What is ductal carcinoma in situ (DCIS)?

Related conditions:
Breast cancer, Paget disease of the nipple

Definition:



Ductal carcinoma in situ (DCIS) is a noninvasive form of breast cancer occurring in the ducts that are responsible for secreting milk. It is the most common type of noninvasive breast cancer, and because it is nonmetastatic, most patients survive their disease.

Risk factors: Reproductive risk factors include women who never had a full-term pregnancy, had their first pregnancy after age thirty, started menstruation early, or had a late menopause. The use of oral contraceptives and postmenopausal estrogen-progestin replacement therapy (more than five years) has been shown to increase the risk of breast cancer. Having a family history of early-onset or bilateral disease and carrying the breast cancer susceptibility gene
BRCA1
or BRCA2 increase the risks as well. Breast cancer risk increases with age, with most cases occurring in women over the age of sixty. The following are factors that reduce the risk of breast cancer: physical activity (exercise), multiple pregnancies, breast-feeding, and early removal of both ovaries.

Etiology and the disease process: Not all DCIS lesions become invasive breast cancer, but most invasive lesions are preceded by DCIS. Most of the genetic changes present in invasive breast cancer are already present in DCIS, suggesting that if left untreated, these tumors would indeed become invasive.

Incidence: The National Cancer Institute estimated in 2012 that one out of every eight women born would be diagnosed with breast cancer at some time in their lives. The American Cancer Society claimed that in 2012, DCIS was the most common type of breast cancer, representing 25–30 percent of all newly diagnosed cases. According to Siegel in the journal CA, more than 90 percent of all DCIS cases in 2011 were diagnosed by mammography. In 2013, the American Cancer Society estimated that approximately 60,000 new US cases of DCIS were diagnosed annually, which accounted for approximately 1 out of every 5 new breast cancer cases. The use of digital mammography and MRIs (magnetic resonance imaging) has greatly increased the detection and diagnosis of DCIS and therefore the number of new cases reported. New technology has also lead to an increased rate of survival for those women whose lesions are detected early.

Symptoms: Most breast cancers do not cause any pain, making them hard to detect. However, any change in the size or shape of the breast, change in the look or feel of the breast or nipple, or any lump or thickening in or near the breast or underarm area may be a symptom of breast cancer. Other more obvious changes include nipple discharge, tenderness, an inverted nipple, and ridges in or pitting of the breast (when the skin looks like that of an orange).

Screening and diagnosis: Because this disease can remain symptomless, monthly self-examination of the breasts after the age of twenty, yearly checkups, and regular mammographies after the age of forty are crucial to early detection. Most of the new cases of DCIS detected by mammography are not detectable by examination alone.

Once DCIS is detected, tissue is sampled using fine needle aspiration (FNA) biopsy or core needle biopsy. According to the standard staging system, DCIS is a Stage 0 breast cancer. Pathologic analysis will determine the classification of the tumor, its size and margins, and if the tumor is hormone dependent. These criteria are then further classified as follows:

• Grade I (low grade): Non-high grade without necrosis (the tumor cells look similar to normal cells, and the tumor may be solid, cribriform, or papillary)





• Grade II (medium grade): Non-high grade with necrosis





• Grade III (high grade): Very quickly growing tumor with the cells in the center of the duct becoming starved from the blood supply; described as “comedo”

Treatment and therapy: Treatment will vary from case to case depending on the size and grade of the tumor and whether there is a family history of breast cancer. Typically, once diagnosis is confirmed, a lumpectomy is performed to remove the entire area of the DCIS and a marginal area of normal breast tissue around it. This is followed by radiation to the whole breast to kill cancer cells outside the surgical margin and to reduce the risk of the cancer coming back. In some cases a mastectomy, in which the entire breast is removed, may be recommended if the DCIS covers a very large area or multiple areas of the breast or if the patient has a family history of breast cancer or a known gene abnormality (BRCA1 or BRCA2). Because this type of cancer has not invaded into the normal tissue, chemotherapy is not needed for DCIS. If the tumor tests positive for hormone receptors, hormonal therapy (tamoxifen and aromatase inhibitors) can be used to lower the risk of recurrence.

Prognosis, prevention, and outcomes: Because DCIS is a precancerous or preinvasive lesion, the prognosis is very good. Less than 1 percent will die from this disease. It is possible that an invasive focus not found at the time of diagnosis will later develop into metastatic disease, but the likelihood is small. About 40 to 50 percent of local recurrences are invasive and 10 to 20 percent of patients will develop metastases and die from their disease. The more aggressive the therapy, the lower the rate of mortality. Additional treatment, including surgery, radiation therapy, antiestrogen therapy, or a combination of these, will reduce the chances of recurrence of the disease.

Bibliography

"Breast Cancer." American Cancer Society. Amer. Cancer Soc., 2014. Web. 27 Aug. 2014.

Hunt, Kelly K., Geoffrey L. Robb, Eric A. Strom, and Naoto T. Ueno. Breast Cancer. M. D. Anderson Cancer Care Series. New York: Springer, 2001. Print.

Link, John. Breast Cancer Survival Manual: A Step-by-Step Guide for the Woman with Newly Diagnosed Breast Cancer. 5th ed. New York: Holt, 2012. Print.

Mulcahy, Nick. "In US, Even More DCIS is Coming: What Should Be Done?" Medscape. WebMD, 12 Mar. 2013. Web. 19 Sept. 2014.

Newman, Lisa A., and Jessica M. Bensenhaver, eds. Ductal Carcinoma In Situ and Microinvasive/Borderline Breast Cancer. New York: Springer, 2014. Print.

“The Picture Problem: Mammography, Air Power, and the Limits of Looking.” The New Yorker, December 13, 2004. http://www.gladwell.com/2004/2004_12_13_a_ picture.html.

Roses, Daniel F. Breast Cancer. Philadelphia: Elsevier, 2005. Print.

Shockney, Lille D. Navigating Breast Cancer: A Guide for the Newly Diagnosed. Sudbury: Jones & Bartlett, 2006. Print.

Siegel, R., et al. "Cancer Statistics, 2011: The Impact of Eliminating Socioeconomic and Racial Disparities on Premature Cancer Deaths." CA: A Cancer Jour. for Clinicians 61.4 (2011): 212–36. Print.

Virnig, B. A., et al. "Ductal Carcinoma In Situ of the Breast: A Systematic Review of Incidence, Treatment, and Outcomes." Jour. Natl. Cancer Inst. 102 (2010): 170. Print.