Ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) literally means groups of "cancerous" epithelial cells which remain in their normal location (in situ) within the ducts and lobules of the mammary gland. Clinically, DCIS is considered to be a premalignant (i.e. potentially malignant) condition, because the biologically abnormal cells have not yet crossed the basement membrane to invade the surrounding tissue. When multiple lesions (known as "foci" of DCIS) are present in different quadrants of the breast, this is referred to as "multicentric" disease. When classified as a cancer, it is referred to as a "non-invasive" or "pre-invasive" form. It is described by the National Cancer Institute as a "noninvasive condition". ==Signs and symptoms==

Most of the women who develop DCIS do not experience any symptoms. The majority of cases (80-85%) are detected through screening mammography. The first signs and symptoms may appear if the cancer advances. Because of the lack of early symptoms, DCIS is most often detected at screening mammography. In a few cases, DCIS may cause: • A lump or thickening in or near the breast or under the arm • A change in the size or shape of the breast • Nipple discharge or nipple tenderness; the nipple may also be inverted, or pulled back into the breast • Ridges or pitting of the breast; the skin may look like the skin of an orange • A change in the way the skin of the breast, areola, or nipple looks or feels such as warmth, swelling, redness or scaliness. ==Causes==

The specific causes of DCIS are still unknown. The risk factors for developing this condition are similar to those for invasive breast cancer. Some women are however more prone than others to developing DCIS. Women considered at higher risks are those who have a family history of breast cancer, those who have had their periods at an early age or who have had a late menopause. Also, women who have never had children or had them late in life are also more likely to get this condition. Long-term use of estrogen-progestin hormone replacement therapy (HRT) for more than five years after menopause, genetic mutations (BRCA1 or BRCA2 genes), atypical hyperplasia, as well as radiation exposure or exposure to certain chemicals may also contribute in the development of the condition. Nonetheless, the risk of developing noninvasive cancer increases with age and it is higher in women older than 45 years. ==Diagnosis==

80% of cases in the United States are detected by mammography screening. More definitive diagnosis is made by breast biopsy for histopathology. File:Mammogram microcalcifications in carcinoma in situ, CC, details.png|Mammogram microcalcifications in ductal carcinoma in situ File:Histopathology of dystrophic microcalcifications in ductal carcinoma in situ.jpg|Histopathology of dystrophic microcalcifications in DCIS, H&E stain. File:Histopathologic architectural patterns of DCIS.png|Histopathologic architectural patterns of DCIS. File:Histopathology of high-grade DCIS.png|Histopathology of high-grade DCIS. H&E stain.RBC = red blood cell. File:Histopathology of microinvasive ductal carcinoma in situ.png|DCIS with microinvasion, defined as focus of invasive cancer measuring up to 1.0 mm in size. File:Immunohistochemistry with calponin in ductal carcinoma in situ.jpg|Immunohistochemistry for calponin in ductal carcinoma in situ, highlighting myoepithelial cells around all tumor cells, thereby ruling out invasive ductal carcinoma. File:Histopathology of ductal carcinoma in situ with comedo necrosis.jpg|Ductal carcinoma in situ with comedo necrosis spanning 30% of its diameter, which is generally regarded as the minimal size to classify it as comedo. ==Treatment==

There are different opinions on the best treatment of DCIS. Surgical removal, with or without additional radiation therapy or tamoxifen, is the recommended treatment for DCIS by the National Cancer Institute. Surgery may be either a breast-conserving lumpectomy or a mastectomy (complete or partial removal of the affected breast). If a lumpectomy is used it is often combined with radiation therapy. Chemotherapy is not needed for DCIS since the disease is noninvasive. While surgery reduces the risk of subsequent cancer, many people never develop cancer even without treatment and the associated side effects. The Cochrane review did not find any evidence that the radiation therapy had any long-term toxic effects. Mastectomy There is no evidence that mastectomy decreases the risk of death over a lumpectomy. Mastectomies remain a common recommendation in those with persistent microscopic involvement of margins after local excision or with a diagnosis of DCIS and evidence of suspicious, diffuse microcalcifications. Sentinel node biopsy Some institutions that have encountered high rates of recurrent invasive cancers after mastectomy for DCIS have endorsed routine sentinel node biopsy (SNB). However, research indicates that sentinel node biopsy has risks that outweigh the benefits for most women with DCIS. SNB should be considered with tissue diagnosis of high-risk DCIS (grade III with palpable mass or larger size on imaging) as well as in people undergoing mastectomy after a core or excisional biopsy diagnosis of DCIS. ==Prognosis==

With treatment, the prognosis is excellent, with greater than 97% long-term survival. If untreated, DCIS progresses to invasive cancer in roughly one-third of cases, usually in the same breast and quadrant as the earlier DCIS. About 2% of women who are diagnosed with this condition and treated died within 10 years. ==Epidemiology==

DCIS is often detected with mammographies but can rarely be felt. With the increasing use of screening mammography, noninvasive cancers are more frequently diagnosed and now constitute 15% to 20% of all breast cancers. In 2009 about 62,000 cases were diagnosed. ==References==