The media drawing link between cancer and stress, and prevention through mind-body medicine..."practices such as meditation, yoga, tai chi, self-hypnosis or guided imagery..have been shown to be quite useful in helping to manage stress. Managing stress, alongside conventional treatment and a full lifestyle programmatic approach, may ultimately improve cancer outcomes"... 

 http://www.cnn.com/2012/09/14/health/stress-cancer-survival-enayati/index.html