Ductal carcinoma in situ (DCIS) is a stage 0 breast cancer, meaning breast cancer in its earliest stage. "In situ" means that the cancer is situated within the tissue where cancer cells developed and has not spread to the neighboring tissues or other organs inside the body. This cancer is usually confined to the lining of milk ducts of the breast; however, it generally has a tendency to become invasive. The majority of ductal carcinoma in situ cases occur in women, but it can also develop in men.
Most ductal carcinoma in situ are detected during mammogram screenings. A mammogram is a procedure where the breast is compressed between plates to take an x-ray picture of the tissue. A radiologist, the doctor who interprets the mammogram results, looks for white spots called microcalcifications or flecks of calcium deposits. The presence of microcalcifications are frequently indicative of abnormal changes in the breast. Further evaluation, such as an excision biopsy, where the lump is removed surgically and processed in the laboratory, would then be needed for confirmation of the presence of ductal carcinoma in situ.
Many women diagnosed with ductal carcinoma in situ do not have any symptoms. Others may feel the presence of a lump or multiple lumps in the breast, or some nipple discharge during a breast examination. The detection of the cancer in its earliest stage often can prevent it from invading neighboring tissues and distant organs, like the lungs and bones.
There are many factors which may cause the development of ductal carcinoma in situ. These include a history of breast cancer in the family, hormone exposure, and lifestyle factors such as alcohol consumption, obesity, and lack of exercise. Other risk factors for DCIS are age, as it usually affects women 40 years old and older, and having never been pregnant or having had a first pregnancy after 30 years of age.
Treatment for ductal carcinoma in situ may include a mastectomy or a breast conserving therapy and radiation, depending on the need of the patient. In a simple mastectomy, the whole breast and some lymph nodes are usually removed. For the breast conserving therapy, only the lump is removed, together with some of the surrounding tissue, and is often followed by radiation. Both procedures are done to prevent ductal carcinoma in situ from progressing into an invasive cancer, which usually has a poor outcome.