Basics of Breast Cancer
Breast cancer is a cancer that starts in the tissues of the breast. There are two main types of breast cancer:
- Ductal carcinoma starts in the tubes (ducts) that move milk from the breast to the nipple. Most breast cancers are of this type.
- Lobular carcinoma starts in the parts of the breast, called lobules that produce milk.
In rare cases, breast cancer can start in other areas of the breast.
Breast cancer may be invasive or noninvasive. Invasive means it has spread from the milk duct or lobule to other tissues in the breast. Noninvasive means it has not yet invaded other breast tissue. Noninvasive breast cancer is called “in situ.”
- Ductal carcinoma in situ (DCIS), or intraductal carcinoma, is breast cancer in the lining of the milk ducts that has not yet invaded nearby tissues. It may progress to invasive cancer if untreated.
- Lobular carcinoma in situ (LCIS) is a marker for an increased risk of invasive cancer in the same or both breasts.
Many breast cancers are sensitive to the hormone estrogen. This means that estrogen causes the breast cancer tumor to grow. Such cancers have estrogen receptors on the surface of their cells. They are called estrogen receptor-positive cancer or ER-positive cancer.
Some women have what’s called HER2-positive breast cancer. HER2 refers to a gene that helps cells grow, divide, and repair themselves. When cells (including cancer cells) have too many copies of this gene, they grow faster. Experts think that women with HER2-positive breast cancer have a more aggressive disease and a higher risk that the disease will return (recur) than women who do not have this type.
Early breast cancer usually does not cause symptoms. This is why regular breast exams are important. As the cancer grows, symptoms may include:
- Breast lump or lump in the armpit that is hard, has uneven edges, and usually does not hurt
- Change in the size, shape, or feel of the breast or nipple — for example, you may have redness, dimpling, or puckering that looks like the skin of an orange
- Fluid coming from the nipple — may be bloody, clear to yellow, green, and look like pus
It is very rare yet men can get breast cancer too. Symptoms of breast cancer include breast lump and breast pain and tenderness.
Symptoms of advanced breast cancer may include:
- Bone pain
- Breast pain or discomfort
- Skin ulcers
- Swelling of one arm (next to the breast with cancer)
- Weight loss
Signs and tests
The doctor will ask you about your symptoms and risk factors. Then the doctor will perform a physical exam, which includes breasts, armpits, and the neck and chest area.
Tests used to diagnose and monitor patients with breast cancer may include:
- Breast MRI to help better identify the breast lump or evaluate an abnormal change on a mammogram
- Breast ultrasound to show whether the lump is solid or fluid-filled
- Breast biopsy, using methods such as needle aspiration, ultrasound-guided, stereotactic, or open
- CT scan to see if the cancer has spread
- Mammography to screen for breast cancer or help identify the breast lump
- PET scan
- Sentinel lymph node biopsy to see if the cancer has spread
If your doctor learns that you do have breast cancer, more tests will be done to see if the cancer has spread. This is called staging. Staging helps guide future treatment and follow-up and gives you some idea of what to expect in the future.
Breast cancer stages range from 0 to IV. The higher the staging number, the more advanced the cancer.
Cancer – breast; Carcinoma – ductal; Carcinoma – lobular; DCIS; LCIS; HER2-positive breast cancer; ER-positive breast cancer; Ductal carcinoma in situ; Lobular carcinoma in situ