Systemic Treatment of Ductal Carcinoma In Situ of the Breast

Ductal carcinoma in situ (DCIS) is a noninvasive breast cancer (BC), whose diagnosis significatively increased with the diffusion of BC screening programs. DCIS actually represents roughly 20% of new BC diagnoses (1). About 70% of DCIS shows positivity for hormone receptor (HR), while HER2 is overexpressed in 25-30% of the cases (2,3). Concerning the systemic approach, the only one that should be considered for HR-positive DCIS is adjuvant endocrine therapy (ET), according to NCCN guidelines (4). In fact, the excellent prognosis of this neoplasm does not justify the utilization of more aggressive treatment strategies, such as HER2-directed therapies or chemotherapy. Here we discuss the results of the most important clinical trials enrolling DCIS patients in the adjuvant and in the preoperative setting; in addition, we report the chemoprevention studies utilizing ET which demonstrated a reduction of the risk of DCIS development. On balance, the choice to undertake or not an adjuvant ET, which is often burdened by adverse events that could impact on the quality of life of the patients and on their adherence to the therapy, should be discussed with the patient, taking into account that no survival advantage has been demonstrated so far