Breast Cancer
Contents:
Breast cancer is a malignant (cancerous) tumour that starts in the cells of the breast. The disease occurs mostly in women, but men can also get breast cancer. This information concentrates on female breast cancer.
Virtually all breast cancers begin in the glandular tissue of the breast. 85% of breast cancers begin in the lining of the milk ducts and are called ductal carcinoma. 15% of breast cancers begin in the lobules, the glands that can produce and release milk, and are called lobular carcinoma.
When breast cancer spreads outside the ducts or lobules it is known as ‘invasive’. Most breast cancers are invasive.
Breast cancer can often spread from the site of the initial cancer to the lymph nodes under the arm, and from there to other parts of the body. This is known as Metastatic breast cancer.
Age
Increasing age is the biggest single risk factor for breast cancer.
Age at first child
The younger a woman is when she begins child bearing the lower her risk of breast cancer.
Age at menopause
A late menopause can increase the risk of breast cancer.
Age of first menstruation
Women who begin menstruating at an early age seem to have an increased risk of breast cancer.
Alcohol
Recent studies have suggested a link between alcohol and an increased risk of breast.
Antiperspirants and deodorants
There are no studies that prove any connection between anti-perspirants, deodorants and breast cancer. Even if the antiperspirant were concentrated in the armpit lymph nodes, the lymphatic fluid would not drain away to the breast.
Birth control pills
Modern day birth control pills contain a low dose of the hormones estrogen and progesterone. Some studies have associated them with a small increased risk of breast cancer. Today's birth control pills can provide some protection against ovarian cancer.
Breast feeding
Some studies have shown that the longer a woman breast feeds the greater the protection from breast cancer.
Childbearing
Having children reduces the risk of breast cancer.
Eating high-fat foods
Several large studies have failed to demonstrate a clear connection between eating high-fat foods and a higher risk of breast cancer. Ongoing studies are attempting to clarify this issue further. Avoidance of high-fat foods is a healthy choice for other reasons, for example to help lower cholesterol and maintain a healthy weight.
Excess body weight can increase the risk of breast cancer, because the extra fat increases the production of estrogen outside the ovaries and adds to the overall level of estrogen in the body.
Family history of breast cancer
Every woman has some risk of breast cancer. About 80% of women who get breast cancer have no known family history of the disease. Breast cancer risk is higher among women whose close blood relatives have the disease, either on the mother or father’s side. Having a mother, sister, or daughter with breast cancer approximately doubles a woman’s risk.
Genetics
To date, most inherited cases of breast cancer have been associated with one or other of two genes: BRCA1, which stands for BReast CAncer gene one, and BRCA2, or BReast CAncer gene two.
These genes should keep breast cells growing normally and prevent any cancer cell growth. When these genes contain abnormalities, or mutations, they are associated with an increased risk of breast cancer. Abnormal BRCA1 and BRCA2 genes may account for up to 10% of all breast cancers.
Women diagnosed with breast cancer that have an abnormal BRCA1 or BRCA2 gene often have a family history of breast cancer, ovarian cancer, or both. Identifying BRCA1 and BRCA2 has led to new techniques for detecting and treating breast cancer. If women wish to be tested they can now find out if they have two normal genes.
There is still a lot more to learn about these genes. It is probable that other genes also play a role in the development of breast cancer for women both with and without a family history of the disease.
HRT (hormone replacement therapy)
Hormone replacement therapy (HRT) is taken by many women during or following the menopause. It is thought that long-term use (several years or more) of combined HRT (estrogens together with progesterone) may slightly increase the risk of breast cancer as well as the risk of heart disease, blood clots, and strokes. HRT also seems to reduce the effectiveness of mammograms. Five years after stopping HRT, the breast cancer risk appears to drop back to normal.
Ionising Radiation
Excessive exposure to ionizing radiation should be avoided as it has been linked to an increased risk of breast cancer.
