According to the American Cancer Society, 1 in 8 women in the United States will develop invasive breast cancer during their lifetime. While this number may seem high, most women who develop breast cancer and receive early treatment do not experience a recurrence of the disease.
Types of Breast Cancer
There are many types of breast cancer, though some of them are quite rare. Treatment plans will differ according to the type and stage of cancer. The following types account for the most common types of breast cancer:
- Ductal carcinoma in situ (DCIS): This type is considered noninvasive or pre-invasive breast cancer. The cells that lined the ducts have changed to look like cancer cells, but have not spread through the walls of the duct to the surrounding tissue. DCIS accounts for about 20 percent of new breast cancer cases, and nearly all women diagnosed at this early stage of breast cancer can be cured.
- Invasive (or infiltrating) ductal carcinoma (IDC): The most common type of breast cancer, IDC begins in a milk duct of the breast, breaks through the wall of the duct, and then grows into the fatty breast tissue.
- Invasive (or infiltrating) lobular carcinoma (ILC): ILC starts in the milk-producing glands and, similarly to IDC, it can spread to other parts of the body. ILC accounts for about 10 percent of invasive breast cancer cases.
A cancer’s stage is one of the most important determining factors for prognosis and treatment options. The stage of breast cancer signifies how widespread the cancer is when it is first diagnosed.
The most common staging system for breast cancer is the American Joint Committee on Cancer (AJCC) TNM system. From the American Cancer Society:
The TNM staging system classifies cancers based on their T, N, and M stages:
- The letter T followed by a number from 0 to 4 describes the tumor's size and spread to the skin or to the chest wall under the breast. Higher T numbers mean a larger tumor and/or wider spread to tissues near the breast.
- The letter N followed by a number from 0 to 3 indicates whether the cancer has spread to lymph nodes near the breast and, if so, how many lymph nodes are affected.
- The letter M followed by a 0 or 1 indicates whether the cancer has spread to distant organs -- for example, the lungs or bones.
Breast Cancer in Men
Males possess a very small amount of non-functioning breast tissue. While uncommon, males can get breast cancer as well. Breast cancer in men accounts for about 1 percent of all cases. Because men have so little breast tissue, lumps are easily felt and are therefore easily accessible for biopsies and diagnosis. Treatment for breast cancer in males – as in women – depends on the extent and severity of the disease.