Question: Four weeks ago I had a core biopsy with ductal carcinoma in situ and recently had a lumpectomy. My doctor said there was 2.2 cm of DCIS, high grade with necrosis, margins negative, estrogen receptor negative. He is suggesting radiation therapy but when I went for a second opinion, the pathologist said the margins were close and I needed a re-excision before radiotherapy. How can one doctor call the margin negative and another say I need more surgery? I do not want more surgery at this point.

Answer: I can understand your confusion. Unfortunately, there is no uniformly agreed upon definition of a negative margin for ductal carcinoma in situ. Some feel that as long as the carcinoma is not transected at the ink it is a negative margin (this was the definition used in early NSABP studies on ductal carcinoma in situ). I do not believe in simply saying the margins are negative or positive–I give measurements of the tumor distance from each margin that the surgeon designated. Many other pathologists do this as well; however, we have not agreed upon how many millimeters is “ok” and do not require re-excision.  That being said, I am glad you sought out a second opinion as it clearly has pointed out a discrepancy in the status of your lumpectomy margins which could impact your further treatment. More research in this area needs to be done to help patients and their doctors feel more comfortable about what margins are “safe” and do not need re-excision vs. those that need more surgery. I wish I could give you a more definitive answer at this point. Perhaps getting a copy of your pathology report and going over it with your surgeon (with particular reference to the actual margin distance) would help you make your decision.