Breast Cancer News
Monday, April 28, 2008
Biological Markers in DCIS Tumors Predict Risk for Invasive Breast Cancer
Researchers identify molecular markers that may predict whether a woman is likely to develop invasive cancer after initial diagnosis with ductal cardinoma in situ
By Anna Shaffer, LBBC Staff; reviewed by Thea D. Tlsty, PhD
ML Gauthier, et al. Conditional expression of stress proteins in DCIS predicts tumor formation. 30th Annual San Antonio Breast Cancer Symposium. December 2007. Abstract 49.
An analysis of the tumors of women diagnosed with ductal carcinoma in situ, or DCIS, identified biological markers that may predict whether invasive breast cancer is likely to develop.
The study, presented at the
30th Annual San Antonio Breast Cancer Symposium, provides critical information that may lead to the development of tests to help doctors determine whether a woman should receive more or less aggressive therapy.
What Is DCIS, and How Does It Differ From Invasive Breast Cancer?
Ductal carcinoma in situ (DCIS), also called
intraductal carcinoma, is when abnormal cells stay inside the walls of the breast ducts and do not spread to other tissues in the breast. DCIS is the most common type of non-invasive breast cancer—about one out of every five new breast cancer cases will be DCIS, according to the American Cancer Society.
In some cases, DCIS may become invasive cancer. Invasive cancer grows beyond its original site in the breast and into other tissues. However, the majority of DCIS tumors are not associated with future invasive tumors—only 12 percent to 15 percent of women diagnosed with DCIS develop a subsequent invasive breast cancer within ten years after lumpectomy.
DCIS Study Background
Doctors are still learning how to predict which DCIS tumors will become invasive. Because of this uncertainty, all women diagnosed with DCIS tend to be offered similar treatment options to reduce the risk for recurrence and the risk of developing an invasive cancer in the same or other breast. Treatment for DCIS usually consists of the surgical removal of the affected area of the breast followed by radiation treatment. Because only a small percentage of women diagnosed with DCIS develop invasive breast cancer, many women diagnosed with DCIS who opt for surgery, with or without adjuvant treatment, may be getting over-treated.
The study, headed by a team of scientists from the University of California San Francisco, sought to identify characteristics of DCIS called biological markers or
biomarkers that predict future development of invasive tumors. Doing so may allow doctors to assess a woman’s individual risk for invasive breast cancers and avoid over- and under-treatment.
DCIS Study Design
The researchers believed cells capable of responding to stress signals that cause cells to stop growing would not form future invasive tumors, while cells that bypass stress signals (and keep growing) would be more likely to progress and form invasive tumors.
They studied molecular characteristics of tumor cells and their association with outcome in a group of 70 women diagnosed with DCIS and treated by lumpectomy alone. Of these women, 32 later developed invasive breast cancer and 38 did not. The researchers followed these women for 20 years, then extended the study to a group of 162 women diagnosed with DCIS, 75 who later developed invasive breast cancer and 87 who did not.
What the DCIS Study Showed
The researchers found that the presence of two biomarkers of stress activation, a tumor suppressor gene called p16 and an enzyme called COX2, when combined with a marker that shows the absence or presence of cell growth, indicates a highly aggressive type of DCIS that shares characteristics with invasive breast cancer. The biomarkers found in this type of DCIS are associated with a high likelihood of future development of invasive disease. Study results confirmed that these markers faithfully identify women at high versus low risk for future invasive breast cancer.
The finding that the presence of biomarkers in DCIS tumors corresponds to a greatly increased risk of developing future invasive breast cancer suggests that these tumors can be analyzed far in advance of the development of invasive disease. If doctors look for these biomarkers when a woman is diagnosed with DCIS, it can present opportunities for them to tailor treatment accordingly based on each woman’s individual risk.
What Does the DCIS Study Mean for Me?
If you have been diagnosed with DCIS, this study provides critical information that may lead to the development of tests that can reliably identify the biomarkers and help doctors determine whether a woman should receive more or less aggressive therapy. However, these results are early and more research is needed to determine the nature and treatment of in situ breast disease. These initial results need to be validated in an independent group of cases before a clinical test can be offered to women.
Doctors are still learning how to predict which DCIS will become invasive. Other factors that seem to play a role in predicting future invasive breast cancers include the size of the area affected by DCIS, the degree of cancerous change in the abnormal cells and, in women having surgery that conserves the breast, the proximity of the margins (the border of tissue around the cancer) to the surrounding tumor that has been removed.
If you have been diagnosed with DCIS, you may want to ask your healthcare team about clinical trials studying tests and treatments for DCIS. These conversations also can help you understand the pathology of your specific disease, your level of risk and your treatment options. You should also ask your doctor about lifestyle changes that may reduce your risk of developing a new breast cancer.
For more information on DCIS, read the transcript from our teleconference
DCIS and LCIS: Understanding and Managing Non-Invasive Breast Cancers.
Read more about the study on DCIS and invasive breast cancer.
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