23 Aug 2012

Prioritization

Along the same line, I can ask a series of questions that do not beg textbook answers. Students who have gone through liberal studies in secondary school must find these very easy.

“Now that we adopt the Model for End-stage Liver Disease (MELD) score instead of Child-Pugh score for prioritizing transplantation listing, what types of patients are most likely to be affected?”

“Do you think patients with liver cancer and cirrhosis instead of cirrhosis alone should jump the queue?”

“Should an organ be given to the sickest person or a person with the biggest survival gain after liver transplantation?”

The rationale behind the last question may not be immediately obvious. Unlike kidney failure, we cannot maintain life of a liver failure patient by dialysis. Therefore, the waiting time does not count. If a patient has mild disease, he will not get an organ even if he has been listed for 20 years (In reality this is not possible because he would have been delisted). Instead, the organ will be given to the sickest patient based on the MELD score.

Now is the more difficult part. For obvious reasons, the sickest person also has higher operative risk and is more likely to develop complications. His survival after liver transplantation is not the same as that of a person with milder disease. To complicate matters further, a patient with liver cancer is also at risk of cancer recurrence.

Suppose we have two patients. The first has liver failure, locally advanced liver cancer and multiple other medical diseases. His chance of survival without transplantation is zero while that after transplantation is around 20%. The second patient has advanced cirrhosis but is otherwise young and free of other diseases. His chance of survival without transplantation is 30% but is up to 70% 5 years after transplantation. Which one should receive the organ? If you choose the latter because the first patient is too ill, what is the difference in survival gain that you would accept?

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