estimating WL weight using demographic and anthropometric variables, a clinically acceptable trade-off between accuracy and simplicity was quantitatively defined, and the best model was selected using this criterion. A univariable linear model using BW achieved a clinically optimal balance between simplicity and accuracy, while one using body surface area performed similarly.

Background Combined hepatocellular and cholangiocarcinoma is a rare primary liver cancer with histological features of both hepatocellular carcinoma and intrahepatic cholangiocarcinoma. Little is known about the prognostic features and molecular mechanism of cHCC-iCCA. Acylphosphatase 1 is a cytosolic enzyme that produces acetic acid from acetyl phosphate and plays an important role in cancer progression. Aims We evaluated the clinical significance of ACYP1 expression in cHCC-iCCA, HCC, and iCCA. Methods ACYP1 immunohistochemistry was performed in 39 cases diagnosed with cHCC-iCCA. The prognosis was evaluated in three different cohorts (cHCC-iCCA, HCC, and iCCA). The relationships between ACYP1 expression and cell viability, migration, invasiveness, and apoptosis were examined using siRNA methods in vitro. In vivo subcutaneous tumor volumes and cell apoptosis were evaluated after downregulation of ACYP1 expression. Results Almost half of the patients with cHCC-iCCA were diagnosed with high ACYP1 expression. In all three cohorts, the cases with high ACYP1 expression had significantly lower overall survival, and high ACYP1 expression was identified as an independent prognostic factor. Downregulation of ACYP1 reduced the proliferative capacity, migration, and invasiveness of both HCC and iCCA cells. Moreover, knockdown of ACYP1 increased the ratio of apoptotic cells and decreased the expression of anti-apoptosis proteins. In vivo tumor growth was significantly inhibited by the transfection of ACYP1 siRNA, and the number of apoptotic cells increased. Conclusion High ACYP1 expression could influence the prognosis of cHCC-iCCA, HCC, and iCCA patients. In vitro ACYP1 expression influences the tumor growth and cell viability in both HCC and iCCA by regulating anti-apoptosis proteins.

Background: Following liver transplantation (LT), allograft liver failure can be developed by various causes and requires re-LT. Hence, this study aimed to clarify the characteristics and prognostic factors of patients with allograft liver failure awaiting deceased donor LT (DDLT) in Japan. Methods: Of the 2686 DDLT candidates in Japan between 2007 and 2016, 192 adult patients listed for re-LT were retrospectively enrolled in this study. Factors associated with waitlist mortality were assessed using the Cox proportional hazards model. The transplant-free survival probabilities were evaluated using the Kaplan-Meier analysis and log-rank test. Results: The median period from the previous LT to listing for re-LT was 1548 days (range, 4-8449 days). Primary sclerosing cholangitis (PSC), which was a primary indication, showed a higher listing probability for re-LT as compared with other primary etiologies. Recurrent liver disease was a leading cause of allograft failure and was more frequently observed in the primary indication of hepatitis C virus (HCV) infection and PSC in contrast with other etiologies. Multivariate analysis identified the following independent risk factors associated with waitlist mortality: age, Child-Turcotte-Pugh (CTP) score, mode for end-stage liver disease (MELD) score, alanine aminotransferase (ALT), and causes of allograft failure. Conclusions: Recurrent HCV and PSC were major causes of allograft liver failure in Japan. In addition to CTP and MELD scores, either serum ALT levels or causes of allograft failure should be considered as graft liver allocation measures.

Aim: Using nationwide data collected over the past 20 years, we aimed to investigate deceased donor liver transplantation (DDLT) outcomes to develop a unique risk model that can be used to establish a standard for organ acceptance in Japan. Methods: Data were collected for 449 recipients aged ≥18 years who underwent DDLT between 1999 and 2019. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to develop an original risk score model for 1-year graft loss (termed the Japan Risk Index [JRI]). We developed risk indices according to recipient, donor, and surgery components (termed JRI-R, D, and S, respectively). The JRI was validated via a 5-fold cross-validation. We also compared DDLT outcomes and risk indices among Era1 (-2011), Era2 (-2015), and Era3 (-2019). Results: The 1-year graft survival rate was 89.5% and improved significantly, reaching 84.7%, 87.6%, and 93.9% in Era1, Era2, and Era3, respectively. The JRI was calculated as JRI-R (re-transplantation, Model for End-Stage Liver Disease score, medical condition in intensive care unit) × JRI-D (age, catecholamine index, maximum sodium, maximum total bilirubin) × JRI-S (total ischemic time) × 0.84. The risk model achieved a mean C-statistic value of 0.81 in the validation analysis. The risk index was significantly lower in Era3 than in Era2. Conclusion: Changes in the risk index over time indicated that avoiding risks contributed to the improved outcomes in Era3. The JRI is unique to adult DDLT in Japan and may be useful as a reference for organ acceptance in the future.