Women with ductal carcinoma in situ (DCIS) who have mammographically dense breasts may be at increased risk for subsequent breast cancer, especially in the contralateral breast, researchers at Kaiser Permanente report.
To confirm findings of a previous study showing that women with DCIS who had higher mammographic density had about two to three times higher risk for a second breast cancer, Laurel A. Habel, PhD, research scientist at Kaiser Permanente's Division of Research, and associates conducted a larger cohort study. The subjects were 935 women diagnosed with DCIS who were treated with breast-conserving surgery. The results are published in the October issue of Cancer Epidemiology, Biomarkers & Prevention.
Of the 935 patients, 164 (18%) had a subsequent ipsilateral breast cancer, and 59 (6%) had a new primary cancer in the contralateral breast during follow-up (median, 103 months). Women whose total area of breast density values were in the upper 20% were at higher risk for invasive cancer in either breast or any cancer (DCIS or invasive) in the ipsilateral or contralateral breast compared with those whose breast density values were in the lowest 20%.
Habel said that further studies will be needed to confirm these result and determine whether information on breast density can aid in risk assessment and decisions about treatment options.
"Information on mammographic density may help with treatment decisions for ductal carcinoma in situ patients," she said. "While it's not a strong enough risk factor on its own, it may be possible to combine it with other factors to improve risk assessment and inform treatment decisions."