The big picture of pre-invasive breast neoplasms

Abstract

Current standard treatment of ductal carcinoma in situ (DCIS) is complete surgical removal, by mastectomy or wide excision followed by radiation. Due to increased breast cancer awareness and the use of screening mammograms, the incidence of DCIS has increased substantially over the last few decades. However, the increased detection and treatment of DCIS (Removal of 50 000 to 60 000 DCIS annually in the United States) have not resulted in a drop in breast cancer incidence. Researchers have therefore started to question if DCIS has been over-treated. With better understanding of DCIS, we now tend to recognize DCIS as a spectrum of disease instead of a single disease entity. The lessons learned about the biology of DCIS over the years have enabled us to understand this complex disease better, including the heterogenenity and variation in clinical behaviours of DCIS. This thesis reviewed and studied the clinical and pathological characteristics of DCIS, as well as other premalignant breast neoplasms, aiming to provide a clearer picture of the entire pre-malignant breast neoplasm disease spectrum. Association between atypical ductal hyperplasia and DCIS will be reviewed; long-term survival of DCIS will be evaluated based on the database from a territory-wide cancer registry. Ultimately, we aim to translate our clinical research into clinical practice by evaluating the feasibility of personalizing treatment for low-risk DCIS patients.