Carcinoma In Situ


Carcinoma in situ of the breast is a precancerous condition in which certain cells in the breast have undergone malignant transformation but remain confined to a specific area and have not spread to the surrounding tissue.


Carcinoma in situ of the breast is usually present in the ducts and lobules within the breast tissue. When present in the duct, the carcinoma is known as ductal carcinoma in situ (DCIS) or intraductal carcinoma and if present in the breast lobules, it is known as lobular carcinoma in situ (LCIS). In some cases, the carcinoma may have both ductal and lobular features.


Carcinoma in situ may occur because of DNA damage that causes healthy cells to act or reproduce in an abnormal manner. Exactly how the DNA damage occurs is unclear.

Risk factors

Unmodifiable risk factors include inherited genetic mutations, old age, personal & family history of breast cancer, dense breast tissue, being Caucasian, having benign breast conditions, early menstruation (before age 12), late menopause (after age 55), and having had radiation therapy.

Lifestyle-related risk factors include alcohol consumption, being obese or overweight, an inactive lifestyle, not being pregnant or a late pregnancy, not breastfeeding, use of birth control, and being on hormone therapy.

Signs and Symptoms

Typically, carcinoma in situ does not present as a lump in the breast. However, there may be breast pain and bloody discharge from the nipple.

Cancer Stage

Breast carcinoma in situ can be classified as stage 0 breast cancer. The cancer is non-invasive and has not spread to any other tissue. It is the earliest stage of breast cancer and can even be considered as a precancerous condition.


A breast carcinoma in situ is very rarely felt by physical examination. It is often identified by mammography as tiny microcalcifications within the ducts or lobules of the breast. A confirmation of the diagnosis is performed by biopsy of the suspicious area of the breast.


If left untreated, breast carcinoma in situ may spread to the surrounding tissues and other organs of the body, resulting in fatal consequences.


The most common treatments for breast carcinoma in situ include:

  • Lumpectomy (surgical removal of the suspicious area of the breast)
  • Lumpectomy and radiation therapy
  • Mastectomy (surgical removal of the entire breast)
  • Surgery and hormonal therapy.