Impact of waiting time on post-transplant survival for recipients with hepatocellular carcinoma: A natural experiment randomized by blood group

Background & Aims

When listing for liver transplantation, one can transplant as soon as possible or introduce a test-of-time to better select patients, as the tumor's biological behavior is observed. Knowing the degree of harm caused by time itself is essential to advise patients and decide on the maximum duration of the test-of-time. Therefore, we investigated the causal effect of waiting time on post-transplant survival for patients with hepatocellular carcinoma.

Methods

We analyzed the UNOS-OPTN dataset and exploited a natural experiment created by blood groups. Relations between variables and assumptions were described in a causal graph. Selection bias was addressed by inverse probability weighting. Confounding was avoided using instrumental variable analysis, with an additive hazards model in the second stage. The causal effect was evaluated by estimating the difference in 5-year overall survival if all patients waited 2 months instead of 12 months. Upper bounds of the test-of-time were evaluated for probable scenarios by means of simulation.

Results

The F-statistic of the first stage was 86.3. The effect of waiting 12 months vs. 2 months corresponded with a drop in overall survival rate of 5.07% (95% CI 0.277-9.69) and 8.33% (95% CI 0.47-15.60) at 5- and 10-years post-transplant, respectively. The median survival dropped by 3.41 years from 16.21 years (95% CI 15.98-16.60) for those waiting 2 months to 12.80 years (95% CI 10.72-15.90) for those waiting 12 months.

Conclusions

From a patient's perspective, the choice between ablate-and-wait vs. immediate transplantation is in favor of immediate transplantation. From a policy perspective, the extra waiting time can be used to increase the utility of scarce donor livers. However, the duration of the test-of-time is bounded, and it likely should not exceed 8 months.

Impact and implications

When listing patients with liver cancer for transplantation, it is unclear whether a test-of-time or immediate transplantation offer better outcomes at the population level. In this study, we found that increased liver transplant waiting times are detrimental in patients with liver cancer. Furthermore, our simulation showed that a pre-operative observational period can be useful to ensure good donor liver allocation, but that its duration should not exceed 8 months.

Direct-Acting Antiviral Therapy in Liver Transplant Patients With Hepatocellular Carcinoma and Hepatitis C

Direct-acting antivirals (DAA) are highly effective for the treatment of hepatitis C (HCV), although there are limited data on the safety and efficacy of DAA therapy in hepatitis C-positive individuals awaiting liver transplantation for hepatocellular carcinoma (HCC).

Outcomes of Liver Transplantation for Hepatocellular Carcinoma Beyond the University of California San Francisco Criteria: A Single-center Experience

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common primary malignant liver tumor. Currently, liver transplantation may be the optimal treatment for HCC in cirrhotic patients. Patient selection is currently based on tumor size. We developed a program to offer liver transplantation to selected patients with HCC outside of traditional criteria.

METHODS

Retrospective review for patients transplanted with HCC between April 2008 and June 2017. Patients were grouped by tumor size according to Milan, University of California San Francisco (UCSF), and outside UCSF criteria. Patient demographics, laboratory values, and outcomes were compared. Patients radiographically outside Milan criteria were selected based on tumor control with locoregional therapy (LRT) and 9 months of stability from LRT. α-fetoprotein values were not exclusionary.

RESULTS

Two hundred twenty HCC patients were transplanted, 138 inside Milan, 23 inside UCSF, and 59 beyond UCSF criteria. Patient survival was equivalent at 1, 3, or 5 years despite pathologic tumor size. Waiting time to transplantation was not significantly different at an average of 344 days. In patients outside UCSF, tumor recurrence was equivalent to Milan and UCSF criteria recipients who waited >9 months from LRT. Although tumor recurrence was more likely in outside of UCSF patients (3% versus 9% versus 15%; P = 0.02), recurrence-free survival only trended toward significance among the groups (P = 0.053).

CONCLUSIONS

Selective patients outside of traditional size criteria can be effectively transplanted with equivalent survival to patients with smaller tumors, even when pathologic tumor burden is considered. Tumor stability over time can be used to help select patients for transplantation.

Outcomes in Hepatocellular Carcinoma Liver Transplantation before and after the Mandated Six-Month Wait Time

The United Network for Organ Sharing (UNOS) implemented a policy that requires patients with hepatocellular carcinoma seeking liver transplantation to wait six months before being granted Model for End-Stage Liver Disease exception points. We investigated the difference in resource utilization between patients who underwent liver transplantation before and after the present policy. We conducted a retrospective cohort study of adult liver transplants from 2013 to 2018. Patients were classified into prepolicy or postpolicy groups based on 964 days before or after the wait-time policy. We also retrieved national survival outcome data from United Network for Organ Sharing. Differences across compared groups for continuous variables were assessed using the independent sample t test, and the chi-squared test was used for binary variables. We found statistical differences in recipient age ( P = 0.005), days on wait-list ( P = 0.001), sustained viro-logical response ( P < 0.001), and hepatocellular carcinoma recurrence one year posttransplant ( P = 0.04). There were statistically significant differences in the number of treatment days pretransplant and length of transplant admission stay, indicating an increase in resource utilization in the postpolicy group. No statistically significant differences were found between groups in one-year graft or patient survival despite an observed increase in resource utilization by the hepatocellular carcinoma postpolicy group.

