Where to find published results of positive psychology cancer treatment study mentioned in Martin Seligman's book? In Dr. Martin Seligman's book, "Learned Optimism: How to Change Your Mind and Your Life", there was mention of a study involving teaching cancer patients to fight learned helplessness.

I believe this study commenced around 1990, but could not find any information on the study online. 

I would like to know if now, more than 20 years later, if the group showed improvements in battling the cancer.
I'm not sure what study Seligman is referring to, but I can suggest that you look into Shelley Taylor's work on positive illusions. Her original 1983 work looked into the coping mechanisms of a group of cancer patients undergoing treatment, and followed them into their lives after recovering from their illness. She found that individuals who felt that they were better than their peers at dealing with the cancer, felt that they had some control over the cancer's course, and that their future was brighter than that of others, had a better chance of returning to or exceeding their original quality of life before the illness. These beliefs are called "positive illusions", and are outlined clearly in Taylor &amp; Brown (1994). 

Hope this helps!