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Home What is Breast Cancer Types of Breast Cancer Noninvasive Breast Cancer/Breast Carcinoma in Situ

Noninvasive Breast Cancer/Breast Carcinoma in Situ

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Breast carcinoma in situ is a heterogeneous group of lesions that can vary greatly in terms of behavior and risk of progression. Studies have shown that approximately one-third of patients with carcinoma in situ of the breast will eventually develop invasive cancer.[1]


The term “carcinoma in situ” indicates that these are non-invasive conditions; more specifically, these are abnormal cells but they do not infiltrate the surrounding tissues. There are two main types of breast carcinoma in situ: Lobular Carcinoma in Situ (LCIS) and Ductal Carcinoma in Situ (DCIS). The terms “lobular” and “ductal” indicate the location of these abnormal cells within the breast. LCIS, sometimes called “Stage 0 breast cancer”, occurs when abnormal cells accumulate in the milk-producing areas of the breast (the lobules). DCIS occurs when the abnormal cells accumulate in the milk ducts.


LCIS and DCIS are associated with an increased risk of developing invasive cancer. LCIS is considered a risk factor rather than a direct precursor of breast cancer. Patients with LCIS are 7-12 times more likely than the general population to develop invasive breast cancer.[2] In patients with LCIS, invasive disease can occur in either breast; there is an 18% risk of developing cancer in the same (unilateral) breast and a 14% risk for the opposite (contralateral) breast.[3] On the other hand, DCIS is thought of as a direct precursor of invasive breast cancer. As such, DCIS indicates higher risk of invasive disease in the unilateral breast.


The number of cases of DCIS diagnosed in the U.S. has increased due to increased screening mammograms. Micro-calcification can often be seen on these scans. A palpable breast mass is often not present, which further supports the importance of screening mammograms. Unlike with DCIS, LCIS is not visible on mammogram. LCIS is also often asymptomatic and discovered by chance. A definitive diagnosis depends on microscopic investigation of the cells after biopsy.


Treatment depends on the lobular or ductal location of the abnormal cells. In LCIS, because the lesion is not considered a direct precursor to cancer, standard management is surveillance. Another option is mastectomy, which has been shown to be prophylactic (reduces the risk of developing breast cancer in the future), particularly for patients with a family history of breast cancer or other risk factors. In DCIS, because the lesion is considered an anatomic precursor, lumpectomy with breast irradiation is often used. Other treatment options for LCIS and DCIS include hormone drugs such as tamoxifen and raloxifene. These drugs work by opposing the receptor for the hormone that encourages breast cell growth (estrogen). However, like with all diseases, treatment options vary from person-to-person, case-to-case.

Stephanie Wu, Shikha Jain MD



[1] Ottesen GL. Carcinoma in situ of the female breast. A clinico-pathological, immunohistological, and DNA ploidy study. APMIS Suppl. 2003;(108):1-67.

[2] Sakorafas GH, Krespis E, Pavlakis G. Risk estimation for breast cancer development; a clinical perspective. Surg Oncol. 2002 May;10(4):183-92.


[3] Fentiman IS. The dilemma of in situ carcinoma of the breast. International journal of clinical practice, 2001 Dec; 55(10): 680-3.