Ductal carcinoma begins in the milk ducts (tubes that carry breast milk from the lobules to the nipple). This is the most common breast cancer type.
- Ductal carcinoma in situ (DCIS): Cancerous cells are confined within the lining of the milk ducts, and haven't spread through the duct walls into surrounding breast tissue. If DCIS lesions are left untreated, over time cancer cells may break through the duct and spread to nearby tissue, becoming an invasive breast cancer.
- Invasive ductal carcinoma (IDC): Cancerous cells grow in the duct lining, break through the wall of the duct and invade local breast tissue. From there, the cancer may spread (metastasize) to other parts of the body.
DCIS is the most common type of noninvasive breast cancer, with about 60,000 new cases in the United States each year. About one in every five new breast cancer cases is ductal carcinoma in situ.
DCIS is divided into several subtypes, mainly according to the appearance of the tumor. These subtypes include micropapillary, papillary, solid, cribriform, and comedo.
Women with DCIS are at higher risk for having cancer return following treatment, although the chance of a recurrence is under 30 percent. Most recurrences occur within five to 10 years after the initial diagnosis, and may be invasive or noninvasive. DCIS also carries a heightened risk for developing a new breast cancer in the other breast. A recurrence of DCIS will require additional treatment.
Ductal carcinoma treatment options
The type of therapy selected may affect the likelihood of recurrence. Treating ductal carcinoma in situ with a lumpectomy (breast-conserving surgery) without radiation therapy carries a 25 – 35 percent chance of recurrence. Adding radiation therapy to the treatment decreases this risk to approximately 15 percent. Currently, the long-term survival rate for women with DCIS is nearly 100 percent.