Vol. 220, No. 6, June 2015
survival, and have low rates of HCC recurrence. Mandatory fixed wait times for HCC candidates across regional boundaries may allow for improved liver distribution to the nonHCC candidates residing in regions of need. Although this may come at the cost of increased resource use for waitlist maintenance of the HCC candidate, this needs to be balanced with the potential for more equitable distribution of organs and improved access for the non-HCC candidates, who lack the benefit of time. Taken into consideration, further studies focusing on achieving equity of organ distribution in a cost-conscious health care system are needed in order to develop an improved liver allocation system for patients with and without HCC. Author Contributions Study conception and design: Patel, Kohn, Kratz, Markmann, Vagefi Acquisition of data: Patel, Kohn, Kratz, Shah, Vagefi Analysis and interpretation of data: Patel, Kohn, Kratz, Shah, Markmann, Vagefi Drafting of manuscript: Patel, Kohn, Kratz, Markmann, Vagefi Critical revision: Patel, Kohn, Kratz, Shah, Markmann, Vagefi REFERENCES 1. Wiesner RH, Freeman RB, Mulligan DC. Liver transplantation for hepatocellular cancer: the impact of the MELD allocation policy. Gastroenterology 2004;127:S261eS267. 2. Roayaie K, Feng S. Allocation policy for hepatocellular carcinoma in the MELD era: room for improvement? Liver Transplantation 2007;13:S36eS43. 3. Massie AB, Caffo B, Gentry SE, et al. MELD exceptions and rates of waiting list outcomes. Am J Transplant 2011;11:2362e2371. 4. Pomfret EA, Washburn K, Wald C, et al. Report of a national conference on liver allocation in patients with hepatocellular carcinoma in the United States. Liver Transplantation 2010;16:262e278. 5. Washburn K, Edwards E, Harper A, Freeman R. Hepatocellular carcinoma patients are advantaged in the current liver transplant allocation system. Am J Transplant 2010;10:1643e1648. 6. Goldberg D, French B, Abt P, et al. Increasing disparity in waitlist mortality rates with increased model for end-stage liver disease scores for candidates with hepatocellular carcinoma versus candidates without hepatocellular carcinoma. Liver Transplantation 2012;18:434e443. 7. Freeman RB Jr, Steffick DE, Guidinger MK, et al. Liver and intestine transplantation in the United States, 1997-2006. Am J Transplant 2008;8:958e976. 8. Yeh H, Smoot E, Schoenfeld DA, Markmann JF. Geographic inequity in access to livers for transplantation. Transplantation 2011;91:479e486. 9. Kohn R, Kratz JR, Markmann JF, Vagefi PA. The migrated liver transplantation candidate: insight into geographic disparities in liver distribution. J Am Coll Surg 2014;218:1113e1118.
