WSJ: Early detection of breast cancer backed by U.K. study

This article can be found at wsj.com By MELINDA BECK Dec. 4, 2015  Detecting and treating an early form of breast cancer lowers the number of invasive breast cancers found over the next three years, according to a study of 5.2 million U.K. women. The study, published on Friday in the journal Lancet Oncology, provides reassurance that early cancer detection is beneficial amid growing concern that it also leads to unnecessary treatment, the researchers said. Ductal carcinoma in situ, or DCIS, involves clusters of abnormal cells confined to the milk ducts of the breast. It was seldom seen before mammograms came into widespread use in the 1980s but now accounts for nearly one-quarter of all breast cancers detected by screening—some 60,000 cases a year in the U.S. Some experts argue that DCIS shouldn’t be labeled cancer at all, since it’s unclear whether it will spread outside the milk ducts. Yet virtually all DCIS cases are treated as if they were cancer, with lumpectomies, with or without radiation, or mastectomies. Since DCIS is seldom left untreated, there is little data on how many cases would become invasive cancers, although some estimates suggest that as few as 20% progress. In the latest study, researchers at Queen Mary University of London analyzed records of 5.2 million women ages 50 to 64 in England, Wales and Northern Ireland who had mammograms between 2003 and 2007. In 90% of the local screening areas, for every three cases of DCIS detected and treated, one fewer case of invasive cancer was diagnosed in the following three years than would have been without early intervention, the study found....