This week brings very exciting news, but everybody seems worried that we’ll misunderstand and read too much into it. There are very few cancers for which we have a good screening test.  A good screening test is a test that is done on people without any signs or symptoms of cancer and that diagnoses the cancer accurately enough at an early enough stage so that lives are saved.  Mammograms save lives from breast cancer.  Pap smears save lives from cervical cancer.  Screening for colon cancer save...