Freeman
Invited Commentary
1007
10. Vagefi PA, Feng S, Dodge JL, et al. Multiple listings as a reflection of geographic disparity in liver transplantation. J Am Coll Surg 2014;219:496e504. 11. Ferlay J SI, Ervik M, Dikshit R, et al. GLOBOCAN 2012 v1.0, Cancer incidence and mortality worldwide: IARC CancerBase No. 11. Available at: http://globocan.iarc.fr, Accesed May 18, 2014. 12. Vivarelli M, Montalti R, Risaliti A. Multimodal treatment of hepatocellular carcinoma on cirrhosis: an update. World J Gastroenterol 2013;19:7316e7326. 13. Patel MS, Vagefi PA. Commentary on: Mesohepatectomy for centrally located large hepatocellular carcinoma: Indications, techniques, and outcomes. Surgery 2014;156: 1188e1189. 14. Nathan H, Segev DL, Mayo SC, et al. National trends in surgical procedures for hepatocellular carcinoma: 1998-2008. Cancer 2012;118:1838e1844. 15. Schlansky B, Chen Y, Scott DL, et al. Waiting time predicts survival after liver transplantation for hepatocellular carcinoma: A cohort study in the UNOS registry. Liver Transplantation 2014;20:1045e1056. 16. Chao SD, Roberts JP, Farr M, Yao FY. Short waitlist time does not adversely impact outcome following liver transplantation for hepatocellular carcinoma. Am J Transplant 2007;7: 1594e1600. 17. Halazun KJ, Patzer RE, Rana AA, et al. Standing the test of time: Outcomes of a decade of prioritizing patients with HCC, results of the UNOS natural geographic experiment. Hepatology 2014;60:1957e1962. 18. Samoylova ML, Dodge JL, Yao FY, Roberts JP. Time to transplantation as a predictor of hepatocellular carcinoma recurrence after liver transplantation. Liver Transplantation 2014; 20:937e944. 19. Gentry SE, Massie AB, Cheek SW, et al. Addressing geographic disparities in liver transplantation through redistricting. Am J Transplant 2013;13:2052e2058. 20. Axelrod DA, Dzebisashvili N, Lentine K, et al. Assessing variation in the costs of care among patients awaiting liver transplantation. Am J Transplant 2014;14:70e78. 21. McAdam-Marx C, McGarry LJ, Hane CA, et al. All-cause and incremental per patient per year cost associated with chronic hepatitis C virus and associated liver complications in the United States: a managed care perspective. J Managed Care Pharmacy 2011;17:531e546. 22. OPTN/UNOS Liver and Intestinal Organ Transplantation Committee Report to the Board of Directors. Richmond, Virginia June 23-24, 2014. 23. Lai JC, Feng S, Roberts JP. An examination of liver offers to candidates on the liver transplant wait-list. Gastroenterology 2012;143:1261e1265.
Invited Commentary Richard B Freeman Jr, Lebanon, NH
MD, FACS
The team from Massachusetts General Hospital Liver Transplant Program has provided an interesting
1008
Freeman
Invited Commentary
retrospective review of their experience with their patients on the liver transplant waiting list. These investigators compare patients assigned increased priority according to the United Network for Organ Sharing/Organ Procurement and Transplantation Network policy for hepatocellular cancer (HCC) diagnoses with those who are prioritized according to standard criteria in an effort to illustrate effects of the liver allocation policy. The current prioritization scheme was developed more than 13 years ago and was driven by a mortality risk calculation to assign priority to waiting candidates.1 It was recognized back then that, in a risk-of-death driven system, patients with HCC would be disadvantaged because their tumors would likely progress faster than their underlying liver disease. Consequently, policymakers anticipated that patients with HCC would “drop off” of the waiting list due to progression of their cancer more rapidly than they would reach a high mortality risk. For this reason, the policymakers assigned an increased priority for the HCC patients to try and make the drop-out rate for patients with HCC relatively similar to that for patients with non-HCC diagnoses. The point of the HCC exception rule is that policymakers recognized that HCC candidates would not have a high mortality rate on the waiting list and a mortality driven allocation scheme, such as the one that drives allocation of livers to non-HCC candidates, would, in a large number of cases, prevent HCC candidates from getting enough priority to receive a liver offer before their tumor progressed to an unfavorable stage. This policy was developed well before the significant improvements in loco-regional ablative treatments were developed and without good knowledge about the rate of progression for early stage HCC. More recent data have shown that the rate of dropout for HCC patients on the waiting list is actually much lower than originally thought, and for single tumors less than 2 cm, only about 10% will progress beyond Milan criteria within a year, particularly if the tumor is responsive to ablative treatments.2 These data, in combination with comparisons of transplantation rates for HCC and non-HCC patients using the Scientific Registry of Transplant Recipients, competing risks,3 and propensity matching,4 showing that HCC patients have higher transplant rates and lower dropout rates overall, suggest that the priority given to HCC patients under the current system may be too high. Patel and colleagues from the Massachusetts General Hospital retrospectively examined their single-center experience with their waiting list and transplantation rates comparing patients with HCC exception priority with candidates who did not qualify for HCC exception. They found in their patients that the death rate on the