Reproductive history
Women in developed countries have an increased risk of developing breast cancer than those in less developed countries. This can possibly be explained by women having fewer children and spending less time breast feeding.
Life Style
Cutting down on alcohol consumption and maintaining a healthy body weight may help to prevent breast cancer.
Exercise
Recent studies have suggested that physical activity may have a preventative effect on breast cancer.
Preventative Mastectomy (also known as Prophylactic mastectomies)
Some women who have the abnormal BRCA1 and BRCA2 genes and are at a high risk from developing breast cancer have the option of a preventative mastectomy. This means that they have both breasts removed before any signs of cancer are found.
Removing the breast before there's any sign of disease lowers the risk of getting breast cancer by about 90%.
Prophylactic ovary removal
Women who have the abnormal BRCA1 and BRCA2 genes and have a higher risk of developing breast cancer have the option of preventative ovary removal. Recent research suggests removing the ovaries prophylactically lowers the risk of getting breast cancer by about 50% and the risk of ovarian cancer by about 50-80%. The removal of the ovaries lowers the amount of estrogen available to stimulate the start or development of breast cancer.
However the study was not randomized and the follow up period was relatively short, only two years on average.
Self examination
Women should get in to the habit of examining their breasts regularly. After the menopause women should also have their breasts examined by a health care professional. Any lump found should be reported to a doctor immediately.
Genetic Screening
Changes in certain genes make women more susceptible to breast cancer. If there is a history of breast cancer genetic testing can determine whether a woman has these abnormal genes.
Mammograms
A mammogram is an X-ray photograph of the breast and can help doctors diagnose and evaluate women who have breast cancer. Mammograms don't prevent breast cancer, but they can save lives by finding breast cancer as early as possible
Mammograms are recommended for women over 30 if there is a high risk of breast cancer, such as a strong family history of breast or ovarian cancer, or radiation treatment to the chest in the past. Leading American experts now recommend annual mammograms for all women over 40. However in Europe annual mammograms are suggested for women over the age of 50, as randomised trials of screening the 40-50 age group are still immature.
Mammograms aren't 100% accurate, normal breast tissue can sometimes hide a breast cancer so that it doesn't show up on a mammogram. Another issue is that a mammography can sometimes show up an abnormality that looks like a cancer, but turns out to be normal. However Mammograms are very safe and are at present the most accurate method of detecting breast cancer.
The widespread use of screening mammography has increased the number of breast cancers found before they cause any symptoms.
The most common sign of breast cancer is a new lump or mass. A lump that is painless, hard, and has uneven edges is more likely to be cancer. But sometimes cancers can be tender, soft, and rounded.
Other signs of breast cancer include the following:
- A swelling of part of the breast
- Skin irritation or dimpling
- Nipple pain or the nipple turning inward
- Redness or scaliness of the nipple or breast skin
- A nipple discharge (other than breast milk)
- A lump in the underarm area
Diagnostic tests (such as MRI magnetic resonance imaging, ultrasound, blood tests, or bone scans) are used when breast cancer is suspected or has been diagnosed.
PET scans (Positron Emission Tomography)
PET scans are still in the experimental phase for detecting breast cancer. A small amount of radioactive material is injected in to the body. Active cells, which often indicate rapid cancer growth, take up the radioactive material. The radiologist can identify areas where cells are suspiciously active which can indicate cancer.
PET scanning can sometimes show whether a tumour still exists after treatment and whether a cancer has spread to the lymph nodes. However PET scans are not very effective at detecting small tumours and require exceptional expertise to use.
MRI (Magnetic Resonance Imaging)
MRI uses magnetic fields to create images of the body. The best MRI technique involves the use of a special "breast coil." During an MRI, the body is moved in and out of a narrow tube as the machine creates images of the body.
The value of using MRI to detect breast cancer remains uncertain. Some doctors believe MRI can distinguish a breast cancer from normal breast gland tissue better than other techniques. However MRI is expensive and requires highly specialised equipment and highly trained experts.
