A new study has reported a set of factors that can help predict which women with ductal carcinoma in situ (DCIS) are most likely to progress to invasive breast cancer. Previous studies have failed to identify characteristics of women with DCIS that are associated with risk of recurrence or progression. For example, histopathological information such tumor grade has not been found to be useful. The study included 1,162 women at least 40 years of age who were diagnosed with DCIS and treated with lumpectomy alone between 1983 and 1994. Clinical and pathological characteristics, as well as information on subsequent tumors, were collected.

Subsequent tumors (found in 324 of the women) were defined as either invasive breast cancer or DCIS diagnosed in the same breast as the initial DCIS lesion, or regional or distant invasive breast cancer. Estrogen receptor (ER), progesterone receptor (PR), HER2 expression, Ki67 antigen, p53, p16, and cyclooxygenase-2 (COX-2) were assessed using samples of the original DCIS tissue from the study participants.

It was found that factors associated with subsequent invasive breast cancer tended to be different from those associated with subsequent additional DCIS. The eight-year risk of subsequent invasive cancer was higher for women with initial DCIS lesions that were found by palpation (lumps or thickening that could be felt by hand) or that were p16, COX-2, and Ki67 triple positive (p16+COX-2+Ki67+) than for women with DCIS lesions that were detected by screening mammography and were p16, COX-2, and Ki67 triple negative (p16-COX-2-Ki67-). On the other hand, nuclear grade was not correlated with subsequent invasive breast cancer. Eight-year risk of subsequent additional DCIS was found to be highest for women with DCIS lesions that had disease-free margins of 1 mm or greater combined with either ER-ERBB2+Ki67+ or p16+COX-2-Ki67+ status. The authors conclude that they have identified biomarkers that can identify which women diagnosed with DCIS are at high or low risk of subsequent invasive cancer.