Ductal carcinoma is cancer that starts in the milk ducts of the breast. The disease can be either ductal carcinoma in situ, or DCIS, which is the earliest stage of breast cancer and highly treatable; or invasive ductal carcinoma, which invades other tissues, according to WebMD.
More than half of breast cancer patients are diagnosed with ductal carcinoma, notes WebMD. One out of five new breast cancer diagnoses is categorized as DCIS, an uncontrolled growth of cells known as Stage 0 cancer. Although the great majority of DCIS patients are cured, treatment is advised because the condition is considered precancerous with 25 to 50 percent of DCIS patients developing invasive breast cancer within 10 years. Invasive ductal carcinoma is a cancer that grows through the walls of the duct and into the surrounding breast tissue and can metastasize to other areas of the body.
Both types of ductal carcinoma are detected by manual breast exam or mammography. Both can be treated with lumpectomy to remove only the cancerous material. With DCIS, surgery may be followed by radiation therapy. Invasive breast cancer may call for mastectomy and follow-up treatment with chemotherapy, endocrine therapy, radiation or a combination of all three, according to WebMD.