The development of de novo hepatocellular carcinoma in patients on a liver transplant list: frequency, size, and assessment of current screening methods.

Chronic end stage liver disease is the most frequent indication for liver transplantation. Individuals with end stage cirrhosis, and therefore individuals on liver transplant lists, are at increased risk of developing a hepatic cancer. Those individuals on liver transplant lists also may represent the best group available for evaluating the current methods for screening and surveillance for the development of hepatic cancer as an examination of the explant liver provides a gold standard for tumor assessment. Assuming that only tumor free individuals were screened at the onset of this study, the data obtained enables one to determine the frequency of new hepatic cancers since listing and evaluate the positive and negative predictive values of each assessment method over the surveillance interval. All patients listed for liver transplantation with end stage chronic liver disease, who did not have a hepatoma at the time of transplant listing, were followed and assessed for the development of a hepatic cancer while on the waiting list. The screening techniques utilized included quarterly alpha fetoprotein (alpha FP) determinations and ultrasound (US) studies as well as semi-annual triple phase computed tomography (CT) scans of the liver. alpha FP failed to identify any cases of de novo hepatic cancer in patients waiting for a liver transplant. In contrast, US and especially CT scanning with intravenous contrast identified new hepatic masses. The later method, which identified early enhancing mass lesions, was the more valuable method at identifying masses that subsequently were shown by pathologic examination of the explant liver to be hepatic cancers. However, only 14 of 20 individuals found to have a de novo tumor were identified by this method. Once identified however, the treatments utilized for hepatic tumor ablation while waiting for a transplant appear to be effective with a mean of 57.8+/-8.3% necrosis of the treated masses being identified at the time of explant examination. In conclusion these data suggest that: 1. The development of a hepatocellular carcinoma (HCC) in an individual on a transplant list is not rare and occurs in as many as 20% of cases; 2. The most effective method for the detection of de novo HCC appears to be semi-annual triphasic CT scan with the identification of a new early enhancing lesion; and 3. Once recognized, the presence of the tumor enables the individual to move up on the waiting list as result of the additional model endstage liver disease (MELD) points allowed for individuals with HCCs.