The mRECIST Classification Provides Insight into Tumor Biology for Patients With Hepatocellular Carcinoma Awaiting Liver Transplantation

With recent changes in United Network for Organ Sharing policy, patients in the United States with hepatocellular carcinoma (HCC) are likely to spend more time on the liver transplantation (LT) waiting list. The increasing wait time will allow for an opportunity to assess tumor biology prior to LT. Modified Response Evaluation Criteria in Solid Tumors (mRECIST) paradigm provides such a framework for this assessment, and yet little is understood of its utility as it would apply for patients listed for LT in the United States. Through a collaboration between the University of California, San Francisco, and the Mayo Clinic, Jacksonville, Florida, the experience of 772 patients listed for LT were retrospectively reviewed to study the impact of immediate mRECIST classification following locoregional therapy (LRT) on pre- and post-LT outcomes. Patients who had progression of disease (PD; n = 72), failed to respond to LRT (n = 89) at any time point, or did not achieve radiologic complete response (CR; n = 224) were all at significant risk for wait-list dropout (odds ratio [OR] = 12.11, 4.81, and 2.48; respectively). CR identified a cohort of patients who were at a reduced risk for wait-list dropout. However, 24.9% eventually required further intervention while waiting for transplant, and as many as 82.4% were found to have residual HCC on explant pathology. Failure to respond to LRT was associated with increased risk for recurrence (OR = 3.00) more so than PD (OR = 1.36), suggesting that despite PD, patients who eventually can respond to LRT may represent favorable candidates for LT. In conclusion, for patients awaiting LT, the mRECIST assessment provides critical guidance for patient management. Although PD portends a poor prognosis, our findings suggest that further aggressive LRT should be pursued because a response to LRT may yield acceptable results for patients awaiting LT as well as after LT.

Liver transplantation for intrahepatic cholangiocarcinoma

Although hepatocellular carcinoma (HCC) has become a common indication for liver transplantation (LT), intrahepatic cholangiocarcinoma (ICC) and combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) are historically contraindicated due to their aggressive behavior. On the basis of recent experiences, some groups have proposed a clinical trial investigating the role of LT for patients with early cholangiocarcinoma (CCA), defined as a single lesion ≤ 2 cm. The purpose of this study is to assess the clinicopathologic features and outcomes following LT for patients who were initially diagnosed with HCC and subsequently found to have either ICC or cHCC-CCA on explant. Patients with the diagnosis of primary liver cancer (PLC) after LT from a single center were retrospectively reviewed. Outcomes for patients with early CCA were compared with patients with HCC within Milan criteria (MC). Out of 618 patients transplanted with PLC, 44 patients were found to have CCA on explant. On the basis of preoperative imaging, 12 patients met criteria for early CCA and were compared with 319 patients who had HCC within MC. The 1- and 5-year overall survival for early CCA versus HCC was 63.6% versus 90.0% and 63.6% versus 70.3% (log-rank, P = 0.25), respectively. Overall recurrence was 33.3% for early CCA versus 11% for HCC. On explant the patients with CCA were more likely understaged with higher tumor grade and vascular invasion. In conclusion, patients with CCA present a diagnostic challenge, which often leads to the finding of more aggressive lesions on explant after LT, higher recurrence rates, and worse post-LT survival. Careful consideration of this diagnostic conundrum needs to be made before a clinical trial is undertaken. Liver Transplantation 24 634-644 2018 AASLD.

Results of Liver Transplantation for Hepatocellular Carcinoma in a Multicenter Latin American Cohort Study

BACKGROUND AND AIMS

Heterogeneous data has been reported regarding liver transplantation (LT) for hepatocellular carcinoma (HCC) in Latin America. We aimed to describe treatment during waiting list, survival and recurrence of HCC after LT in a multicenter study from Latin America.

MATERIAL AND METHODS

Patients with HCC diagnosed prior to transplant (cHCC) and incidentally found in the explanted liver (iHCC) were included. Imaging-explanted features were compared in cHCC (non-discordant if pre and post-LT were within Milan, discordant if pre-LT was within and post-LT exceeding Milan).

RESULTS

Overall, 435 patients with cHCC and 92 with iHCC were included. At listing, 81% and 91% of cHCC patients were within Milan and San Francisco criteria (UCSF), respectively. Five-year survival and recurrence rates for cHCC within Milan, exceeding Milan/within UCSF and beyond UCSF were 71% and 16%; 66% and 26%; 46% and 55%, respectively. Locoregional treatment prior to LT was performed in 39% of cHCC within Milan, in 53% beyond Milan/within UCSF and in 83% exceeding UCSF (p &lt; 0.0001). This treatment difference was not observed according to AFP values (≤100, 44%; 101-1,000, 39%, and &gt; 1,000 ng/mL 64%; p = 0.12). Discordant imaging-explanted data was observed in 29% of cHCC, showing lower survival HR 2.02 (CI 1.29; 3.15) and higher recurrence rates HR 2.34 when compared to AFP &lt;100 ng/mL. Serum AFP &gt; 1,000 ng/mL at listing was independently associated with a higher 5-year recurrence rate and a HR of 3.24 when compared to AFP &lt;100 ng/mL.

CONCLUSION

Although overall results are comparable to other regions worldwide, pre-LT treatment not only considering imaging data but also AFP values should be contemplated during the next years.