Liver Function Abnormalities and Hepatic Enzyme Profiles in Patients with Nasopharyngeal Carcinoma: A Review

Abstract

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy associated with Epstein-Barr virus which is characterised by a high degree of geographic clustering in Southern China, Southeast Asia and some areas of North Africa and the Middle East. The clinical picture is dominated by the nasopharynx and its draining lymphatics but the liver is recurrently involved in the natural history and therapy of the disease and aberrant hepatic biochemistry is seen significantly more frequently than is typically acknowledged. This study brings together the scattered data of liver function impairments and hepatic enzyme profile in NPC and attempts to interpret the reasons for their occurrence and the significance. We discuss four major pathways in which the liver is involved: synchronous or metachronous hepatic metastasis, reactivation of chronic hepatitis B virus in the setting of cytotoxic therapy, drug-induced hepatotoxicity from platinum-based regimens and, more recently, immune-related hepatitis due to PD-1 blockade. We then review the literature on the use of individual liver-derived markers as prognostic tools, with particular emphasis on lactate dehydrogenase, gamma-glutamyl transferase, the aspartate-to-alanine aminotransferase (De Ritis) ratio, alkaline phosphatase and composite indices such as the albumin-to-alkaline-phosphatase ratio. A common feature across the research is that inexpensive, frequently available biochemical assays have significant predictive information that is, at least in part, independent of TNM stage. We end with practical implications for baseline screening, antiviral prophylaxis and on-treatment surveillance and flag the methodological weaknesses of retrospective design, inconsistent cut-offs and limited geographic diversity that still limit confident clinical translation.