If breast cancer has spread MRI can help evaluate other parts of the body. For example a woman who has progressive back pain can have an MRI scan of her back. The scan can help identify serious conditions such as the possible presence of a spinal tumour or brain metastasis.
Ultrasound
An ultrasound uses sound waves to outline a part of the body. The sound wave echoes are picked up by a computer to create an image that is displayed on a computer screen. Ultrasound has become a good method to use with mammograms. It is often used to look more closely at a certain area of concern found by the mammogram. It also helps to tell the difference between cysts and solid masses without using a needle to draw out fluid.
Treatment depends on the size and location of the breast cancer and how advanced the cancer has become. Treatment may involve surgery, chemotherapy, hormone therapy or radio therapy, or a combination of these treatments in varying orders.
Surgery
The following are the different types of surgery that may be used to treat breast cancer.
Lumpectomy
Breast-conserving surgery, (including lumpectomy) is when the cancerous tumour and a rim of normal tissue are removed from the breast. This is usually followed by radiation therapy to the remaining breast tissue. Recommendations for whole body or "systemic" treatments such as hormonal therapy, chemotherapy, or both, may follow.
Quadrantectomy
The malignant tumour and a larger rim of normal tissue are removed from the breast.
Total Mastectomy
Mastectomy is when the whole breast is removed during surgery. A double Mastectomy is when both breasts are removed. Sometimes radiation is given after mastectomy. Recommendations for whole body or "systemic" treatments such as hormonal therapy, chemotherapy, or both, may follow.
Modified Radical Mastectomy
The whole breast is removed, along with underarm lymph nodes.
Radical Mastectomy
The whole breast, chest muscles, all of the lymph nodes under the arm, and some additional fat and skin are removed.
Axillary lymph node Dissection
For invasive breast cancer axillary dissection often accompanies mastectomy or lumpectomy. Underarm lymph nodes are removed and tested to determine if cancer has spread.
Sentinel Lymph Node Dissection
This is a new technique and involves removing only one or a few underarm lymph nodes nearest to the breast tumour. These nodes are identified using a radioactive substance or blue dye injected near the tumour site within the breast. This can be a good alternative to traditional lymph node dissection for early-stage breast cancer.
Radiation Therapy/ Radiotherapy
Radiation or radiotherapy is a highly targeted, effective way to destroy cancer cells that may linger after surgery. This reduces the risk of the cancer recurring.
High-energy beams of radiation are focused on the breast from which cancer was removed. Over time, this focused radiation damages cells that are in the path of its beam—normal cells as well as cancer cells.
Cancer cells grow quickly by making new cells, which makes them very vulnerable to radiation damage. Because cancer cells are more dis-organised than healthy cells, they are less able to repair from radiation damage and recover. The cancer cells are more easily destroyed by radiation, while healthy, normal cells repair themselves and survive.
External radiation
Most radiation is usually given externally. A large machine called a linear accelerator delivers high-energy radiation to the affected breast. This is an outpatient treatment delivered in daily sessions Monday to Friday over five to seven weeks.
Radiation treatment is usually delivered to the breast from two different treatment fields which face each other. The two fields come from opposite directions. One starts from the side of the breast and faces the middle of the chest (where the breastbone is) and one starts in the middle of the chest and faces the side. The radiation oncologist can maximise the amount of radiation delivered to the breast area and minimize radiation received by other parts of the body.
Internal radiation
In some cases, internal radiation also called "brachytherapy" or "high-dose intracavitary radiation" will be recommended. With this technique, radioactive material is temporarily placed inside the breast, where the tumour used to be. This is typically reserved for the end of treatment and is given as an additional "boost," to supplement the regular radiation given to the whole breast.
In some cases internal radiation limited to the area where the cancer was found might be as effective as whole-breast radiation. The studies on this type of radiation treatment are still on going.
