Ductal Carcinoma In Situ

Abstract

Ductal carcinoma in situ (DCIS) is defined as abnormally proliferating malignant cells confined to the breast milk ducts by the basement membrane. The prognosis of DCIS with microinvasion (DCISM) is intermediate between those of DCIS and invasive ductal cancer. DCIS is diagnosed most commonly as a mammographic abnormality but can occasionally present as a palpable breast mass. Therapy for DCIS is personalized for each patient based on tumor-to-breast size ratio, mammographic appearance, margin width, and patient preference. The benefits and risks of breast-conserving surgery versus mastectomy should be discussed in detail. Overall survival after breast-conserving therapy is equivalent to mastectomy. Re-excision is recommended for positive margins and, although debated, pathologic margins less than 2 mm. For breast conservation therapy, radiation therapy is recommended to reduce the risk of local recurrence. Mastectomy is indicated in patients with persistently positive margins after attempts at breast conservation, a contraindication to radiation therapy, or diffuse, malignant-appearing calcifications or whose anxiety about local recurrence outweighs the impact of mastectomy on quality of life. Patients undergoing mastectomy for DCIS should have sentinel lymph node biopsy. Immediate breast reconstruction should be considered for patients undergoing mastectomy. Endocrine therapy such as tamoxifen is offered for 5 years to women with estrogen receptor-positive DCIS. Patients with DCIS should have annual clinical breast exams and annual mammographic imaging of all remaining breast tissue.