Background: Recent changes in HCC exception point policy aims to equalize wait list outcomes between HCC and non-HCC patients, but remains dissociated from tumor biology. We determined the 90-day drop out risk (90DR) of wait listed patients based on total tumor size (TTS) and built an open source simulation model of liver allocation (MY-ATLAS) to predict pre and post-transplant outcomes of a policy based on TTS.

Methods: Non-HCC (39,239) 90DR by lab MELD was mapped by logistic regression model. Similarly, HCC (25,830) 90DR by TTS <2, 2-4, 4-6, >6 cm (Milan criteria), or within UCSF criteria (outside Milan) was determined (all patients from SRTR SAF). Due to limitations of the commonly used LSAM (SRTR), we developed MY-ATLAS to evaluate outcomes of various exception point schemes.

Results: 90DR and corresponding MELD scores for each tumor category are shown in Table 1. Table 2 compares the total transplant benefit (years), percent transplant, and percent dropout for the exception point scheme instituted 2005, the current policy instituted 2015, exception points based on TTS (Table 1), and TTS + lab MELD. TTS+lab MELD yields the greatest transplant benefit, but has a slightly higher gap in txp % and dropout % than the 2015 or TTS alone policies. Analysis of HR death on the wait list and post-transplant showed that patients with HCC beyond Milan and within UCSF criteria had lower risk of death both pre and post-transplant than those within Milan but TTS > 6 cm.

Conclusion: We propose exception points and upgrades based on TTS rather than uniform points and automatic upgrades for all patients meeting Milan criteria. MY-ATLAS results suggest that such a policy could increase overall transplant benefit without significantly disturbing the balance between HCC and non-HCC cohorts. Moreover, MY-ATLAS can be easily modified by other researchers to study other changes in organ allocation and distribution.

CITATION INFORMATION: Yeh H, Akan M, Leung N.-H, Markmann J, Tayur S. Proposal for HCC Exception Points to Match Drop Out Risk. Am J Transplant. 2017;17 (suppl 3).

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