J Am Coll Surg
waiting list was much lower and the transplantation rate was much higher for the candidates with HCC compared with non-HCC patients, and the overall posttransplantation survival was similar at 1 and 5 years between the 2 groups. These results are very consistent with the reports using larger national databases cited above and lend further weight to the suggestion that priority for HCC patients under the current system is too high. It should be noted that the fact that the HCC cohort in this study had a much lower waiting list mortality rate is not surprising because this illustrates precisely why the HCC exception policy was developed. In this case, the overall waiting list removal rate for death or deterioration was similar among the HCC (25.5%) and nonHCC (21.8%, p ¼ 0.32) candidates, suggesting that at least for the overall drop-off rate, the policy was achieving reasonable equity as desired. The authors raise another important point in stating, “In the current study, we have demonstrated that candidates with HCC can wait for relatively long periods while maintaining excellent overall survival post-transplant.” As with all health care, selection of treatments and their efficacy have the ability to affect the cost of care in various ways. These issues can be magnified in transplantation because the allocation process may introduce other incentives that can affect costs. The data here describing the increased number of pretransplantation admissions for the HCC candidates illustrates this fact. There is a strong incentive to slow or halt the progression of HCC while patients wait on the list so they do not progress beyond the tumor burden for which the policy will still confer increased priority. So this center, like many, are willing to readmit HCC patients multiple times for loco-regional treatments before transplantation in an effort to try to control tumor progression. It is interesting to note that it is possible that this process may also be selecting patients for better post-transplantation outcomes because there is evidence that HCC patients who are responsive to loco-regional treatments have lower recurrence rates after transplantation.5 There are a few caveats to interpreting this paper, however. The investigators excluded patients with cholangiocarcinoma and mixed tumors for unclear reasons and do not state how many of these were excluded and whether these received exception points. They also do not mention if patients with other diagnoses for which exception priority was granted were excluded from their analysis. If they were included, it is important to note to which group they were assigned because depending on the overall number, this could skew their results. In addition, most of the other studies looking at the question of HCC priority
Freeman
Vol. 220, No. 6, June 2015
on the waiting list have used a competing risks approach because there is more than 1 outcome possible for patients waiting on the list (transplantation, drop-off, and continued waiting). In the setting of analyzing waiting list dynamics, traditional dichotomous time-to-event statistics tend to overestimate rates because of censoring.6 Moreover, it should always be noted that the transplantation rate is influenced by the organ acceptance behavior on the part of the transplant center. Consequently, these data from this study should be interpreted carefully because the authors did not report the Donor Risk Index for the donors to HCC recipients compared with the Donor Risk Index for the donors to non-HCC recipients. It is possible that their organ acceptance behavior may have more readily accepted higher risk donors for the HCC candidates. If this were the case, the HCC patients would have been exposed to a wider donor pool, which might explain, at least partially, why they had a higher transplantation rate for this cohort in this study. Finally, these authors state, “In the current study, we have demonstrated that candidates with HCC can wait for relatively long periods while maintaining excellent overall survival post-transplant. Furthermore, the HCC candidate had significantly higher percentage of liver transplantation and fewer removals for death on the waitlist, when compared to their non-HCC counterparts. This finding suggests that a national reprioritization of available organs to non-HCC candidates whose survival may be compromised by prolonged waiting periods may be beneficial.” However, in some aspects, the data in this study illustrate that the HCC exception policy is working as designed because the overall removal rates and post-transplantation survival rates are similar for both groups. Nonetheless, it remains true that there are significant geographic differences in transplantation and drop-out rates across the country. However, this study did not provide data or address these differences. It may be overstating the data to suggest that this study has
