As with other forms of cancer therapy, one of the areas in which we fall short is having an accurate way to determine who will benefit from a specific therapy. We can only refer to data for large numbers of people with similar criteria. No one can say, in an individual case, whether a given treatment is critical or what the outcome would be without it. DCIS is even more frustrating: there are gradations, meaning specific characteristics which, when found, indicate a higher chance of recurrance with local removal alone. For example, "comedo" variety, in which the malignant cells are packed in a duct like toothpaste. In that case, it's pretty clear radiation is of value; on the other hand, since it's still non-invasive, many women with it, especially if it's not real extensive, would be cured with excision alone. So, you need to be told the exact details of the nature of your personal DCIS, and ask what the data are for recurrance with and without radiation. Then, you'll have to decide, knowing that with any type, there are women who will do better with radiation, and women who would be ok without it, and that there's no way to say for a particular person. Some day, some day.....we'll get there.
Dear fooddiva, Mastectomy had been the standard treatment of DCIS for a number of years. Breast conservation surgery (BCS)has gained acceptance as treatment of DCIS based on the success it had with invasive breast cancers. When BCS is used, radiation therapy is often a part of the treatment plan based on results of the National Surgical Adjuvant Breast Project [NSABP] B-17 trial, because the prevalence of noninvasive breast cancer (DCIS) in the same breast, was reduced from 13.4% to 8.2% and, for invasive cancer, from 13.4% to 3.9%, after using radiation therapy. Some factors may decrease the decision to give radiation therapy - such as: what the tumor looks like under the microscope (having favorable features), having a good margin around the DCIS, or no remaining calcifications after surgery. So the information from the surgery will all be put together in order to help to make the decision as to whether or not radiation therapy will be of benefit to the individual.
The use of hormone therapy (tamoxifen)after surgery for DCIS has been shown to decrease the incidence of invasive breast cancer.