Inside a woman's breast are 15 to 20 sections called lobes. Each lobe is made of many smaller sections called lobules. Lobules have groups of tiny glands that can make milk. After a baby is born, a woman's breast milk flows from the lobules through thin tubes called ducts to the nipple. Fat and fibrous tissue fill the spaces between the lobules and ducts.
The breasts also contain lymph vessels. These vessels are connected to small, round masses of tissue called lymph nodes. Groups of lymph nodes are near the breast in the underarm (axilla), above the collarbone, and in the chest behind the breastbone
Cancer begins in cells, the building blocks that make up tissues. Tissues make up the breasts and other parts of the body.
Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.
Sometimes, this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a lump, growth, or tumor.
Tumors in the breast can be benign (not cancer) or malignant (cancer). Benign tumors are not as harmful as malignant tumors:
- are rarely a threat to life
- can be removed and usually don't grow back
- don't invade the tissues around them
- don't spread to other parts of the body
- may be a threat to life
- often can be removed but sometimes grow back
- can invade and damage nearby organs and tissues (such as the chest wall)
- can spread to other parts of the body
The spread of cancer is called metastasis.
Risk factors you cannot change include:
- Age and gender -- Your risk of developing breast cancer increases as you get older. Most advanced breast cancer cases are found in women over age 50. Women are 100 times more likely to get breast cancer than men.
- Family history of breast cancer -- You may also have a higher risk for breast cancer if you have a close relative who has had breast, uterine, ovarian, or colon cancer. About 20 - 30% of women with breast cancer have a family history of the disease.
- Genes -- Some people have genes that make them more likely to develop breast cancer. The most common gene defects are found in the BRCA1 and BRCA2 genes. These genes normally produce proteins that protect you from cancer. If a parent passes you a defective gene, you have an increased risk for breast cancer. Women with one of these defects have up to an 80% chance of getting breast cancer sometime during their life.
- Menstrual cycle -- Women who got their periods early (before age 12) or went through menopause late (after age 55) have an increased risk for breast cancer.
- Alcohol use -- Drinking more than 1 - 2 glasses of alcohol a day may increase your risk for breast cancer.
- Childbirth -- Women who have never had children or who had them only after age 30 have an increased risk for breast cancer. Being pregnant more than once or becoming pregnant at an early age reduces your risk of breast cancer.
- DES -- Women who took diethylstilbestrol (DES) to prevent miscarriage may have an increased risk of breast cancer after age 40. This drug was given to the women in the 1940s - 1960s.
- Hormone replacement therapy (HRT) -- You have a higher risk for breast cancer if you have received hormone replacement therapy with estrogen for several years or more.Obesity -- Obesity has been linked to breast cancer, although this link is controversial. The theory is that obese women produce more estrogen, which can fuel the development of breast cancer.
- Radiation -- If you received radiation therapy as a child or young adult to treat cancer of the chest area, you have a much higher risk for developing breast cancer. The younger you started such radiation and the higher the dose, the higher your risk -- especially if the radiation was given during breast development.
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
Men can get breast cancer, too. Symptoms 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)
The doctor will ask you about your symptoms and risk factors. Then the doctor will perform a physical exam, which includes both breasts, armpits, and the neck and chest area.
Signs and tests
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
- Sentinal lymph node biopsy to see if the cancer has spread
Breast cancer stages range from 0 to IV. The higher the staging number, the more advanced the cancer.
- Type and stage of the cancer
- Whether the cancer is sensitive to certain hormones
- Whether the cancer overproduces (overexpresses) a gene called HER2/neu
- Chemotherapy medicines to kill cancer cells
- Radiation therapy to destroy cancerous tissue
- Surgery to remove cancerous tissue -- a lumpectomy removes the breast lump; mastectomy removes all or part of the breast and possible nearby structures
- An example of hormonal therapy is the drug tamoxifen. This drug blocks the effects of estrogen, which can help breast cancer cells survive and grow. Most women with estrogen-sensitive breast cancer benefit from this drug.
- Another class of hormonal therapy medicines called aromatase inhibitors, such as exemestane (Aromasin), have been shown to work just as well or even better than tamoxifen in postmenopausal women with breast cancer. Aromatase inhibitors block estrogen from being made.
Cancer treatment may be local or systemic.
- Local treatments involve only the area of disease. Radiation and surgery are forms of local treatment.
- Systemic treatments affect the entire body. Chemotherapy is a type of systemic treatment.
- Stage 0 and DCIS -- Lumpectomy plus radiation or mastectomy is the standard treatment. There is some controversy on how best to treat DCIS.
- Stage I and II -- Lumpectomy plus radiation or mastectomy with some sort of lymph node removal is the standard treatment. Hormone therapy, chemotherapy, and biologic therapy may also be recommended following surgery.
- Stage III -- Treatment involves surgery, possibly followed by chemotherapy, hormone therapy, and biologic therapy.
- Stage IV -- Treatment may involve surgery, radiation, chemotherapy, hormonal therapy, or a combination of these treatments.
Women who have had a mastectomy may have reconstructive breast surgery, either at the same time as the mastectomy or later.
How well you do after being treated for breast cancer depends on many things. The more advanced your cancer, the poorer the outcome. Other factors used to determine the risk for recurrence and the likelihood of successful treatment include:
- Location of the tumor and how far it has spread
- Whether the tumor is hormone receptor-positive or -negative
- Tumor markers, such as HER2
- Gene expression
- Tumor size and shape
- Rate of cell division or how quickly the tumor is growing
You may experience side effects or complications from cancer treatment. For example, radiation therapy may cause temporary swelling of the breast (lymphedema), and aches and pains around the area.
Lymphedema may start 6 to 8 weeks after surgery or after radiation treatment for cancer.
It can also start very slowly after your cancer treatment is over. You may not notice symptoms until 18 to 24 months after treatment. Sometimes it can take years to develop.
Ask your doctor about the side effects you may have during treatment.
Tamoxifen is approved for breast cancer prevention in women aged 35 and older who are at high risk. Discuss this with your doctor.
Women at very high risk for breast cancer may consider preventive (prophylactic) mastectomy. This is the surgical removal of the breasts before breast cancer is ever diagnosed. Possible candidates include:
- Women who have already had one breast removed due to cancer
- Women with a strong family history of breast cancer
- Women with genes or genetic mutations that raise their risk of breast cancer (such as BRCA1 or BRCA2)
Your doctor may do a total mastectomy to reduce your risk of breast cancer. This may reduce, but does not eliminate the risk of breast cancer.
Many risk factors, such as your genes and family history, cannot be controlled. However, eating a healthy diet and making a few lifestyle changes may reduce your overall chance of getting cancer.
There is still little agreement about whether lifestyle changes can prevent breast cancer. The best advice is to eat a well-balanced diet and avoid focusing on one "cancer-fighting" food. The dietary guidelines for cancer prevention we recommend that people:
Regular Self Examination a must for prevention
- Choose foods and portion sizes that promote a healthy weight
- Choose whole grains instead of refined grain products
- Eat 5 or more servings of fruits and vegetables each day
- Limit processed and red meat in the diet
- Limit alcohol consumption to one drink per day (women who are at high risk for breast cancer should consider not drinking alcohol at all).
Contact your doctor for an appointment if:
- You have a breast or armpit lump
- You have nipple discharge
- Nipple discharge
- Rash on the breast
- New lumps in the breast
- Swelling in the area
- Pain, especially chest pain, abdominal pain, or bone pain