Invited Commentary
1009
provided a “further assessment of the current system of liver allocation,” as the authors suggest in their introduction because their analysis is limited to only 1 center’s experience in a single region of the allocation and distribution system. In conclusion, these single center data to corroborate the larger national studies insofar as they find higher transplantation rates and lower death rates on the waiting list for HCC patients and post-transplantation outcomes that are similar to those for non-HCC patients. There is a large national effort to re-examine the liver distribution units in an effort to address some of the geographic difference to which these authors refer.7
REFERENCES 1. Freeman RB, Weisner RH, Harper A, et al. The New Liver Allocation System: moving towards evidence-based transplantation policy. Liver Transpl 2002;8:851e858. 2. Mehta N, Dodge JL, Goel A, et al. Identification of liver transplant candidates with hepatocellular carcinoma and a very low dropout risk: implications for the current organ allocation policy. Liver Transpl 2013;12:1343e1353. 3. Washburn K, Edwards E, Harper A, Freeman R. Hepatocellular carcinoma patients are advantaged in the current liver transplant allocation system. Am J Transplant 2010;7: 1643e1648. 4. Freeman RB, Edwards EB, Harper AM. Waiting list removal rates among patients with chronic and malignant liver diseases. Am J Transplant 2006;6:1416e1421. 5. Otto G, Herber S, Heise M, et al. Response to transarterial chemoembolization as a biological selection criterion for liver transplantation in hepatocellular carcinoma. Liver Transpl 2006;8: 1260e1267. 6. Kim WR, Therneau TM, Benson JT, et al. Deaths on the liver transplant waiting list: an analysis of competing risks. Hepatology 2006;2:345e351. 7. Redesigning Liver Distribution to Reduce Variation in Access to Liver Transplantation. A Concept Paper from the OPTN/UNOS Liver and Intestinal Organ Transplantation Committee. Available at: http://optn.transplant.hrsa.gov/ContentDocuments/Liver_ Concepts_2014.pdf. Accessed March 13, 2015.
survival, and have low rates of HCC recurrence. Mandatory fixed wait times for HCC candidates across regional boundaries may allow for improved liver distribution to the nonHCC candidates residing in regions of need. Although this may come at the cost of increased resource use for waitlist maintenance of the HCC candidate, this needs to be balanced with the potential for more equitable distribution of organs and improved access for the non-HCC candidates, who lack the benefit of time. Taken into consideration, further studies focusing on achieving equity of organ distribution in a cost-conscious health care system are needed in order to develop an improved liver allocation system for patients with and without HCC. Author Contributions Study conception and design: Patel, Kohn, Kratz, Markmann, Vagefi Acquisition of data: Patel, Kohn, Kratz, Shah, Vagefi Analysis and interpretation of data: Patel, Kohn, Kratz, Shah, Markmann, Vagefi Drafting of manuscript: Patel, Kohn, Kratz, Markmann, Vagefi Critical revision: Patel, Kohn, Kratz, Shah, Markmann, Vagefi REFERENCES 1. Wiesner RH, Freeman RB, Mulligan DC. Liver transplantation for hepatocellular cancer: the impact of the MELD allocation policy. Gastroenterology 2004;127:S261eS267. 2. Roayaie K, Feng S. Allocation policy for hepatocellular carcinoma in the MELD era: room for improvement? Liver Transplantation 2007;13:S36eS43. 3. Massie AB, Caffo B, Gentry SE, et al. MELD exceptions and rates of waiting list outcomes. Am J Transplant 2011;11:2362e2371. 4. Pomfret EA, Washburn K, Wald C, et al. Report of a national conference on liver allocation in patients with hepatocellular carcinoma in the United States. Liver Transplantation 2010;16:262e278. 5. Washburn K, Edwards E, Harper A, Freeman R. Hepatocellular carcinoma patients are advantaged in the current liver transplant allocation system. Am J Transplant 2010;10:1643e1648. 6. Goldberg D, French B, Abt P, et al. Increasing disparity in waitlist mortality rates with increased model for end-stage liver disease scores for candidates with hepatocellular carcinoma versus candidates without hepatocellular carcinoma. Liver Transplantation 2012;18:434e443. 7. Freeman RB Jr, Steffick DE, Guidinger MK, et al. Liver and intestine transplantation in the United States, 1997-2006. Am J Transplant 2008;8:958e976. 8. Yeh H, Smoot E, Schoenfeld DA, Markmann JF. Geographic inequity in access to livers for transplantation. Transplantation 2011;91:479e486. 9. Kohn R, Kratz JR, Markmann JF, Vagefi PA. The migrated liver transplantation candidate: insight into geographic disparities in liver distribution. J Am Coll Surg 2014;218:1113e1118.
