Breast cancer occurs when cells within the breast undergo changes that cause it to grow and divide uncontrollably. The tumor that develops from this will destroy tissue around it.
What is going on in the body?
A tumor in the breast does not stop the breast from changing with the menstrual cycle or pregnancy or producing breast milk. A tumor will, however, 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. 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 can 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 distant from the breast. 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.
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 2 or more alcoholic beverages a day
- experiencing menopause after age 55
- having a first child after age 30, or not having children
- having denser breasts than usual
- 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 high-dose oral contraceptives for birth control.
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 the night shift
Women who smoke are more likely than nonsmokers to develop breast cancer that is estrogen-receptor negative. These women don't benefit from anti-hormone therapy. They generally have a poorer outcome from the cancer.
Women who breastfeed their children may lower their risk for breast cancer.
A woman may have every risk factor and never develop breast cancer or a woman may have no risk factors and still develop breast cancer.
At this time it is not possible to predict with absolute accuracy who will and who will not develop breast cancer.
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 and raloxifene, 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.
How is the disease diagnosed?
It is very important to detect breast cancer early, when it is much easier to cure. 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 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.
Breast self-examination (BSE) is an option for women to consider but the American Cancer Society no longer recommends monthly BSE for all women. A large recent study found no decrease in breast cancer deaths in women who performed monthly BSE. If a woman does detect a lump or change in her breasts when performing BSE, she should contact her health care provider.
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 your physician. Mammography is often not as 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.
If abnormalities are found on a screening mammogram, a diagnostic mammogram is usually 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 cellsthe presence of certain proteins, such as the HER2 gene that is associated with a higher risk of repeated breast cancersensitivity to estrogen or progesterone
- in some cases, a test for multiple genes that helps the physician predict the risk of relapse may also be performed
Long Term Effects
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 can 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.
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.
In general, treatment guidelines in the past have included 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. If it is responsive to hormones, medications like tamoxifen, anastrozole or letrozole can be used to suppress hormone activity. In the case of pre-cancerous tumors, tamoxifen may be used to help prevent a second breast cancer from developing.
- Early stage, no involved nodes. If the cancer is not responsive to hormones, the woman may be offered chemotherapy possibly followed by biological therapy. If it is responsive to hormones, medications like tamoxifen, anastrozole 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. A new test evaluating the presence of a series of genes has been developed that may determine whether patients who have early stage disease and who are responsive to hormones may need chemotherapy or not.
- Early stage, positive nodes. Chemotherapy will be offered to kill any remaining undetectable cancer possibly followed by biological therapy. Women whose cancer is responsive to hormones may 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. Usually, chemotherapy regimens last 3 to 6 months. 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 may be offered. Anti-hormone or biological treatments 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 relatively 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, a monoclonal antibody, is an example of one of these products. It slows or stops the growth of breast cancer cells that have 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 may cause hair loss, damage to the blood forming organ (bone marrow) which may result in bleeding, infection, anemia with the possible need for transfusions, damage to organs such as the liver, kidneys, heart, nervous system and skin, allergic reaction including shock, nausea and/or vomiting, and sores on the lips and loss of lining in the intestinal tract.
Radiation therapy therapy may cause some local burning and darkening of the skin, as well as some fatigue.
Anti-hormone therapy may cause menopausal symptoms, even in women who have already been through menopause.
Biological response modifiers can cause heart failure, rash, swelling, or flu-like symptoms.
For people with early stage disease, the side effects of therapy should 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 or radiation therapy, the breast can be reconstructed - and many centers perform reconstructive surgery at the time of lumpectomy. Others may advise to defer reconstruction until therapy is finished and a period of time has lapsed.
Reconstruction aims to 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 may help to restore complete function.
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 of the visits may 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 bloodwork, bone scans or CAT scans, may be used to follow the disease. Any new or worsening symptoms should be reported to the healthcare provider.
Jardines,L.; Haffty,B.G.;&Theriault, R.L (1996). Breast Cancer in Cancer Management: A Multidisciplinary Approach. PRR: Huntington, NY. Pp. 21-52.