Just as I explained (warned? lamented?) in my May article about mammography, evidence and advice about breast cancer screening continues to emerge at a dizzying rate. The recent findings on breast density presented at the American Association for Cancer Research (AACR) April meeting is still diffusing into the media. You can wade through the evidence at the AACR Web site and by locating the original studies in Pubmed and other databases, but here is a brief summary:

  • Increased breast density translates to greater risk of breast cancer, particularly for women whose breast density increases over time from their own baseline. According to some researchers, increased density may account for up to a four- or fivefold increase in risk.  
  • Breast density is routinely listed on mammogram reports, mainly as a way for radiologists to communicate the difficulty of reading the films, but the statistic may have clinical relevance. Better ways of measuring and describing breast density are under investigation.
  • The AACR defines breast density as: “Mammographic density refers to the amount of white or radiodense area compared to the amount of grey or radiolucent area on a mammogram. The radiodense area is reflective of the amount of ductal and lobular epithelium, connective tissue and fluid in the breast. The radiolucent area is reflective of the amount of fat in the breast.”
  • Studies are underway to investigate which factors impact breast density and how. 
  • For example:
    • Diet
      • For women with strong family histories of breast cancer, certain dietary factors may be linked with density. Can you believe there may be yet another clinical application for vitamin D?
    • Isoflavones
      • Seem innocuous but data scant.
    • Obesity
      • BMI and weight gain, particularly post-menopause, may be associated with increased breast density.  
    • Post-menopausal hormone therapy
      • A hot topic in the medical community, media, and legal system. Data from the Women’s Health Initiativepoints to a connection between breast density and combined estrogen-progestin hormone therapy.  

I predict more data and (hopefully! please!) more clinical guidelines in the next few months from the American Cancer Society, American College of Radiology, and other professional bodies. In the meantime, the Waiting Room will keep tracking new studies. Don’t forget to send your research and anecdotes our way, too!