This page was reviewed under our medical and editorial policy by
Daniel Liu, MD, Plastic and Reconstructive Surgeon
This page was reviewed on February 18, 2022.
After skin cancer, breast cancer is the most common type of cancer diagnosed in women. About 313,720 cases will be diagnosed in 2024, according to the American Cancer Society (ACS). Men also may develop breast cancer, though it’s much more rare.
Breast cancer is classified into different types based on how the cells look under a microscope. Most breast cancers are carcinomas, a type of cancer that begins in the linings of most organs.
The most common type of breast cancer is invasive ductal carcinoma, which accounts for approximately eight to 10 invasive breast cancer cases, according to the American Cancer Society. The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program estimates that 281,550 new cases of female breast cancer occurred in the United States in 2021, which means most of those cancers were invasive ductal carcinomas.
DCIS is the most common type of noninvasive breast cancer, with about 60,000 new cases diagnosed in the United States each year. About one in every five new breast cancer cases is ductal carcinoma in situ.
Also called intraductal carcinoma or stage 0 breast cancer, it’s considered a noninvasive breast cancer. With DCIS, abnormal and cancerous cells haven’t spread from the ducts into nearby breast tissue nor anywhere else, such as the lymph nodes.
DCIS is divided into several subtypes, mainly according to the appearance of the tumor. These subtypes include micropapillary, papillary, solid, cribriform and comedo.
Patients with ductal carcinoma in situ are typically at higher risk for seeing their cancer return after breast cancer treatment, although the chance of a recurrence is less than 30 percent. Most recurrences occur within five to 10 years after the initial breast cancer 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 ductal carcinoma in situ would require additional treatment.
The type of therapy selected may affect the likelihood of recurrence. Treating DCIS with a lumpectomy (breast-conserving surgery), and without radiation therapy, carries a 25 percent to 35 percent chance of recurrence. Adding breast cancer radiation therapy to the treatment decreases this risk to about 15 percent. Currently, the long-term survival rate for women with ductal carcinoma in situ is nearly 100 percent.
Sometimes, ductal carcinoma can become an invasive cancer. With invasive ductal carcinoma, cancer spreads from a milk duct, where it originates, into nearby tissue and lymph nodes. From there, it may spread, or metastasize, to other parts of the body, such as the bones and distant organs. Cancerous cells travel and spread through the lymph system (which is part of the immune system) or bloodstream.
About eight in 10 invasive breast cancers are invasive ductal carcinoma, according to the ACS.
Surgery typically is the first treatment for IDC. The goal of this treatment is to remove the cancer from the breast with a lumpectomy or mastectomy. The type of surgery recommended depends on factors such as the tumor’s size and location and whether more than one area in the breast has been affected. For patients with hormone-sensitive ductal carcinoma, long-term systemic treatment with tamoxifen is recommended to prevent recurrence.
LCIS is technically not considered cancer, but rather a change in the breast. In the breast are tens of thousands of tiny clusters of lobules to produce breast milk. Cells that resemble cancer cells may grow inside these lobules. LCIS tends to remain there and not spread. However, having LCIS puts you at an increased risk for invasive breast cancer, so your care team may want to monitor you in order to promptly address any changes.
Among the invasive breast cancers, about 10 percent are invasive lobular carcinomas, or ILC. This cancer starts in the breast’s milk-producing glands, which are called lobules, and may spread to other parts of the body. About 20 percent of women with ILC have cancer in both breasts, according to the ACS.
The treatment options for invasive lobular carcinoma include localized approaches such as surgery and radiation therapy that treat the tumor and the surrounding areas, as well as systemic treatments such as chemotherapy and hormonal or targeted therapies that travel throughout the body to destroy cancer cells that may have spread from the original tumor.
