This is one of those good stories about modern technology helping support the Hippocratic Oath -- first, do no harm. In this case, how to avoid a painful treatment when possible. Mayo researchers have found that a subset of patients with stage II colon cancer don't benefit from standard chemotherapy. They do well with just surgery. For them, the addition of the chemo simply causes additional discomfort and no benefits. It's not clear why, but it's borne out by clinical studies headed by George Kim, M.D., Mayo oncologist based in Florida. This is another example of what we mean when we talk about Individualized Medicine. A simple test can determine if a patient has the condition -- deficient mismatch repair proteins -- that makes their cancer impervious at least in this stage to the chemo. So, again, in medicine, one approach does not fit all and in this case that may be up to 20 percent of people with stage II colon cancer. For more details on this, check out the Mayo News Blog where you can see Dr. Kim explain his findings. He'll also present them at ASCO, the American Society of Clinical Oncology, in Chicago next week.