Sounds like we have a similiar situation. My 83 year old father has had it for years which they think came from a tranfusion he had 20 years ago during heart bypass surgery. In the past 5 years he has twice undergone treatment for liver cancer and is currently in remission.
We think by-pass was the cause as well, back in the 70's when it was new, and hep C wasn't even known, let alone tested for.