Ductal carcinoma in situ (DCIS) is the earliest form of breast cancer, found only within the milk duct in which the cancer started. DCIS is not life-threatening. Doctors sometimes refer to DCIS as precancerous because it is non-invasive. This means that at the time of diagnosis of DCIS, the cancer cells appear to have not yet figured out how to spread outside the duct or to other areas of the body. DCIS is also referred to as Stage 0 breast cancer.
DCIS is associated with an increased risk of getting an invasive cancer, or cancer that spreads to surrounding tissues, in the future. The risk of DCIS coming back is extremely variable and depends on the size and “personality” of the DCIS, as well as the type of treatment. Doctors use the terms high-grade and non-high-grade to describe the “personality” of DCIS. High-grade DCIS poses a greater risk for future problems. Recurrence of cancer can be either non-invasive (not life-threatening) or invasive (potentially serious).
As you might imagine, DCIS can be small and hard to see on a routine screening mammogram. It usually cannot be felt with breast self-exam (BSE). Even when DCIS is identified, the “personality” (high-grade or not) may not be obvious with a mammogram. The research reported in this story showed that MRI was better than mammography at finding DCIS, and particularly better at finding riskier high-grade DCIS. MRI uses magnetic fields to highlight different kinds of tissues, both normal and abnormal. The results of this study add to other studies that have shown that MRI can, in some circumstances, perform better than routine mammograms in screening for breast cancer. The American Cancer Society recently recommended the use of MRI for screening instead of mammography in certain women at high risk for breast cancer. This does not mean that screening mammograms will be replaced by MRI. But your doctor may decide that in your particular circumstance an MRI should be done instead of, or in addition to, a mammogram.
The main goal of treating DCIS is to reduce the risk of an invasive cancer later on. So in most cases, the treatment for DCIS is breast-conserving surgery (such as lumpectomy). To substantially lower the risk of developing an invasive cancer, most doctors recommend additional treatment with radiation after surgery for DCIS. Treatment recommendations will depend in part on whether the DCIS is high-grade or not. Women with hormone-receptor-positive DCIS may also decide with their doctors that they will have hormonal treatment after surgery to reduce the risk of recurrence and to lower the risk of getting a new cancer. To learn more about DCIS, visit the DCIS – Ductal Carcinoma in Situ section.
This article was made possible by an educational grant from GlaxoSmithKline.
CHICAGO (Reuters Health) - Magnetic resonance imaging (MRI) seems to be much more sensitive than mammography in diagnosing ductal carcinoma in situ (DCIS) in general, and aggressive, high-grade DCIS in particular, according to the results of a large study presented at the annual meeting of the American Society of Clinical Oncology.
DCIS is a noninvasive, precancerous condition that can progress to invasive cancer if untreated. DCIS can be any one of a wide variety of pathological tissues that are classified into subtypes based largely on their appearance. Some subtypes appear to be "high-grade," or more aggressive, and have a greater chance of being invasive.
Compared with mammography, MRI doubled the overall sensitivity of detecting DCIS and doubled the sensitivity of diagnosing high-grade DCIS as well, reported Dr. Christiane K. Kuhl, vice chairman and professor of radiology at the University of Bonn, Germany.
"High-grade DCIS is important to diagnose" because it can be easily cured with surgery, noted Kuhl. However, "if left untreated, it will progress to high-grade invasive cancer."
Kuhl and colleagues investigated the sensitivity of high-resolution MRI and state-of-the-art mammography for diagnosing DCIS. Among more than 5,000 women in the study, 167 had a confirmed diagnosis of DCIS.
MRI was positive for 153 of 167 of these women (92 percent), while mammography was positive for only 93 of 167 (56 percent). "This difference is statistically significant at a very high level," Kuhl said.
MRI also identified 98 percent of the high-grade DCIS, whereas mammography identified only 52 percent of the high-grade DCIS.
MRI identified 85 percent of non-high-grade DCIS and mammography spotted 61 percent of non-high grade DCIS.
"Mammography was less sensitive for high-grade versus non-high-grade DCIS," Kuhl pointed out.
Of the 72 DCIS that were only detected by MRI, 69 percent were high grade and 31 percent were non-high-grade. Of the 12 DCIS only detected by mammography, 17 percent were high-grade and 83 percent were non-high-grade.
Dr. Julie Gralow, of the University of Washington and moderator of the press briefing, commented: "There is a lot of controversy over treatment of low-grade DCIS in this country...so this study showing that the highest-grade DCIS is what is most commonly found on MRI and actually missed in a good number of mammograms is really key, and I think will help us pick out which cancers really need some intervention and which might not."
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