Breast cancer diagnosis The beginning to Cappello's activism regarding mammography was in 2003 after her doctor physically identified a
lump on her breast, despite nothing of the sort having been identified in a mammogram weeks earlier and still not being detected in a follow-up mammogram after noticing the lump. An
ultrasound was able to properly identify the mass, however, as a tumor that had already spread to become a
stage 3 lymph node cancer that could only be treated with
chemotherapy and a
mastectomy of the affected breast. The reason why the mammograms had been unsuccessful in identifying the tumor was due to her having
dense breast tissue with low amounts of fat that prevented X-ray scans from penetrating into the tissue and separating darker fat pockets from the bright white tumor tissue. She was also informed that this type of breast tissue increases the risk of cancer forming, despite cancer being difficult to diagnose at the same time for such tissue. Having been unaware of the existence of dense breast tissue or the frequency of it occurring in women, Cappello was "outraged" at not having been informed earlier, as she would have been undergoing ultrasounds rather than mammograms for the prior 10 years if she had known she had the condition. She estimated that due to the growth and extent of the cancer once it was finally detected, it had been growing for several years and had not been identified by any of her scans during that time period. Her doctors also said that informing female patients about the possibility of dense breast tissue was not a part of the "standard protocol" and so she and her husband decided to start advocating for changes to the protocol. and to require that medical insurance would cover the alternative ultrasounds such patients would need. Receiving messages from women across the US wanting such laws passed in their states, Cappello and her husband created the non-profit
Are You Dense? in 2008 to advocate for such legal changes. She would go on to speak on the subject internationally at various medical conventions, including in countries such as Japan, France, Italy and Canada. As of 2019, 37 states had passed a version of the breast density inform law that she had advocated for. A federal notification bill was signed into law in February 2019. Cappello was described by
Imaging Technology News as the "founder of the breast density education movement". ==Personal life==