Systematic review: the prognostic role of alpha-fetoprotein following liver transplantation for hepatocellular carcinoma

Background Liver transplantation (LT) offers a possible cure for carefully selected patients with hepatocellular carcinoma (HCC). Studies report that preoperative alpha-fetoprotein (AFP) is a prognostic indicator that can predict survival and recurrence in these patients. Aim To undertake a systematic review of available literature on preoperative AFP as a predictor of survival and recurrence following LT for HCC. Methods A literature search was performed using Medline, Embase, Cochrane Library, CINAHL and Google scholar databases to identify studies reporting AFP as a prognostic marker in LT for HCC. Primary outcomes of interest were overall survival and recurrence. Secondary outcomes were correlation of pre-LT AFP with vascular invasion and grade of tumour differentiation. Results A total of 13 studies met the inclusion criteria (12 159 patients). The majority were male (9603, 78.9%). All were observational studies and only one prospective. Methodological quality was rated as poor for all studies, with selection and observer bias apparent for most cohorts. Reported survival rates and recurrence rates varied widely between the studies although overall demonstrated better outcomes for those with lower (<1000 ng/mL) pre-LT AFP levels. Similarly, rates of vascular invasion and poor tumour differentiation were higher in those with high pre-LT AFP levels. Conclusions A quantity of AFP >1000 ng/mL is associated with poorer outcomes from liver transplantation for hepatocellular carcinoma. The quality of studies was generally poor and precluded valid statistical meta-analysis. There is a need to improve the performance and reporting of primary prognostic studies to facilitate high quality systematic review and meta-analysis.