Mel -
Maybe this will help.
The answer to your question seems to be finding out what the accepted PCa survival prognosis was around 2011.
A way to get to that information would be to consult medical articles on the topic from that date, 2011, or even earlier, to see what the expert thinking was at that time.
This can be done in Google (must be in Google) by
1. searching (just like this):
prostate cancer survival rate before:2012
2. results are articles that are on that topic and from before 2012 (therefore 2011 or earlier). (One can also tailor the search time period, such as
after:2000 before:2012
and such, to narrow the time period).
For example, here's an article retrieved from 2006 that talks about
" ... survival probability in men with clinically localized prostate cancer":
https://pubmed.ncbi.nlm.nih.gov/17169648/that is, the thinking in 2006.
Skimming the other results from using the above search should retrieve similar articles from back then.