Breast cancer is the most common cancer in women, after skin cancer. It is a malignant (cancerous) tumor. Breast cancer begins when the cells that makeup the breast tissue divide uncontrolled and cause a tumor to form. When breast cancer spreads, it commonly spreads to the lymph nodes near the breast, and when it spreads beyond the lymph nodes, it usually spreads to the bones, lungs and liver.
The breast is made of glands that make milk called lobules, small tubes that carry the milk to the nipple called ducts, and fatty tissue, blood vessels and lymph. 75% of all breast cancer cases begin in the cells of the milk ducts. It often starts as a precancerous condition called DCIS (ductal carcinoma in situ) which is usually detected on your mammogram. It can progress into a cancer called ductal carcinoma. The second most common kind of breast cancer is Lobular carcinoma and it develop from your lobules (milk sacs).
A rare, but important cancer of the breast is called inflammatory breast cancer, where there is no lump and the breast appears red and swollen, and warm. It is more malicious than the other main types of breast cancer and is often mistaken for an infection.
Most breast lumps are benign, not cancerous, and do not spread.
High Risk Breast Lesions
There are several lesions found in the breasts which are not a type of cancer but are an indicator that you are at a higher than normal risk of developing a breast cancer. These are often found by the radiologist on mammogram and can include things like:
- Lobular carcinoma in situ (LCIS)
Types of Malignant Breast Conditions
- Ductal carcinoma In Situ – A precancerous condition located within the milk ducts. Under certain conditions DCIS can evolve to become breast cancer. It is often discovered on a mammogram.
- Invasive Ductal Carcinoma – Invasive ductal carcinoma (IDC) is the most common breast cancer. It starts in the duct and invades the breast tissues and can affect nearby lymph nodes.
- Invasive Lobular Carcinoma – Invasive Lobular carcinoma (ILC) starts in the milk glands, and spreads to the breast tissue and nearby lymph nodes, and other parts of the body.
Breast Cancer Subtypes
- Hormone receptor positive- the cancer is expressing estrogen receptors (ER) and progesterone (PR) receptors, meaning these cancers depend on these hormones in order to grow. Hormone receptor positive cancer is most frequent in postmenopausal women. 60-75% of all breast cancers have estrogen and progesterone receptors.
- HER2 positive- these cancers depend on a gene to grow. The gene is named the human epidermal growth factor receptor 2. These cancers tend to grow more quickly, but there are several effective drugs for this subtype.
- Triple negative- when a tumor doesn’t express ER, PR and/or HER2, it is called Triple Negative- and makes up about 15% of cases of invasive breast cancer. This subtype grows more quickly that HER2 positive, and hormone receptor positive ER and PR. But it is very sensitive to chemotherapy. Triple- negative is more common in young women, and especially in young black women. Triple negative is the most common type of breast cancer diagnosed in women with the BRCA1 mutation.
- BRCA 1 &2 are inherited gene mutations that increase the risk of breast and ovarian cancer. Together these mutations account for about 25% of hereditary cancers, and 10% of all breast cancers. A positive test means the patient has an increased risk of breast cancer. This section should be moved, it is not a type of breast cancer, also the percentages should be checked
- Being a woman
- Risk increases with age
- Genetic risk-BRCA1, BRCA2, and other gene mutations associated with breast cancer
- Family history- if the patient has a family history, genetic testing for BRCA genes is recommended.
- White, African American
- Dense breast tissue
- Benign breast changes
- Women who began menstruation before age 12 or post-menopausal women over 55
- Radiation treatments at some point in their lives
- Women who have no children or have them after age 30
- Alcohol is directly linked to an increased risk of breast cancer
- Obesity is also linked to higher risk
Symptoms include a lump or mass that is painless and hard, swelling of the breast, skin irritation or dimpling, breast pain, nipple pain, nipple turning inward, redness, thickening of the skin and nipple discharge.