CHICAGO--Despite an overall trend toward breast conservation, many breast cancer authorities believe that ductal carcinoma in situ (DCIS) too often is treated by mastectomy, and that axillary dissection and irradiation frequently are performed unnecessarily.
In order to make the "punishment fit the crime," physicians treating DCIS need to balance the extent of surgery and the application of irradiation with a number of factors, William Wood, MD, said at the 50th Cancer Symposium of the Society for Surgical Oncology. These include not only tumor size and margins, but also tumor grade and the patient's age.
Since DCIS can develop into invasive disease, "we can't take it too lightly," said Dr. Wood, professor and chairman of the Department of Surgery, Emory University School of Medicine. However, he said, a formal treatment algorithm for DCIS "requires thoughtful application based upon the number of years a woman would be at risk, the likely biology of the tumor, and its extent."
The algorithm presented by Dr. Wood involves surgical excision of the DCIS with a relatively small resection margin for biopsy; magnification view mammog-raphy to make sure there is no stream of DCIS moving toward the nipple or areola or going off elsewhere in the breast; and detailed pathologic evaluation.
DCIS that has a 1- to 4-mm focus and 5- to 10-mm margin would be observed after excision, according to this algorithm. "I would do nothing else; I think any additional treatment is likely to be overtreatment," Dr. Wood said.
For DCIS with a 5- to 20-mm focus and 5-mm to 10-mm margin, Dr. Wood would add irradiation. Lumpectomy and radiation therapy would also be appropriate for more than 20 mm of tumor as long as a 10-mm clear margin could be obtained and the breast could be preserved in appearance.
The algorithm calls for more extensive treatment of a comedo or high-grade tumor, particularly in a young patient. Less extensive treatment would be indicated "in an older patient where a low-grade disease might never become an event in her lifetime," he said.