[Ductal carcinoma in situ in 2019: Diagnosis, treatment, prognosis]

Ductal carcinoma in situ (DCIS) currently represents up to 15% of the newly diagnosed breast cancers, and are almost always detected by microcalcifications. Global prognosis is good (3% of 15-year specific mortality) but invasive local recurrences (LR) can lead to metastasis in 12-15% of the cases. Breast conserving surgery with whole breast irradiation is the main treatment (reducing LR by 50%), but mastectomy (with or without reconstruction) is performed in about 30% of the cases due to wide lesion size and/or multicentricity. The role of tamoxifen remains unclear. Axillary dissection is needless but sentinel node biopsy is proposed in case of micro-invasion suspicion (large lesions with high grade). The main factors of LR are young age (≤40 years) incomplete excision, and high nuclear grade with comedonecrosis. Several studies on "therapeutic descalation" are still ongoing in order to identify the "low risk" DCIS (about 10% of the cases) in which radiotherapy could be safely omitted.