When a woman receives a diagnosis of breast cancer, one of the first questions she wants to know regards prognosis and survival. Breast cancer mortality has dropped over two percent a year since 1990, and rates continue to drop as doctors investigate novel ways of treating the number one cancer affecting American women.
Stage
Stage refers to the extent, or spread of the breast cancer. Doctors categorize breast cancer patients from stage 0 to stage IV, with stage 0 being the very earliest cancer and stage IV indicating that the cancer has spread, or metastasized to other parts of the body. Doctors conduct several tests when a woman receives a diagnosis of breast cancer to determine the stage of breast cancer, including imaging tests and possibly the removal of lymph nodes.
According to the American Cancer Society, the overall five-year survival rate for localized breast cancer is 98%. The survival rate for breast cancer that has spread to the chest wall or lymph nodes is in the 80% range, and at least a quarter of breast cancer patients with metastatic disease survive five years or more. These figures will continue to improve as clinical trials investigate better ways of treating breast cancer patients.
Age
Although it seems counterintuitive, the survival rate for breast cancer patients under the age of 40 is slightly lower than the survival rate for older breast cancer patients. This may be because younger patients develop cancers that grow more aggressively. Women over 40 experience a 7% gain in survival compared to women under 40.
Hormone Receptors
Doctors must evaluate the tissue of the breast cancer tumor to see if the naturally occurring hormones estrogen and progesterone help the cancer grow. If a woman’s breast cancer tissue is hormone positive, she may receive hormone therapy to block the effects of estrogen and progesterone on the cancer, even if it has spread to other parts of the body.
Grade
Pathologists can examine breast cancer cells under a microscope to determine the grade of the breast cancer tissue. When cancer cells closely resemble normal breast tissue of origin the cancer is described as well differentiated, or low grade. Low grade tumors grow and spread slowly. Breast cancer cells that look very abnormal or different from normal breast tissue are described as poorly differentiated, or high grade. These cancers grow quickly and may require therapy that is more aggressive.
Oncogene Expression
An oncogene is a piece of genetic material carried in the chromosome that can cause normal cells to develop into cancerous ones. An oncogene of particular interest to breast cancer researchers is the HER-2 breast cancer oncogene, produced by approximately one-third of breast cancer patients. Researchers note that breast cancer patients who express the HER-2 oncogene tend to have earlier cancer recurrences and lower survival rates. However, breast cancer patients with HER-2 over expression may be candidates for the drug Herceptin.
Cell Type
The most common type of breast cancer is epithelial, which refers to the common kind of tissue that lines all hollow organs and all passages of the digestive, respiratory, genital, and urinary systems. Researchers have associated some less common breast cancer subtypes with a favorable prognosis, including mucinous, medullary, and tubular carcinomas. Some rare types of cancer can also affect the breast, including sarcomas, but they aren’t classified as breast cancer.
Because a cancer patient’s prognosis depends on so many factors, the doctor is the best person to discuss an individual patient’s survival outlook. Use this discussion to ask informed questions of the doctor about what to expect.
Related Article: Cancer Survival Rates
Sources:
National Cancer Institute's PDQ Summary
American Cancer Society's Breast Cancer Facts and Figures 2007-2008
