“Fred was diagnosed 3 years ago and would start being president in 2 years. That means he would be 5 years into an incurable disease with a median 10 year surival.”....
Right there, you gave him a median 10 years to live.
I suspect that if someone delved into the “median 10 year survival” statistic, it could well be very dependent on whether the victim discovered this by some acute “sickness” or by a more routine “checkup”. There certainly many “good lymphoma” survivors apparently going to die of something other than the very treatable cancer they have. I know some of them. On the other hand, there are some who don’t survive long.
I suspect that those who die from this had a real bad and pervasive case before they ever found out about it, and they skew the statistics to the short end, but the fact that we don’t live forever cuts down even the longest lived survivor ... so that caps the high end to something less than “median 80 years survival” for certain.