Research ArticleValidation of the “Metroticket” predictor in a cohort of patients transplanted for predominantly HBV-related hepatocellular carcinoma
Introduction
Hepatocellular carcinoma (HCC) is the 5th most common cancer globally [1] and has the fastest growing cancer mortality, related to the current epidemic of Hepatitis C [2]. It is the leading cause of mortality in patients with cirrhosis [3]. Liver transplant (LT) addresses the cancer, its potential multifocal nature, as well as the underlying liver cirrhosis [4]. The role of LT has been firmly established since the “Milan Criteria” were generated in 1996 and demonstrated good long term survival and low recurrence rates in patients with either one tumour under 5 cm or up to three tumours under 3 cm (actuarial survival 75% and recurrence-free survival 83% after 4 years) [5].
Selection criteria for LT have been gradually expanded over subsequent years in an effort to include more patients who could potentially benefit, yet still preserve an acceptable survival. Yao et al. modestly expanded these parameters with the “UCSF expanded criteria” [4], which were subsequently validated in a prospective cohort based on pre-operative imaging [6]. Mazzaferro et al. have recently developed the “Up to seven” criteria based on a large multicentre cohort of 1112 patients who exceeded the Milan criteria – 238 met the up to seven criteria and had an acceptable 5 year survival of 71.2% [7].
In the same study, the authors developed a novel prognostic model called the “Metroticket”, based on a continuum of size and number, whereby each patient is assigned an individual prognosis for 3 and 5 year survival. This provides a paradigm shift from a dichotomous to continuous prognostic stratification for patients with HCC being assessed for LT.
The Metroticket model has not been externally validated on an independent series of patients undergoing LT for HCC. The aim of this study is to test the prognostic accuracy of the Metroticket in an independent cohort of patients. In addition, whilst the original European study cohort included predominately HCC cases secondary to alcoholic liver disease and hepatitis C-related, this current Asia–Pacific study includes predominately hepatitis B-related HCC.
Section snippets
Patients
This was a retrospective cohort study of all patients listed for liver transplantation with known HCC (including those not transplanted) at the New Zealand Liver Transplant Unit (NZLTU) between January 1998 and November 2009. A prospectively maintained database of all patients listed and transplanted was supplemented by medical records, laboratory, radiological, and pathological data.
Baseline demographic data (age, gender, and ethnicity), aetiology of underlying liver disease, and HCC-related
Results
Between 1st January, 1998 and 30th November, 2009, 95 patients were listed for LT for HCC, of whom 82 were transplanted. There was no peri-operative mortality in patients transplanted with HCC. Thirteen patients were delisted prior to transplantation; 10 for tumour progression, 1 for sepsis and 2 who received alternative treatments (resection and radio-frequency ablation). Twenty-nine patients received 40 TACE treatments whilst on the waiting list.
Baseline demographics for all patients are
Discussion
Liver transplantation is a highly effective treatment for HCC, however, there is continual pressure on limited donor resources and debate in the transplant community about what should be considered an acceptable minimum 5-year post-transplant survival probability [9], [10]. As different selection criteria have been proposed, their boundaries have continually been challenged. For example, the recent “Up to seven” criteria allow for a total tumour diameter of 12 cm compared to 9 cm for the Milan
Conflict of interest
The authors who have taken part in this study declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.
Acknowledgements
Andrew Holden, Radiologist; Mee-Ling Yeong, Pathologist; Kai Chau, Pathologist; and Lindsay Plank, Biostatistician.
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