Freeman
Invited Commentary
1007
10. Vagefi PA, Feng S, Dodge JL, et al. Multiple listings as a reflection of geographic disparity in liver transplantation. J Am Coll Surg 2014;219:496e504. 11. Ferlay J SI, Ervik M, Dikshit R, et al. GLOBOCAN 2012 v1.0, Cancer incidence and mortality worldwide: IARC CancerBase No. 11. Available at: http://globocan.iarc.fr, Accesed May 18, 2014. 12. Vivarelli M, Montalti R, Risaliti A. Multimodal treatment of hepatocellular carcinoma on cirrhosis: an update. World J Gastroenterol 2013;19:7316e7326. 13. Patel MS, Vagefi PA. Commentary on: Mesohepatectomy for centrally located large hepatocellular carcinoma: Indications, techniques, and outcomes. Surgery 2014;156: 1188e1189. 14. Nathan H, Segev DL, Mayo SC, et al. National trends in surgical procedures for hepatocellular carcinoma: 1998-2008. Cancer 2012;118:1838e1844. 15. Schlansky B, Chen Y, Scott DL, et al. Waiting time predicts survival after liver transplantation for hepatocellular carcinoma: A cohort study in the UNOS registry. Liver Transplantation 2014;20:1045e1056. 16. Chao SD, Roberts JP, Farr M, Yao FY. Short waitlist time does not adversely impact outcome following liver transplantation for hepatocellular carcinoma. Am J Transplant 2007;7: 1594e1600. 17. Halazun KJ, Patzer RE, Rana AA, et al. Standing the test of time: Outcomes of a decade of prioritizing patients with HCC, results of the UNOS natural geographic experiment. Hepatology 2014;60:1957e1962. 18. Samoylova ML, Dodge JL, Yao FY, Roberts JP. Time to transplantation as a predictor of hepatocellular carcinoma recurrence after liver transplantation. Liver Transplantation 2014; 20:937e944. 19. Gentry SE, Massie AB, Cheek SW, et al. Addressing geographic disparities in liver transplantation through redistricting. Am J Transplant 2013;13:2052e2058. 20. Axelrod DA, Dzebisashvili N, Lentine K, et al. Assessing variation in the costs of care among patients awaiting liver transplantation. Am J Transplant 2014;14:70e78. 21. McAdam-Marx C, McGarry LJ, Hane CA, et al. All-cause and incremental per patient per year cost associated with chronic hepatitis C virus and associated liver complications in the United States: a managed care perspective. J Managed Care Pharmacy 2011;17:531e546. 22. OPTN/UNOS Liver and Intestinal Organ Transplantation Committee Report to the Board of Directors. Richmond, Virginia June 23-24, 2014. 23. Lai JC, Feng S, Roberts JP. An examination of liver offers to candidates on the liver transplant wait-list. Gastroenterology 2012;143:1261e1265.
