Overview, Causes, & Risk Factors
Breast cancer occurs when a cell within a breast undergoes changes that cause it to grow and divide uncontrollably. The tumor that develops from this will destroy tissue around it. Any tissue in the breast can be affected. Usually the cancer arises from tissue that forms milk ducts. Both women and men can develop breast cancer, but it is very rare in men.
What is going on in the body?
A tumor in the breast does not affect the bodily function of the breast. For example, the breast may remain sensually active. It can change with the menstrual cycle or pregnancy and can produce breast milk. A tumor will cause destruction of tissue within the breast. Spread of the tumor to other parts of the body can cause death.
Cancer of the breast can be detected when it grows large enough to either be felt or seen on a mammogram. Sometimes a tumor isn't found for many years. The tumor may distort the shape of the breast or the texture of the skin as it becomes larger. This is because surrounding tissues become fixed to the tumor. The tumor will grow through the breast to the outer skin if left untreated.
Cancer cells can also enter specialized channels in the breast called lymphatics. Cancer cells travel through the lymphatics to the lymph nodes to form tumors. This most commonly occurs in lymph nodes under the armpit or within the chest. This may occur when the tumor has grown large, but it can also happen sooner.
Cancer cells can also spread, or metastasize, to other parts of the body through the bloodstream. This can occur when the tumor is large or small. These cells can travel to other tissues and form new tumors. Breast cancer is most often spread to the bones, lungs, brain, and liver. However, any tissue can be affected.
What are the causes and risks of the disease?
The risk for any woman to develop breast cancer is significant, about 1 in 9 over a lifetime. Breast cancer is also seen in men but is much less common. About 5% to 10% of all breast cancers may be related to genes that are passed through families, called BRCA1 and BRCA2. Research has shown that women are also at greater risk of developing breast cancer if the following conditions apply.
They have a personal history of breast cancer in the other breast.
They have close blood relatives, like a mother or sister, who developed breast cancer before menopause.
They have a history of certain changes in the breast tissue, including a condition known as atypical hyperplasia.
There is evidence that the following conditions also contribute to a higher risk for breast cancer:
beginning menstruation before age 12
drinking alcohol
experiencing menopause after age 55
having a first child after age 30, or not having children
having denser breasts
receiving radiation therapy to the breast before age 30, especially for Hodgkin's lymphoma
using diethylstilbesterol, or DES, during pregnancy
using estrogen, such as hormone replacement therapy for menopause
using oral contraceptives for birth control, if there is a strong family history of breast cancer
Other risk factors have been tentatively identified, but need more study. They include the following:
being obese
eating a diet high in fat
using hormones such as progesterone
working a night shift
Women who smoke are more likely to develop breast cancer that is estrogen-receptor negative. These women don't benefit from antihormone therapy. They generally have a poorer outcome from the cancer.
Women who breastfeed their children may lower their risk for breast cancer. However, a woman may have every risk factor and never develop breast cancer. A woman may have no risk factors and develop breast cancer. At this time it is not possible to predict with absolute accuracy who will and who will not develop breast cancer.
Symptoms & Signs
What are the signs and symptoms of the disease?
Early in the disease, the only symptom may be a painless lump in the breast. This lump must be about the size of the fingertip before it can be felt. It can be anywhere in the breast. The lump is usually very hard and may not move when touched.
At a later stage in the disease, the person may have the following symptoms of breast cancer:
breast or nipple skin that is warm, red, swollen, or scaly
change in the shape or size of the breast
a lump or thickening near the breast, or in the underarm
nipple discharge that is not breast milk
nipple tenderness
a nipple that is turned inward, or inverted
a rash around the nipple that may bleed, itch, or cause skin breakdown
ridges or pits in the breast
skin that is dimpled like an orange
When the disease has advanced further, the person may have swelling in the lymph nodes in the armpit. He or she can also have symptoms related to the spread of the cancer. For instance, breast cancer that has spread to the bone will cause pain in the affected area.
Diagnosis & Tests
How is the disease diagnosed?
Lumps may be found by a woman or her partner. Some lumps are detected by the healthcare provider during a physical exam. Sometimes the lump cannot be felt but is found on a screening mammogram. If abnormalities are found on a screening mammogram, a diagnostic mammogram may be done. An ultrasound may be done to show whether the lump is a fluid-filled cyst or a solid mass.
After the lump is discovered, a tissue sample must be taken to determine if it is cancer. Tissue samples may be obtained with the following procedures:
Ductal lavage. A very thin needle is inserted into a milk duct and cells are washed out with saline.
Excisional biopsy. The surgeon removes all of the lump or suspicious tissue, as well as a surrounding area of healthy tissue.
Fine needle aspiration. The provider uses a thin needle to obtain fluid and cells from the lump.
Incisional biopsy. A surgeon removes a sample of the lump or suspicious tissue.
Needle biopsy. If the lump is seen only on mammogram, a needle is guided under X-ray to take a sample.
The fluid and tissue will be carefully studied to determine first if it is cancer. If so, the tissue then will be tested to see how aggressive the cancer is. A woman may also undergo other specialized X-rays to see if the cancer has spread beyond the breast.
