Pathology of preinvasive and excellent-prognosis breast cancer

Little has been added in the past year to our knowledge of the premalignant lesions that have implications of increased subsequent cancer risk. However, studies of molecular biologic associations of these lesions are proceeding. The heterogeneous nature of ductal carcinoma in situ and its clinical implications continues to evolve. Several studies of ductal carcinoma in situ have confirmed that this entity extends in continuity within the breast whether associated with invasive carcinoma or not. Therapeutic stratification of ductal carcinoma in situ lesions depending on their grade and size is widely accepted, however, formal larger cooperative studies are necessary. Therapeutic use of histologic grading and recognizing special histologic subtypes continues to gain importance. Studies detailing the the use of grading as an additive measure of the predictiveness of staging, as well as documentation of interobserver agreement when fostered by rule-structured agreement, dominate the current literature on this subject. The use of stereotactically guided needle biopsy is rapidly gaining a broad consensus. Precise guidelines for management of borderline diagnoses are under development.