The National Cancer Institute estimates that in 2010, doctors diagnosed breast cancer in 207,090 women and 1,970 men in the United States. This type of cancer starts in the tissue of the breast, and the exact location varies. As the cancer progresses, it can spread to the nearby tissue. Patients with breast cancer may feel a breast lump or have discharge coming from the nipple.
Ducts
In the breast, the ducts transport milk from the breast to the nipple. Two types of breast cancer start in this site of the breast: invasive ductal carcinoma and ductal carcinoma in situ. MedlinePlus explains that ductal carcinoma is the most common form of breast cancer. With invasive ductal carcinoma, the cancer spreads to surrounding tissue. With ductal carcinoma in situ, also known as inductal carcinoma, the cancer does not spread beyond the lining of the duct.
Lobules
Lobules are the part of the breast that produce the milk used during breastfeeding. The lobules connect to the ducts to the nipple. The type of breast cancer found in the lobule can be invasive lobular carcinoma or lobular carcinoma in situ. Like the ductal carcinoma in situ, the lobular carcinoma in situ does not spread beyond the lobule tissue. MedlinePlus notes that patients with lobular carcinoma in situ have an increased risk having of invasive breast cancer later, which may occur in the same breast or both breasts.
Stroma
The MayoClinic.com points out that in stage III breast cancer, the cancer can spread to the stroma. A fatty tissue, the stroma surrounds the ducts and lobules in the breast, as well as the lymph nodes and blood vessels. The stroma acts as a connective tissue.
Lymph Nodes
When the breast cancer becomes more advanced, it can spread to the lymph nodes, which are part of the immune system. The lymphatic vessels, which connect the lymph nodes, carry a clear fluid called lymph away from the breast. The American Cancer Society explains that the axillary nodes, the lymph nodes located under the arm, are the most connected lymph nodes to the breast. Other lymph nodes near the breast include the internal mammary nodes, located inside the chest; supraclavicular lymph nodes, located above the collarbone; and the infraclavicular lymph nodes, located below the collarbone. MayoClinic.com notes that in stage II breast cancer, the cancer spreads to the axillary nodes; by stage III, the cancer spreads to the supraclavicular lymph nodes.
References
- MedlinePlus Medical Encyclopedia: Breast Cancer
- National Cancer Institute: Breast Cancer Home Page
- American Cancer Society: What Is Breast Cancer?
- MayoClinic.com: Slide Show -- Stages of Breast Cancer -- Stage II Breast Cancer
- MayoClinic.com: Slide Show -- Stages of Breast Cancer -- Stage III Breast Cancer
