Biomarkers may aid treatment decisions in DCIS

Certain biomarkers may help predict risk for and severity of recurrent disease in women with ductal carcinoma in situ (DCIS), according to a new study.

Researchers performed a nested case-control study of 1,162 women diagnosed with DCIS and treated with lumpectomy alone from 1983 to 1994. The study looked at clinical characteristics of DCIS, subsequent disease (invasive breast cancer, DCIS in the ipsilateral breast or DCIS at a regional or distant site more than six months after initial DCIS treatment), and data from pathology reviews and immunohistochemical staining. The authors examined factors related to subsequent invasive cancer and subsequent DCIS and calculated patients' eight-year risk. The study results were published early online April 28 by the Journal of the National Cancer Institute.

Eight-year risk for subsequent invasive cancer was higher in women whose DCIS was detected on palpation or whose lesions were positive for p16, cyclooxygenase-2 (COX-2) and Ki67 antigen (19.6%; 95% CI, 19.0% to 21.3%) than in women whose DCIS was detected on mammography and in which the same three biomarkers were negative (4.1%; 95% CI, 3.4% to 5.0%) (P=0.018). Eight-year risk for subsequent DCIS, meanwhile, was greatest for women whose DCIS lesions had disease-free margins of at least 1 mm and one of the following biomarker profiles: estrogen-receptor negative, epidermal growth factor receptor-2 positive, Ki67 antigen positive or p16 positive, COX-2 negative and Ki67 antigen positive. Five- and eight-year risk for subsequent DCIS was lowest in women whose disease-free margins were 10 mm or more. Nuclear grade was not associated with future invasive cancer.

The study had several potential limitations, including retrospective assessment of clinical factors and possible over- or underestimation of subsequent tumor risk. However, the authors concluded that biomarkers can be useful in helping to quantify future cancer risk in women with DCIS. “We show that the mode of detection and the biomarkers p16, COX-2, and Ki67 may be used to help stratify a woman's risk of subsequent invasive cancer and to help her decide whether she should undergo adjuvant therapies,” the authors wrote.

Another study released last week reported that established breast cancer risk factors in non-Hispanic white women do not necessarily apply to Hispanic populations. Using data from the population-based, case-controlled 4-Corners Breast Study, the authors found that Hispanic women with breast cancer were more likely to have characteristics usually associated with lower breast cancer risk, such as earlier age at first childbirth and less hormone use. Overall, 62% to 75% of breast cancer cases could be attributed to established risk factors in non-Hispanic white women versus 7% to 36% of breast cancer cases in Hispanic women. The study was published online April 26 by Cancer.