I had testicular cancer a few years back which is now in recession. I am a pilot and I was off flying for 9 months (3 months for the chemo course and then 6 months which the CAA mandate).
I am now flying Public Transport with a Class 1 Restricted medical (as or with co-pilot or whatever the new JAA term is). I have regular check-ups and I have to have copies of the reports sent to the CAA. They do get a bit stroppy sometimes if they haven't received one in a while, but I must say that they were very helpful during the period of chemo and the 6 months afterwards and were eager to allow me back to flying.
Hope that helps a bit?