(May 2010) Scientists for the first time have discovered a way to predict whether women with the most common form of non-invasive breast cancer — ductal carcinoma in situ (DCIS) — are at risk of developing more invasive tumors in later life. The study appears online in The Journal of the National Cancer Institute.
The finding will allow women with DCIS to be more selective about their course of treatment and, potentially, avoid aggressive forms of treatment such as complete mastectomy or radiation.
“With these findings, a patient will be able to assess her risk of subsequently developing invasive cancer or DCIS — or not developing further tumors,” said Annette Molinaro, Ph.D., an assistant professor of biostatistics at the Yale School of Public Health and one of the study’s lead authors. “This separation into risk groups will assist in determining an appropriate treatment regimen tailored to an individual woman’s clinical profile.”
Researchers followed the medical histories of 1,162 women who were diagnosed with DCIS and treated with lumpectomy. The researchers found that two factors were predictors of risk of developing invasive cancer within eight years after being diagnosed with DCIS: the method by which it was detected and the expression of several biomarkers. The findings showed that a breast lump that is diagnosed as DCIS was more predictive of a high risk of subsequent invasive cancer than DCIS diagnosis by mammography.
The study also found that different combinations of biomarkers measured on the initial DCIS tissue were associated with varying levels of risk of invasive cancer or DCIS. These biomarkers include the estrogen and progesterone receptors.
Scientists have been trying for more than 20 years to determine a way to identify which women with DCIS are at risk of developing invasive cancer later, but until now have been unable to stratify women into risk groups. DCIS rarely leads to death from breast cancer. Approximately 11 out of 100 women treated by lumpectomy go on to develop invasive cancer within eight years of the initial diagnosis of DCIS, and only 1 percent to 2 percent of women die of breast cancer within 10 years of diagnosis. But women diagnosed with DCIS have historically had an inaccurate perception of their risk of later developing invasive cancer, and as a result have chosen fairly aggressive treatments.
Approximately 35 percent of women currently opt for a lumpectomy, 25 percent for a complete mastectomy, 3 percent to 5 percent for active surveillance only and the remainder for lumpectomy plus radiation or hormone treatment, or both. According to the study, the group of patients with the lowest risk has only a 2 percent chance of developing invasive cancer at five years and a 4 percent chance at eight years