Influence of Waiting List in Recurrence Disease of Hepatocellular Carcinoma

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.

Impact of successful local ablative bridging therapy prior to liver transplantation on long-term survival in patients with hepatocellular carcinoma in cirrhosis

Background

It has been shown that local ablative procedures enable downsizing, reduce drop-out from the waiting list and improve prognosis after liver transplantation. It is still unclear whether a response to the local ablative therapy is due to a favorable tumor biology or if a real benefit in tumor stabilization exists, particularly in complete pathological response.

Method

Data of 163 HCC patients who underwent liver transplantation were extracted from our prospectively maintained registry. We analyzed the tumor load, pre-transplant α-fetoprotein levels, child stage aside the application and success of local ablative therapies as bridging procedures before transplantation.

Results

87 patients received multiple and/or combined local therapies. In 20 cases, this resulted in a complete remission of the tumor as observed in the explant histology. The other 76 patients underwent no bridging procedure. The observed 5- and 10-year survival rates for patients with bridging were 67% and 47% and without bridging 56% and 46%, respectively. Tumor-related 10-year survival showed a statistically significant difference between both groups (81% versus 59%). In the multivariate analyses bridging, number of lesions and α-fetoprotein level showed an independent statistically significant influence on tumor-related survival in these patients.

Conclusions

Successful local ablative therapy before liver transplantation is an independent statistically significant factor in long-term tumor-related survival for patients with HCC in cirrhosis and reduces tumor recurrences.