Invited Commentary Richard B Freeman Jr, Lebanon, NH
MD, FACS
The team from Massachusetts General Hospital Liver Transplant Program has provided an interesting
1008
Freeman
Invited Commentary
retrospective review of their experience with their patients on the liver transplant waiting list. These investigators compare patients assigned increased priority according to the United Network for Organ Sharing/Organ Procurement and Transplantation Network policy for hepatocellular cancer (HCC) diagnoses with those who are prioritized according to standard criteria in an effort to illustrate effects of the liver allocation policy. The current prioritization scheme was developed more than 13 years ago and was driven by a mortality risk calculation to assign priority to waiting candidates.1 It was recognized back then that, in a risk-of-death driven system, patients with HCC would be disadvantaged because their tumors would likely progress faster than their underlying liver disease. Consequently, policymakers anticipated that patients with HCC would “drop off” of the waiting list due to progression of their cancer more rapidly than they would reach a high mortality risk. For this reason, the policymakers assigned an increased priority for the HCC patients to try and make the drop-out rate for patients with HCC relatively similar to that for patients with non-HCC diagnoses. The point of the HCC exception rule is that policymakers recognized that HCC candidates would not have a high mortality rate on the waiting list and a mortality driven allocation scheme, such as the one that drives allocation of livers to non-HCC candidates, would, in a large number of cases, prevent HCC candidates from getting enough priority to receive a liver offer before their tumor progressed to an unfavorable stage. This policy was developed well before the significant improvements in loco-regional ablative treatments were developed and without good knowledge about the rate of progression for early stage HCC. More recent data have shown that the rate of dropout for HCC patients on the waiting list is actually much lower than originally thought, and for single tumors less than 2 cm, only about 10% will progress beyond Milan criteria within a year, particularly if the tumor is responsive to ablative treatments.2 These data, in combination with comparisons of transplantation rates for HCC and non-HCC patients using the Scientific Registry of Transplant Recipients, competing risks,3 and propensity matching,4 showing that HCC patients have higher transplant rates and lower dropout rates overall, suggest that the priority given to HCC patients under the current system may be too high. Patel and colleagues from the Massachusetts General Hospital retrospectively examined their single-center experience with their waiting list and transplantation rates comparing patients with HCC exception priority with candidates who did not qualify for HCC exception. They found in their patients that the death rate on the
J Am Coll Surg
waiting list was much lower and the transplantation rate was much higher for the candidates with HCC compared with non-HCC patients, and the overall posttransplantation survival was similar at 1 and 5 years between the 2 groups. These results are very consistent with the reports using larger national databases cited above and lend further weight to the suggestion that priority for HCC patients under the current system is too high. It should be noted that the fact that the HCC cohort in this study had a much lower waiting list mortality rate is not surprising because this illustrates precisely why the HCC exception policy was developed. In this case, the overall waiting list removal rate for death or deterioration was similar among the HCC (25.5%) and nonHCC (21.8%, p ¼ 0.32) candidates, suggesting that at least for the overall drop-off rate, the policy was achieving reasonable equity as desired. The authors raise another important point in stating, “In the current study, we have demonstrated that candidates with HCC can wait for relatively long periods while maintaining excellent overall survival post-transplant.” As with all health care, selection of treatments and their efficacy have the ability to affect the cost of care in various ways. These issues can be magnified in transplantation because the allocation process may introduce other incentives that can affect costs. The data here describing the increased number of pretransplantation admissions for the HCC candidates illustrates this fact. There is a strong incentive to slow or halt the progression of HCC while patients wait on the list so they do not progress beyond the tumor burden for which the policy will still confer increased priority. So this center, like many, are willing to readmit HCC patients multiple times for loco-regional treatments before transplantation in an effort to try to control tumor progression. It is interesting to note that it is possible that this process may also be selecting patients