20 odd years ago I had testicular cancer. Had all the operations and treatments. Got better, eventually only had to go once a year. Then they said, "you've been coming here for years now, we might as well discharge you, have an x-ray and blood test and get on with the rest of your life".
Then I get a letter saying they found something new on the x-ray. They pod and poke for a couple of years, then say I have terratomas – ended up having 2 years of operations and chemotherapy, far worse than the original lot, but to their surprise get better and I'm still here.
Had I not had that last x-ray the tumours would have spread and probably finished me off, so I suppose my advice would be to get it checked and try to stay positive and I agree that 12 years might have seen a lot of improvements in treatments.