Can we know what to do when DCIS is diagnosed?

Utilizing routine histopathologic parameters obtained from appropriately handled lumpectomy and mastectomy specimens, a rational therapeutic plan based on epidemiologic and outcome-based data can be devised for any patient diagnosed with ductal carcinoma in situ (DCIS). In order to make a sound decision when weighing the current treatment options for DCIS--which include excision alone, excision plus radiation, and mastectomy--the following are mandatory: 1) assurance of an accurate diagnosis, 2) assessment of DCIS size and grade, and 3) careful margin evaluation. Accurate grading of DCIS is critical, since high nuclear grade and the presence of necrosis are highly predictive of the inability to achieve adequate margins, of local recurrence, and of the probability of missed areas of invasion. Margin status is the single most important determinant of local control following breast conservation for DCIS; numerous studies have shown that as the margin width increases, the risk of local failure decreases. The pros and cons of irradiating conservatively treated patients with DCIS should be carefully weighed on a case-by-case basis. Despite the 20-year-old dogma that all patients treated with breast conservation should receive postoperative radiation, a subset of patients who can be successfully treated by excision alone has been identified.