It has been said that with knowledge comes understanding.
A research paper and editorial published last week in JAMA Oncology may have brought knowledge, but if you read various media reports I am not so certain it has clarified understanding. And the distinction is important, because when a woman is confronted with the diagnosis of a "stage O" breast cancer (also known as ductal carcinoma in situ or DCIS), the decisions she makes about treatment can have far-reaching and long-lasting impact for her and those who care about her.
First, some brief background: DCIS was rarely diagnosed before the advent of mammographic screening for breast cancer. Perhaps it was found incidentally when a breast biopsy was done for another reason, or perhaps a woman or her physician felt a mass that turned out to be DCIS. Once mammography became more widespread in the 1970's, we began to see a marked increase in the number of women diagnosed with DCIS. Today, the American Cancer Society estimates that in 2015 slightly more than 60,000 women in the U.S. will be diagnosed with this lesion (compared to 234,190 women who will have a more typical invasive breast cancer).