Other tests will be done to determine factors that will affect treatment choices. The most common factors are as follows:
aggressiveness of the tumor cells
the presence of certain proteins, such as the HER2 gene that is associated with a higher risk of repeated breast cancer
sensitivity to estrogen or progesterone
Prevention & Expectations
What can be done to prevent the disease?
Rigorous scientific studies have found no diet or other similar intervention to prevent breast cancer. Studies are underway to see if certain medications can prevent the development of breast cancer in high risk women. The medicines, including tamoxifen, are not expected to be 100% effective, and they may have serious side effects. There is no other proven method to effectively prevent this cancer.
It is very important to detect breast cancer early, when it is much easier to cure. Every woman should do a monthly breast self-exam to detect any unusual lumps. A healthcare provider should check the woman's breasts during routine physical exams every 2 years for women younger than 40. After the age of 40, women should have the exam on a yearly basis.
According to the American Cancer Society, all women over 40 years of age with or without symptoms should have a mammogram once a year. Other organizations have different recommendations. However, all of these organizations agree that every woman over the age of 50 years should have an annual mammogram.
For women with an increased risk for breast cancer, there are no established guidelines for the age to start using screening mammography. This should be discussed and decided with the physician. Mammography is often not useful in women under the age of 35 with current techniques because the breast tissue is too dense to allow accurate interpretation of the X-rays.
What are the long-term effects of the disease?
Breast cancer is fatal if left untreated. It can be cured in the early stages. Once cured, the person will live a normal life. Loss of the breast may be emotionally upsetting. Reconstruction of the lost breast may assist with emotional adjustment.
What are the risks to others?
Breast cancer is not contagious and poses no direct risks to others. When a woman has breast cancer, this may indicate that other close female relatives are at risk. This does not mean that she will spread it.
Treatment & Monitoring
What are the treatments for the disease?
Treatment depends on factors found when the tumor was diagnosed and how advanced the cancer is at that time. Early stage cancers can be cured. Advanced stage cancers can often be controlled for long periods. Except for very small ductal carcinomas in situ, or DCIS, most cancers will be treated with additional surgery after diagnosis.
Treatment of breast cancer depends on the type of cancer and how far it has spread. Treatment guidelines include the following:
Very early stage, low grade tumors. These cancers are very small and in one location. In this case, removing just the affected part of the breast with a lumpectomy may be all that is required. Radiation therapy to the affected area may also be recommended.
Early stage, no involved nodes. If the cancer is not responsive to hormones, the woman may be offered chemotherapy. If it is responsive to hormones, medications like tamoxifen or letrozole can be used to suppress hormone activity. Both treatments are to ensure that any possible cancer left behind is killed or suppressed. Radiation therapy to the affected area may also be recommended.
Early stage, positive nodes. Chemotherapy will be offered to kill any remaining undetectable cancer. Women whose cancer is responsive to hormones will also receive tamoxifen or similar antihormone medications. The kind of chemotherapy and intensity of the regimen will be determined by other factors in the tumor. Radiation therapy to the affected area may also be recommended.
Advanced stage. When the cancer has spread to nearby structures or to other areas of the body, the goal will be to control the cancer. Chemotherapy will be offered. Antihormone medications can be given to women whose tumors are likely to respond. Other medicine to treat problems caused by the advancing cancer will be used to relieve symptoms. Radiation therapy to the affected area may also be recommended.
Biological response modifiers are a fairly new treatment used for certain types of breast tumors. These products target breast cancer cells that have too much of a protein known as HER2. Trastuzumab is an example of one of these products. It slows or stops the growth of breast cancer cells with too much HER2. It can be used alone or with chemotherapy.
What are the side effects of the treatments?
Surgery may cause bleeding, infection, and allergic reaction to anesthesia. Chemotherapy and radiation therapy may cause hair loss, fatigue, and nausea. These treatments also increase an individual's risk of infection temporarily. Antihormone therapy may cause menopausal symptoms, even in women who have already been through menopause. Biological response modifiers can cause rash, swelling, or flu-like symptoms.
For people with early stage disease, the side effects of therapy will eventually subside. Those with advanced disease may require changes in therapy to keep the cancer in control.
What happens after treatment for the disease?
After surgery, the breast can be reconstructed. Reconstruction will restore the normal shape to the breast following lumpectomy or mastectomy. The nerves to the breast area may be cut and the area may remain numb. At first, movement may be restricted. Physical therapy and exercise will restore complete function.
The emotional health of the individual is an important component in breast cancer survival. New research has shown that women who repress, or control, their emotions have an imbalance in stress hormone levels. These imbalances can predict early death in women whose breast cancer has spread to other parts of the body. Another study showed a longer survival rate in women who had good emotional support and were able to express their emotions.
A recent study of 400 breast cancer survivors showed that the women listed the following factors as key to breast cancer survival:
complementary therapies, or alternative medicine
exercise
healthy diet
healthy lifestyle
positive attitude
prayer
stress reduction
tamoxifen
How is the disease monitored?
After completing therapy, a person with early stage disease will have regular visits with the healthcare provider. The provider will monitor the cancer with physical exams, mammograms, and other tests. The provider will look for signs that the cancer has returned. Over time, the frequency will decrease.
For those whose cancer is advanced, more frequent monitoring of the progress of the disease and the effect of treatment is necessary. Tests, such as bone scans or CAT scans, will be used to follow the disease. Any new or worsening symptoms should be reported to the healthcare provider.
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