Steve
While I haven't suffered a recurrence (said with all fingers crossed) my battle taught me that I have to keep "living"...that means planning, and doing, things I want to do, and not hesitating or saying to myself "better wait and see".

It gives you a goal to shoot for; that's hugely important in everyone's life, regardless of what circumstances you find yourself in.

The biggest mistake I made during treatment was putting my life completely on hold. When I came through the darkest parts of recovery, I found that all of the things I'd wanted to do a year earlier had passed my by, and I had no plan for "now".

I'm still nowhere near 100%, but I set a goal to return to work, and I did. I am effectively disabled from the surgery to my leg, but I work full days, and travel...now I do it with a cane and a segway to get around.

My father is in end stage lung cancer, and we will likely lose him in the next month or so, and my father-in-law had surgery for aggressive kidney cancer this past week, and the prognosis isn't good. Even with that on our plates, we are planning a trip with our adult children and their spouses to China in November; I plan on having a family portrait taken on the Great Wall for Christmas cards.

That's not intended to sound callous about my familie's bad luck with the beast, and the sorrow it has brought to us; we will go to China because we (I, especially) need to follow through with our life plan. After all, I don't know what next month, or next year may bring, and I would hate to face another round with the beast knowing I'd put something else off in anticipation of more problems.

I say sign up for the Ironman, and use it as your goal for recovery. Think of it as a reward to yourself if you need to, but do it. The achievment you'll feel will be the sweetest victory you've ever enjoyed.

my two cents...your mileage may vary
Wayne