Charles - my son had some major stress brought on by a divorce before he developed his cancer. He had also been hospitalized before his divorce for depression brought on by some clergy abuse he suffered as a child. Right now he is in a much better place with a really great girlfriend and wonderful friends. Just the suspicion that stress could be a factor behooves us to "nip it in the bud" before it takes control of us. When I was experiencing stress and worrying over my son, I found that when things got too bad, I would try to allow myself only 5 minutes for giving myself some compassion and then when the five minutes were up, I would try do something physical like exercising even if it was just bending over to touch my toes. Keeping busy helps.