Biases in the reporting of hepatocellular carcinoma tumor sizes on the liver transplant waiting list.

We investigated the possibility that patients with hepatocellular carcinoma (HCC) listed for liver transplant with tumors just outside stage T2 size criteria may be inaccurately reported as just meeting the tumor size criteria for transplant. The United Network for Organ Sharing/Standard Transplant Analysis and Research database identified 12,958 patients listed for liver transplants with HCC exception points from 2006 to 2013, 9,168 of whom were listed with one tumor. A logistic power peak function was fitted to the single-tumor size histogram, with the fitted values representing unbiased expected values. The difference between the observed and expected tumor counts for 2.0 cm and 5.0 cm was 238 (22%) and 66 (57%), respectively. This suggests that up to 304 (3.0%) patients with tumors outside of transplant criteria had their measurements recorded at the margins of eligibility. A risk-adjusted Poisson model evaluated the ratio of observed to expected HCC recurrence by tumor size. There were 435 HCC recurrences among 6,049 transplants. Only 2.0-cm tumors had observed to expected recurrence differing from 1 (ratio 0.73, 95% confidence interval 0.57-0.94), indicating a 27% lower than expected rate of recurrence.
CONCLUSION: Higher than expected observed tumor counts at the lower transplant criteria margin were corroborated by lower than expected HCC recurrence, suggesting that tumor sizes at the margins of HCC transplant criteria may be subject to inaccurate reporting. (Hepatology 2017;66:1144-1150).