In one study, researchers identified roughly 280 people who chose “alternative”—that is, unproven—treatments for several non-metastatic cancers. After five years, patients who chose alternative treatments were six times more likely to die of breast cancer, five times more likely to die of colorectal cancer, two times more likely to die of lung cancer, and no more likely to die of prostate cancer (which progresses slowly) than similar patients who chose conventional treatment.