Ductal carcinoma in situ (DCIS) is an early form of breast cancer.

Breast anatomy

Breasts are made up of milk producing glands called lobules that secrete milk that passes out of the nipple via tubes called ducts. These ducts are further surrounded by fatty and fibrous tissues.

Breast cancer and DCIS

Breast cancer begins when the cells in the ducts divide uncontrollably and DCIS is an early form of breast cancer where cancer affects only the milk ducts and not the surrounding tissues. This is referred to as localized or "in situ" cancer. DCIS also does not have the capacity to spread to other parts of the breast or the rest of the body. Due to these features, DCIS is also termed pre-invasive cancer or non-invasive cancer. Sometimes DCIS is also referred to as intraductal cancer, since it remains confined within the ducts.

Symptoms of DCIS

DCIS can affect both men and women, although it is much rarer in men than in women. Most people with DCIS have little or no symptoms but some may develop a lump or a slight discharge from the nipple. There may also be a rash around the nipple called Paget's disease.

Diagnosis of DCIS

Since there are no overt symptoms of DCIS, diagnosis is rarely made in the early stages. The cancer may be detected on routine mammograms that are recommended for peri and post menopausal women and DCIS has become more commonly detected since the introduction of such screening. Around 20% of all cancers detected by mammograms are found to be DCIS. For people who do present with a lump or nipple discharge, other methods of diagnosis may be applied such as an ultrasound scan, a core biopsy or fine needle aspiration biopsy.

Once the sample has been taken from the breast, it can be stained with special dyes and examined under the microscope. The type of cancer is graded depending on the appearance of the cells and may be categorized as high, intermediate or low grade DCIS.

Treatment of DCIS

The aim of DCIS treatment is to remove the whole cancer from the breast tissue, which should either almost or entirely remove the risk of recurrence. Types of treatment of DCIS include:

• Surgery - This is the most commonly recommended treatment for DCIS and includes removal of the entire cancer. A wide local lumpectomy or wide local excision called breast-conserving surgery is the first choice of treatment. A sample of lymph node may also be removed from the axilla or arm pit in order to check for lymph node involvement.
• Adjuvant (additional) treatment - This includes radiotherapy and in some cases hormone therapy. Chemotherapy is usually not applicable or useful in patients with DCIS. Radiation therapy may be used after surgery to clear up any remaining cancer cells.