been shown to lower overall mortality. It is likely that most of the difference in breast cancer screening is due to higher screening rates among young women in the U.S., who may even be harmed by excessive mammograms. There's a similar problem with their analysis of colon cancer screening. They include people age 40-69. Yet standard guidelines do not recommend colon cancer screening in normal risk individuals before age 50. They've fudged the data to get a result they want. Neither the U.S. Preventive Services Task Force nor its Canadian counterpart recommend routine PSA testing because its not at all clear that such testing does more good than harm -- it turns up lots of false positives, including many small tumors that would never cause serious problems if left untreated. Routine screening may well lead to many unnecessary operations that leave men incontinent and impotent. Yet the O'Neill's interpret Canada's lower PSA screening rate as an indicator of poor quality care. We may ultimately find that PSA screening or early mammography saves lives -- or causes more harm than good. But at present, we just don't know whether the lower use of these technologies in Canada is a good thing or a bad one. Their analysis also trumpets the greater number of CT scanners and MRI machines in the U.S. as an indicator of better quality. Yet recent estimates suggest that in the coming years radiation from CT scans may cause as many of 2% of all cancer deaths in