for better post-transplantation outcomes because there is evidence that HCC patients who are responsive to loco-regional treatments have lower recurrence rates after transplantation.5 There are a few caveats to interpreting this paper, however. The investigators excluded patients with cholangiocarcinoma and mixed tumors for unclear reasons and do not state how many of these were excluded and whether these received exception points. They also do not mention if patients with other diagnoses for which exception priority was granted were excluded from their analysis. If they were included, it is important to note to which group they were assigned because depending on the overall number, this could skew their results. In addition, most of the other studies looking at the question of HCC priority
Freeman
Vol. 220, No. 6, June 2015
on the waiting list have used a competing risks approach because there is more than 1 outcome possible for patients waiting on the list (transplantation, drop-off, and continued waiting). In the setting of analyzing waiting list dynamics, traditional dichotomous time-to-event statistics tend to overestimate rates because of censoring.6 Moreover, it should always be noted that the transplantation rate is influenced by the organ acceptance behavior on the part of the transplant center. Consequently, these data from this study should be interpreted carefully because the authors did not report the Donor Risk Index for the donors to HCC recipients compared with the Donor Risk Index for the donors to non-HCC recipients. It is possible that their organ acceptance behavior may have more readily accepted higher risk donors for the HCC candidates. If this were the case, the HCC patients would have been exposed to a wider donor pool, which might explain, at least partially, why they had a higher transplantation rate for this cohort in this study. Finally, these authors state, “In the current study, we have demonstrated that candidates with HCC can wait for relatively long periods while maintaining excellent overall survival post-transplant. Furthermore, the HCC candidate had significantly higher percentage of liver transplantation and fewer removals for death on the waitlist, when compared to their non-HCC counterparts. This finding suggests that a national reprioritization of available organs to non-HCC candidates whose survival may be compromised by prolonged waiting periods may be beneficial.” However, in some aspects, the data in this study illustrate that the HCC exception policy is working as designed because the overall removal rates and post-transplantation survival rates are similar for both groups. Nonetheless, it remains true that there are significant geographic differences in transplantation and drop-out rates across the country. However, this study did not provide data or address these differences. It may be overstating the data to suggest that this study has
Invited Commentary
1009
provided a “further assessment of the current system of liver allocation,” as the authors suggest in their introduction because their analysis is limited to only 1 center’s experience in a single region of the allocation and distribution system. In conclusion, these single center data to corroborate the larger national studies insofar as they find higher transplantation rates and lower death rates on the waiting list for HCC patients and post-transplantation outcomes that are similar to those for non-HCC patients. There is a large national effort to re-examine the liver distribution units in an effort to address some of the geographic difference to which these authors refer.7
REFERENCES 1. Freeman RB, Weisner RH, Harper A, et al. The New Liver Allocation System: moving towards evidence-based transplantation policy. Liver Transpl 2002;8:851e858. 2. Mehta N, Dodge JL, Goel A, et al. Identification of liver transplant candidates with hepatocellular carcinoma and a very low dropout risk: implications for the current organ allocation policy. Liver Transpl 2013;12:1343e1353. 3. Washburn K, Edwards E, Harper A, Freeman R. Hepatocellular carcinoma patients are advantaged in the current liver transplant allocation system. Am J Transplant 2010;7: 1643e1648. 4. Freeman RB, Edwards EB, Harper AM. Waiting list removal rates among patients with chronic and malignant liver diseases. Am J Transplant 2006;6:1416e1421. 5. Otto G, Herber S, Heise M, et al. Response to transarterial chemoembolization as a biological selection criterion for liver transplantation in hepatocellular carcinoma. Liver Transpl 2006;8: 1260e1267. 6. Kim WR, Therneau TM, Benson JT, et al. Deaths on the liver transplant waiting list: an analysis of competing risks. Hepatology 2006;2:345e351. 7. Redesigning Liver Distribution to Reduce Variation in Access to Liver Transplantation. A Concept Paper from the OPTN/UNOS Liver and Intestinal Organ Transplantation Committee. Available at: http://optn.transplant.hrsa.gov/ContentDocuments/Liver_ Concepts_2014.pdf. Accessed March 13, 2015.
