Foremost Concepts in Mechanisms of De Novo Post-Liver Transplantation Malignancy

A Reduction of Calcineurin Inhibitors May Improve Survival in Patients with De Novo Colorectal Cancer after Liver Transplantation

Background and Objectives: After liver transplantation (LT), long-term immunosuppression (IS) is essential. IS is associated with de novo malignancies, and the incidence of colorectal cancer (CRC) is increased in LT patients. We assessed course of disease in patients with de novo CRC after LT with focus of IS and impact on survival in a retrospective, single-center study. Materials and Methods: All patients diagnosed with CRC after LT between 1988 and 2019 were included. The management of IS regimen following diagnosis and the oncological treatment approach were analyzed: Kaplan−Meier analysis as well as univariate and multivariate analysis were performed. Results: A total of 33 out of 2744 patients were diagnosed with CRC after LT. Two groups were identified: patients with restrictive IS management undergoing dose reduction (RIM group, n = 20) and those with unaltered regimen (maintenance group, n = 13). The groups did not differ in clinical and oncological characteristics. Statistically significant improved survival was found in Kaplan−Meier analysis for patients in the RIM group with 83.46 (8.4−193.1) months in RIM and 24.8 (0.5−298.9) months in the maintenance group (log rank = 0.02) and showed a trend in multivariate cox regression (p = 0.054, HR = 14.3, CI = 0.96−213.67). Conclusions: Immunosuppressive therapy should be reduced further in patients suffering from CRC after LT in an individualized manner to enable optimal oncological therapy and enable improved survival.

Comparison of an Inside Stent and a Fully Covered Self-Expandable Metallic Stent as Preoperative Biliary Drainage for Patients with Resectable Perihilar Cholangiocarcinoma

Background

There is a need for a more tolerable preoperative biliary drainage (PBD) method for perihilar cholangiocarcinoma (PHCC). In recent years, inside stents (ISs) have attracted attention as a less suffering PBD method. Few studies have compared IS with a fully covered self-expandable metallic stent (FCSEMS) as PBD for resectable PHCC. The aim of this study is to compare them.

Methods

This study involved 86 consecutive patients (IS: 51; FCSEMS: 35). The recurrent biliary obstruction (RBO) rate until undergoing surgery or being diagnosed as unresectable, time to RBO, factors related to RBO, incidence of adverse events related to endoscopic retrograde cholangiography, and postoperative complications associated with each stent were evaluated retrospectively.

Results

There was no significant difference between the two groups in the incidence of adverse events after stent insertion. After propensity score matching, the mean (SD) time to RBO was 37.9 (30.2) days in the IS group and 45.1 (35.1) days in the FCSEMS group, with no significant difference (P=0.912, log-rank test). A total of 7/51 patients in the IS group and 3/35 patients in the FCSEMS group developed RBO. The only risk factor for RBO was bile duct obstruction of the future excisional liver lobe(s) due to stenting (HR 29.8, P=0.008) in the FCSEMS group, but risk factors could not be indicated in the IS group. There was no significant difference in the incidence of bile leakage or liver failure. In contrast, pancreatic fistula was significantly more common in the FCSEMS group (13/23 patients) than in the IS group (3/28 patients) (P < 0.001), especially in patients who did not undergo pancreatectomy (P=0.001).

Conclusions

As PBD, both IS and FCSEMS achieved low RBO rates. Compared with FCSEMS, IS shows no difference in RBO rate, is associated with fewer postoperative complications, and is considered an appropriate means of PBD for resectable PHCC. This trail is registered with UMIN000025631.

Interactions between human microbiome, liver diseases, and immunosuppression after liver transplant

In liver transplant patients, solid tumors and post-transplant lymphoproliferative disorders have emerged as significant long-term mortality causes. In addition, it is assumed that de novo malignancy after liver transplantation (LT) is the second-leading cause of death after cardiovascular complications. Well-established risk factors for post-transplant lymphoproliferative disorders and solid tumors are calcineurin inhibitors, tacrolimus, and cyclosporine, the cornerstones of all immunosuppressive therapies used after LT. The loss of immunocompetence facilitated by the host immune system due to prolonged immunosuppressive therapy leads to cancer development, including LT patients. Furthermore, various mechanisms such as bacterial dysbiosis, activation through microbe-associated molecular patterns, leaky gut, and bacterial metabolites can drive cancer-promoting liver inflammation, fibrosis, and genotoxicity. Therefore, changes in human microbiota composition may contribute further to de novo carcinogenesis associated with the severe immunosuppression after LT.