Hello Tetley,
Sorry to read that your dad's readings are prompting further intervention, but glad that something is being considered.
In 2010 he was diagnosed and it was thought to be a pussycat cancer, slow grower that he would "die with" not "from". It is quite likely that he was told that and was not burying head in sand. Unfortunately pussycats can become tigers it seems.
A couple of factors that you and he might want to consider when you start to look at treatment options. What is the life expectancy in your family line? This may affect his treatment choices?
You should be able to obtain detail of previous biopsies, ask your GP.
Lots of options for him it seems, so take heart.
atb
dave