Background: Tacrolimus is a key immunosuppressant after liver transplantation.Although guideline-recommended trough levels are 4–10 ng/mL, concerns about nephrotoxicity, metabolic complications, and malignancies have led to interest in minimizing tacrolimus use. However, the effects of lower tacrolimus levels on graft rejection and hepatocellular carcinoma (HCC) recurrence remain unclear. Methods: We conducted a single-center, retrospective study of adult patients (≥19 years) who underwent living donor liver transplantation between January 2000 and December 2021. Patients were divided into low tacrolimus (FK) (<6 ng/mL) and high FK (≥6 ng/mL) groups based on tacrolimus levels measured 1–2 years post-transplantation. We analyzed overall survival, biopsy-proven rejection-free survival, and HCC recurrence-free survival in relevant subgroups. Cox proportional hazards regression identified predictors of mortality, rejection, and HCC recurrence. Results: Among 1,117 recipients, 941 were in the low FK group and 176 in the high FK group. Landmark analysis showed significantly better 10-year overall survival in the low FK group (82.8% vs. 68.8%, p=0.016), while rejection-free survival did not differ significantly beyond 2 years (p=0.098), despite early separation favoring the low FK group (p<0.001). Higher tacrolimus levels independently predicted increased mortality (hazard ratio [HR]=1.98, 95% confidence interval [CI] 1.35–2.89; p<0.001) and rejection (HR=2.20, 95% CI 1.48–3.27; p<0.001). Among 614 HCC patients, landmark analysis revealed no significant difference in recurrence-free survival (77.7% vs. 81.2%, p=0.288) or overall survival (77.3% vs. 65.8%, p=0.215), and FK levels were not independently associated with either outcome. Conclusion Maintaining tacrolimus levels below 6 ng/mL was associated with better survival and rejection outcomes without increasing HCC recurrence, suggesting dose minimization may be feasible in selected patients.

In liver transplantation, the primary concern is to ensure an adequate future liver remnant (FLR) volume for the donor, while selecting a graft of sufficient size for the recipient. The living donor–resection and partial liver segment 2−3 transplantation with delayed total hepatectomy (LD−RAPID) procedure offers a potential solution to expand the donor pool for living donor liver transplantation (LDLT).We report the first case involving a cirrhotic patient with autoimmune hepatitis and hepatocellular carcinoma, who underwent left lobe LDLT using the LD−RAPID procedure. The living liver donor (LLD) underwent a laparoscopic left hepatectomy, including middle hepatic vein. The resection on the recipient side was an extended left hepatectomy, including the middle hepatic vein orifice and caudate lobe. At postoperative day 7, a computed tomography scan showed hypertrophy of the left graft from 320 g to 465 mL (i.e., a 45.3% increase in graft volume body weight ratio from 0.60% to 0.77%). After a 7-day interval, the diseased right lobe was removed in the second stage surgery. The LD−RAPID procedure using left lobe graft allows for the use of a small liver graft or small FLR volume in LLD in LDLT, which expands the donor pool to minimize the risk to LLD by enabling the donation of a smaller liver portion.

Colorectal cancer (CRC) poses a significant global health challenge, particularly with patients often experiencing liver metastases. Surgical resection remains the standard treatment; however, many patients face ineligibility due to disease status, contributing to poor prognoses. Liver transplantation (LT) is a viable alternative for select patients with advanced disease. This case report details the clinical outcomes of two CRC patients with multiple liver metastases who successfully underwent living donor LT (LDLT). Both individuals had intricate medical histories and pre-existing liver issues. Patient 1, a 58-year-old male, received extensive pre-transplant interventions, including multiple radiofrequency ablations and pulmonary resections. Patient 2, a 50-year-old male, had cirrhosis alongside colorectal cancer with liver metastases and completed chemotherapy. The cases illustrate LDLT's viability and potential advantages for complex CRC cases with liver metastases. The patients’ intricate medical backgrounds necessitate thorough pre-transplant evaluations and vigilant post-transplant supervision. Moreover, these cases highlight the critical nature of ongoing follow-up for evaluating long-term survival and recognizing possible complications.