The Liver Flush is probably thousands of years old therapy, traditionally practiced in many countries around mediterranean sea.
I doubt, who ever was first to advocate Liver Flushing (hundreds or thousands of years ago), I doubt that person died of cancer, considering that just 200 years ago, cancer was extremely rare disease, and less then 1% of people were actually dying of cancer!
Several Liver Flushing recipes where published in books in the last 70 years.