What is Ductal Carcinoma in Situ?
Ductal carcinoma in situ (DCIS) is the first stage of abnormal cell growth (carcinoma) that is confined (in situ) within a milk duct of the breast. There is no local or distant cancer cell invasion and it may or may not be detected by physical examination alone.
Women who are at risk for DCIS cancer are older women, those who have a family history of breast cancer, those who have a history of benign breast lumps, women who have never been pregnant or who had a late pregnancy in their 30s and those who used hormone replacement treatment after menopause.
The cause of DCIS is not certain, but factors that are associated with its development are gene mutation, environmental exposure to carcinogenic chemicals and radiation, hormonal exposure (estrogen and progestin) and lifestyle factors like alcohol consumption and red meat ingestion.
How is Ductal Carcinoma in Situ Detected?
Many women with DCIS do not detect any symptoms. However, some may notice breast cancer symptoms like a breast lump or a nipple discharge.
Physical examination may reveal a palpable lump but in many cases even physicians cannot find a very small lump embedded in the tissues of large breasts.
The National Cancer Institute reports that DCIS cancer is usually (around 80 percent) first found by a routine mammogram which is an imaging test that detects small calcifications in the breast. They appear as tiny, white and irregularly shaped spots. The radiologist may then recommend a diagnostic mammogram which takes images under higher magnification from more angles. An ultrasound may also be requested. Finally, a biopsy of the breast tissue may be needed to confirm the diagnosis.
The biopsy of ductal carcinoma may be taken by a needle and/or from a wide incision of the breast (lumpectomy). The cell samples are analyzed by a pathologist for grade and cell structure. This analysis will reveal whether there are a large number of abnormal cells that are rapidly multiplying and if there are signs of degeneration. These are signs that may indicate that even if the malignancy is confined to milk ducts at the moment they may later become aggressive and invade the rest of the breast and other organs. Furthermore, women who are found to have DCIS have a greater chance for cancer recurrences five to ten years after initial diagnosis than those who have never had cancer before.
For these reasons annual mammography is being recommended for women above 50 years old who may be at risk for breast cancer. More and more Americans are being diagnosed with early stages of breast cancer owing to routine mammograms being done and improvement in the technology. These are important to ensure early treatment and prevention of cancer spread.
Treatment of DCIS
Early management of ductal carcinoma consists of these treatment options:
- Lumpectomy or breast-conserving surgery to remove the lump while saving most of the breast, followed by radiation therapy – radiation decreases the chances for recurrence of cancer
- Lumpectomy alone – for women who are at low risk and the DCIS is small. Close follow-up is recommended because recurrences are common.
- Mastectomy or surgical removal of a breast is done in some cases, especially if the DCIS covers a large area or if there is a strong family history of breast cancer.
- Hormone therapy to reduce estrogen levels in patients who are found positive for hormone receptors – such as Tamoxifen (Nolvadex) and aromatase inhibitors such as Arimidex (anastrozole), Femara (letrozole) and Aromasin (exemestane)
Chemotherapy is not needed in patients with localized tumors. It is usually reserved for those whose cancer has spread to distant sites such as the liver, lungs and brain.
Treatment generally depends on the size of the tumor and the risk factors for each patient so the choice should be individualized. Results of early treatment are generally good, such that complete removal of the tumor usually prevents recurrence.
Women will benefit from education about breast cancer which is a very common malignancy that leads to many deaths. It is also important to emphasize that early detection and treatment with careful follow-up of ductal carcinoma are essential in preventing recurrence or progression to advanced stages.
Mayo Clinic, “Ductal carcinoma in situ (DCIS)”, https://www.mayoclinic.com/health/dcis/DS00983
BreastCancer.org, “DCIS – Ductal Carcinoma In Situ”, https://www.breastcancer.org/symptoms/types/dcis/