DUCTAL CARCINOMA IN-SITU .1. DEFINITION AND DIAGNOSIS

The frequency of diagnosis of ductal carcinoma in situ (DCIS) has incr eased in Australia, largely because of the national screening programm e. Ductal carcinoma in situ presents a dilemma because of problems wit h its diagnosis and variations in reporting pathological and radiologi cal findings, making it difficult to define optimal treatment and comm unicate information in a way that helps the patient understand the pro blems and make decisions. There is considerable inter-observer variati on, particularly in differentiating low-grade DCIS from ductal hyperpl asia, with or without atypia, but pathologists who participate in regu lar pathological review sessions vary less in their opinions. Mammogra phy remains the main investigative tool for DCIS and the American Coll ege of Radiology has recommended standardized reports. A team approach is required for the removal and diagnosis of possible DCIS, Although the team may be best co-located in the one facility, this is not pract ical in many community hospital settings which lack on-site radiology and pathology services. The decision about how much breast tissue to r emove will need to be made for each patient and depends on the size of the microcalcification and how suspicious the mammogram is for DCIS. We recommend the use of synoptic reports for DCIS, and we document the minimum factors that should be reported by pathologists. The evaluati on and management of DCIS by a multidisciplinary team will allow the p atient access to information required to make often difficult treatmen t decisions. In this paper, we review the literature about the natural history, pathology, cytology and radiology of DCIS and document the 2 0 critical steps required for the diagnosis of impalpable, mammographi c microcalcifications suspected to be DCIS.