Liver transplantation for unresectable colorectal liver metastasis

Hepatobiliary Surg Nutr 2013;2(3):162-164 www.thehbsn. org The rapid progression in the development of liver transplantation during the last decade is largely attributed by the standardization of operative techniques (1,2) and advances in the pharmacokinetics of immunosuppressive therapy (3). Such improvements in the perioperative management have rendered liver transplantation a safer operation and in turn translated into better long-term survival (4,5). As such, the indication for liver transplantation has been expanded to include malignant liver tumor other than liver cirrhosis. Since the proposal of Milan criteria by Professor Mazzaferro in the late 1990s, liver transplantation has been universally adopted as the curative treatment for early staged hepatocellular carcinoma (HCC) in patients with liver cirrhosis (6). As a result, the 5-year overall survival rate has reached up to 70% in various series (7,8). More importantly, the introduction of Milan criteria has since revolutionized the indications for transplantation and the allocation policy for cadaveric organs. As success was witnessed in the surgical management of HCC with transplantation, the indication has been extended to include other form of solid liver malignancies such as neuroendocrine liver metastasis and cholangiocarcinoma in the hope that similar survival outcome could be attained. Neuroendocrine tumor is a highly vascular tumor with variable aggressiveness. It embraces a wide spectrum of tumor that arises from the neuroendocrine cells in the gastrointestinal tract and pancreas. For untreated neuroendocrine liver metastasis, the 5-year survival is approximately 30-40%. With transplantation, the survival for patients with unresectable neuroendocrine liver metastasis has drastically improved to 80% at 5 years in recent study (9). On the other hand, transplantation in patients with cholangiocarcinoma had a longer history of development that could be dated back to the early 1990s. At that time, the outcome was rather disappointing with a 5-year survival rate of merely 5-10% (10). With the advancement of chemoradiation in recent years, the survival outcome has been drastically improved. Using the Mayo protocol i.e., neoadjuvant radiotherapy, chemosensitization with 5-FU and oral capecitabine for patients with early cholangiocarcinoma <3 cm and concomitant primary sclerosing cholangitis, both the 3and 5-year survival rates are reported to be approximately 80% respectively (11). Despite the improved oncological outcome of liver transplantation to non-HCC liver tumor, the experience so far is limited to certain centers only. The lack of enthusiasm of transplant centers to embark on such a program is partly related to the scarcity of donor organ that prohibits a liberal allocation other than to those with end-stage liver diseases or early staged unresectable HCC. Second, the uncertain malignant potential of these tumors and the variable oncological outcomes after transplantation are major concerns for adoption of such treatment strategy. It is noteworthy to highlight that since this group of patients, by enlarge does not have liver failure or complications related to cirrhosis, the primary endpoint that defines the efficacy of transplantation in this setting should be the recurrence-free survival and overall survival. A high recurrence rate after transplantation could potentially pose another challenge to the clinicians. From our experience in HCC, recurrence after liver transplantation is often extrahepatic (12) and the lack of effective treatment options for extrahepatic recurrences is another important reason that limits the widespread application of transplantation to other types of liver malignancy. Perspective