A study led by UCSF doctor Dean Ornish found that lifestyle changes -- instead of invasive treatment -- can reverse cancer. In 30 men with early-stage prostate cancer who chose to enroll in his program, which included a "low-fat, whole-food, plant-based diet, stress management, moderate exercise and plenty of 'psychosocial group support,'" Ornish found that the expression levels of more than 500 genes were changed.