Breast density & cancer risk
Manjula Puthenedam, PhD
Mammographic density makes the detection of cancer by mammography difficult and is associated with an increased risk of breast cancer. Recently, researchers have shown that women with dense breasts may be at higher risk of subsequent breast cancer.

In a study published online Oct. 7 in Cancer Epidemiology, Biomarkers & Prevention, patients with ductal carcinoma in situ (DCIS) who have higher mammographic density may be at increased risk for subsequent breast cancer, especially in the breast opposite to the one with the initial cancer. Of the 935 eligible DCIS patients, 64 had a subsequent ipsilateral breast cancer and 59 had a new primary cancer in the contralateral breast during follow-up.

The researchers also found that those with the greatest total area of density (upper 20 percent of values) were at increased risk for invasive disease in either or any cancer (DCIS or invasive) in the ipsilateral or contralateral breast compared with those with the smallest area of density (bottom 20 percent).

Another study published this month in the Annals of Surgical Oncology confirmed that the association between increased mammographic breast density, young patient age, and occult tumors persist despite improvements in mammographic technique.

Greater density was associated with increased mastectomy use, with 61 percent of the extremely dense group having mastectomy versus 43 percent of those of lesser density. The researchers identified an association between extremely dense breasts and the luminal A molecular subtype of breast cancer, as well as between extremely dense breasts and cancers of lobular histology.

These findings on breast density could be important for physicians to improve risk assessment and in making treatment decisions.

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Manjula Puthenedam, PhD,
Associate Editor, Molecular Imaging Insight