Speaking from the perspective of a 5+ yr cancer survivor (breast), I would avoid getting anything with references to "lost a nut", etc. While it may seem funny and cool now, down the road he will look on those things and it could move him back to the time of uncertainty and fear. I love the idea of the donation to the American Cancer Society, and wholeheartedly agree with the family-oriented gift. If they have kids, then offer babysitting and a night out at a hotel/B&B. When I was finished with my treatments, we had a BBQ for all of our friends who supported us during the treatments, and then our family took a private road trip. Each of the stops was linked to a stage in treatment, so when we reached the final one, it gave all of us physical closure to the ordeal. Maybe something like that would appeal to them, too, though on a smaller scale. Yellow may become a trigger color for him, with all of the Lance Armstrong bracelets around, or it might be empowering. Avoid anything kitschy. JMO!