Researchers Validate Novel Prediction Index for HCC After Liver Transplant

Neil Mehta, MD

A new system for gauging the probability for hepatocellular carcinoma (HCC) recurrence following liver transplant (LT) surgery has proved successful, according to Neil Mehta, MD, a gastroenterologist and transplant hepatologist who presented the study results November 13, 2016 at the American Association for the Study of Liver Diseases annual Liver Meeting.

The study, based on historical data from UNOS, which coordinates United States transplant activities, evaluated the viability of the Risk Estimation of Tumor Recurrence After Transplant (RETREAT) system.

Results showed that the lower the RETREAT score, the better the chances of post LT survival were 3 years after LT, which confirmed the utility of the scoring system.

Tumor recurrence after LT is the most common cause of death for HCC patients. For the past 20 years, Milan criteria (1 lesion of < 5 cm, 2-3 lesions of < 3 cm) have been the standard for choosing ideal HCC LT candidates. During that period, HCC recurrence with LT has been 10% to 15% with a median survival of approximately 1 year after HCC recurrence. In search of ways to decrease tumor recurrence and better identify patients who may benefit from adjuvant therapies, researchers tested the RETREAT system.

RETREAT incorporates 3 variables that independently predict HCC recurrence: microvascular invasion (MVI), alpha-fetoprotein (AFP) at LT, and the sum of the largest viable tumor diameter and number of viable tumors on the explant.

A total of 4,218 patients were considered for study, based on UNOS data. The final cohort totaled 3,392. Patients were excluded based on unavailable explant tumor burden (n=22), no AFP within 90 days of LT (n=769), and no HCC on explant without local-regional therapy (LRT) (n=35).

Harrell’s C-index and the net reclassification index (NRI) were used to evaluate the performance of RETREAT in predicting HCC recurrence.

Median age of participants was 60, 77% were male, and 91% received LRT before LT. Median time from listing to LT was 5 months. Median AFP at LT was 9. In the explant, 13% had MVI, 30% had no viable tumor, and 15% were beyond Milan criteria. The RETREAT score was 0-1 in 56% and >4 in 12%. Researchers concluded that the post-LT survival at 3 years decreased with an increasing RETREAT score: 91% for a score of 0; 80% for a score of 3; and 58% for a score >5. However, time from recurrence to death was similar across scores. The study found that 151 patients or 4.5% developed HCC recurrence at a median of 11 months post-LT.

They concluded that “RETREAT outperformed Milan criteria in predicting post LT HCC recurrence and may have important implications for post LT HCC surveillance strategies and to help identify patients who would derive the most benefit from future adjuvant therapies.”

The larger study was based on a smaller study of roughly 1000 patients which was used to develop the RETREAT system.

Mehta N, Dodge J, Sarkar M, Roberts J, Yao F. Validation of the RETREAT score, a novel prediction index for HCC recurrence after liver transplant using the UNOS database [AASLD abstract 6].

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