Sherrie,
I don't believe I have ever heard of a motocross crash being one of the risk factors for this type of cancer

. Most likely Dan just has the usual swelling you would experience when you have trauma, compounded by maybe less blood flow to that area because of the radiation. Try to keep focused on the housecleaning and the three great years! I know once we experience this dreaded disease, it seems to linger in many ways. I am glad Dan has had 3 years and counting.
Ed