Introduction: Perihilar cholangiocarcinoma (phCCA) is a highly aggressive malignancy and treatment options for this devastating disease have been limited. Resection is the standard of care, however, even when resection is possible, 5-year survival is only 20–40% in the world. And unresectable phCCA have a poor prognosis with a 5-year survival rate nearly zero. Liver transplantation (LT) in combination with neoadjuvant chemoradiation therapy has become the treatment of choice for unresectable phCCA. In 2018, we launched a prospective study to evaluate the feasibility and efficacy of living donor LT (LDLT) for unresectable phCCA.
Patients: Ten patients were enrolled in this prospective study at our single center between 2018 and 2023. One patient eventually underwent hepatic resection after portal vein embolization and another patient refused LDLT for a financial reason. Eight patients proceeded to chemotherapy, with 2 patients excluded during chemotherapy due to tumor progression in one and post-endoscopic retrograde cholangiopancreatography pancreatitis in the other. Six patients received radiation therapy after completing chemotherapy. After radiation therapy, one patient had a positive lymph node biopsy and dropped out of the protocol. Finally, the present study analyzed 5 cases of unresectable phCCA that underwent LDLT.  
Result: The median follow-up period was 21.4 months. The overall survival rate for all 5 patients with unresectable phCCA was 100% at 1 year. One patient had recurrence with multiple bone metastases 10 months after LDLT. Several notable post-operative complications were observed. Notably, hepatic artery thrombosis (HAT) and delayed gastric emptying (DGE) occurred in two and three cases, respectively. In one case, HAT developed on postoperative day 4, necessitating re-anastomosis. In the other patient, a CT at 3 months after LDLT showed occlusion of the hepatic artery, following a subclinical course. DGE developed about postoperative one week and persisted for about 3 months in the longest case. The histological type was tubular adenocarcinoma in all patients. Histological efficacy of preoperative treatment was Grade 2 and Grade IIb of Evans classification in all five patients. Portal vein invasion was present in one case. Surgical margins were negative and lymph nodes metastases were absent in all the patients.
Discussion: In this study, we showed favorable results of our prospective study of LDLT for unresectable phCCA. All five patients who underwent LDLT in this study are alive, and four are free of recurrence. However, the high frequency of several characteristic post operative complications, HAT and DGE, is a matter of concern. In particular, HAT appears to be associated with preoperative radiotherapy. Therefore, this procedure should be performed in experienced centers, with avoidance of using irradiated arteries.
Conclusion: LDLT is feasible and may be the last bastion for unresectable phCCA.