Study Explores Risk of Invasive Breast Cancer in Women with DCIS

Among women with breast ductal carcinoma in situ (DCIS), evaluation of three molecular markers in a sample of DCIS tissue may provide information about the subsequent risk of invasive breast cancer. These results were published in the Journal of the National Cancer Institute.

DCIS refers to a condition in which abnormal cells are found within a breast duct, but have not spread outside of the duct to other tissues in the breast. It is most commonly detected by screening mammography. If not treated, some cases of DCIS may progress to invasive breast cancer.

The probability that DCIS will progress to invasive cancer is thought to vary widely among women, but thus far it hasn’t been possible to accurately predict risk. As a result, some DCIS patients are probably overtreated and some may be undertreated. Treatment for DCIS often involves lumpectomy plus radiation therapy or mastectomy. Women may also receive hormonal therapy.

An important goal of DCIS research has been to develop a better understanding of DCIS behavior and more individualized approaches to treatment. In the current study, researchers evaluated information from 1162 women diagnosed with DCIS between 1983 and 1994 and treated with lumpectomy alone.

Women with DCIS that was positive for three molecular markers—p16, COX-2, and Ki67—had a higher risk of subsequent invasive breast cancer. Risk was also higher when the DCIS had been detected by palpation of the breast (rather than by screening mammography). Among women with DCIS that was positive for all three markers or had been detected by palpation, the eight-year risk of invasive breast cancer was 20%. Approximately 28% of women fell into this high-risk group. In contrast, among women with DCIS that had been detected by screening mammography and was negative for all three markers, the eight-year risk of invasive breast cancer was 4%. Seventeen percent of women fell into this lowest-risk group.

Research in this area is still at an early stage, and the results of this study are not expected to change patient care in the near future. Nevertheless, this type of research offers hope for improved understanding of DCIS and more individualized DCIS treatment.

Reference: Kerlikowske K, Molinaro AM, Gauthier ML et al. Biomarker Expression and risk of subsequent tumors after initial ductal carcinoma in situ diagnosis. Journal of the National Cancer Institute. 2010;102:627-637.

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