Risk of Invasive Breast Cancer Predicted
Way too many of my women friends have suffered through breast cancer diagnosis, starting with a close friend who died of breast cancer in her early 30s. Her death inspired me to change careers, in hopes of developing better ways to detect and stage breast cancer. Although the focus of my work has now moved on to other medical imaging areas, I still pay particular attention to new breast cancer research.
It seems like there are reports on breast cancer research in the news daily. But my eye was particularly caught by an article published online on April 28, 2010 in the Journal of the National Cancer Institute. A group of researchers, from UCSF Helen Diller Family Comprehensive Cancer Center, are now able to predict whether women with ductal carcinoma in situ are at high or low risk of developing subsequent invasive cancer.
Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. The American Cancer Society estimates that about 60,000 women are diagnosed with DCIS in the U.S. each year. This cancer starts in the milk ducts. It is called non-invasive because it hasn’t spread beyond the milk ducts into any normal surrounding breast tissue. DCIS isn’t life-threatening and it rarely leads to death from breast cancer, but having DCIS can increase your risk of developing an invasive breast cancer in the future. Approximately 11 out of 100 women diagnosed with DCIS and treated with a lumpectomy only go on to develop invasive cancer within 8 years, and about the same number go on to develop subsequent DCIS within 8 years. That means that the majority of such women have no further tumors, but these women typically still go through some form of aggressive treatment.
So we really need a way to predict which women with DCIS have a high risk of developing subsequent tumors. The UCSF scientists report that they’ve discovered a method to do just that. They collected and analyzed data for 1162 women aged 40 years or older, who were diagnosed with DCIS and treated with a lumpectomy alone in the San Francisco Bay Area. They followed and measured clinical, histopathologic, and molecular characteristics of subsequent tumors for this large population (from 63 hospitals) for 8 years.
They found that the risk of subsequent invasive cancer was significantly increased among women whose initial DCIS was detected by palpation compared with those detected by mammography. They also found that DCIS lesions that were “triple positive” for the expression of biomarkers p16, COX-2and Ki67 had an even higher risk of subsequent invasive cancer. However, these factors were not associated with increased risk of subsequent DCIS. An independent set of biomarker expression and conditions was identified for increased risk of subsequent DCIS, with the lowest risk group having disease-free surgical margins of 10 mm or larger.
Based on their findings, the UCSF scientist were able to stratify the women into 4 categories for risk of subsequent invasive cancer — Lowest (17%), Low (27%), Intermediate (28%) and High (28%). The lowest risk group had only a 4% risk of developing invasive cancer within 8 years, whereas the high risk group had a 20% risk. A similar stratification was performed for risk of subsequent DCIS with similar results.
Hopefully this new method of predicting risk for subsequent cancers will help women with DCIS chose the proper treatment. Karla Kerlikowske, the lead author, states “It will lead to a more personalized approach to treatment. As many as 44 percent of the patients (i.e., lowest and low risk groups) with DCIS may not require any further treatment, and can rely on surveillance.”