Electron Intraoperative therapy
Electron Intraoperative therapy (ELIOT) is a new treatment combining surgery and radiotherapy. Radio therapy is delivered directly to the open breast during surgery, enabling patients to have their breast cancer removed and their radio therapy treatment all in one visit to the hospital. The new treatment also limits radiation exposure to the rest of the patients’ skin and other organs, preventing further tissue damage.
After the cancer is removed a protective plate is inserted under the breast tissue and the radio therapy arm is placed directly above the open breast. Electrons are targeted directly on to the area where the tumour grew. The whole process is carefully monitored by the surgeon and the radiotherapist. The machine is then removed and the patient’s breast is reconstructed.
This new treatment is still in the trial stages but looks very promising.
Side effects of radiotherapy
Radiation therapy is relatively easy to tolerate, and the side effects are restricted to the area being treated. Rarely late cancers may be related to previous exposure to radiation.
Chemotherapy
Chemotherapy is the use of drugs to treat cancer. It is a systemic therapy; it affects the whole body by going through the bloodstream. Chemotherapy gets rid of any cancer cells that may have spread from the breast to another part of the body. It works by interfering with rapidly dividing cells characteristic of cancer.
The body's normal cells grow and divide in a controlled manner. Cancer cells, however, grow and divide in total chaos—without any control or logical order. Chemotherapy works by stopping the growth or multiplication of cancer cells, thereby killing them.
Before surgery, chemotherapy may be used both to reduce the size of the breast tumour and to destroy cancer cells. After surgery, chemotherapy works throughout the body to kill cancer cells that may have spread.
When used immediately or following surgery, chemotherapy is very effective. If the cancer cells have broken away from the primary tumour, there will be relatively young and small clusters located somewhere in the body. These single cells or small clusters have plenty of nutrients and oxygen, and they are dividing quite rapidly. This is perfect timing for chemotherapy because chemotherapy works best on rapidly dividing cells. Cancer cells are more sensitive to chemotherapy than normal cells.
Depending on the drug (or drugs) given there may be anywhere from four to eight monthly cycles of chemotherapy during an entire course of treatment.
Side effects of chemotherapy
The side effects of chemotherapy come about because cancer cells aren't the only rapidly dividing cells in the body. The cells in the blood, mouth, intestinal tract, nose, nails, genitals, and hair are also undergoing constant, rapid division. The chemotherapy is going to affect them too.
Healthy cells that are affected by the chemo have an advantage over cancer cells in that the body can repair the damage that chemotherapy does to normal cells. This explains why hair grows back, energy levels rise, and infections clear up. And while the body is fighting back, supportive medications can help control many of the side effects of chemotherapy.
While many side effects of chemotherapy fade quickly, others may take months or years to disappear completely.
Common side effects
The most common side effects of chemotherapy include nausea and vomiting, hair loss, fatigue and anemia, infections, mouth sores, taste and smell changes, diarrhea, menopause; fertility, and memory loss.
More serious side effects
Nerve function
The taxanes and platinum salts can cause temporary nerve damage or permanent neuropathy (irreversible loss of nerve function).
Heart function
Some drugs can have a toxic effect on the heart.
Leukaemia
In very rare cases, some drugs may cause a treatment-induced leukeamia (cancer of the blood cells).
Hormonal therapy
Hormonal therapy is another form of treatment for breast cancer. The goal is to protect the whole body from breast cancer cells that may have escaped the original tumour. Drugs are used to block the effects of hormones (such as estrogen and progesterone) that have the potential to promote the growth of breast cancer.
Hormone receptors are like ears or antennae on a cell. Hormones (mainly estrogen) attach themselves to the receptors. The hormones send signals through the receptors that tell the cells to grow. Breast cancer cells with hormone receptors grow and multiply when estrogen attaches to the receptors.
Breast cancer cells may have hormone receptors for estrogen, progesterone, or both. If the cancer cells have receptors, the tumour is called hormone-receptor-positive. If there are no hormone receptors, it is hormone-receptor-negative. Hormonal therapies work only if the cancer cells have estrogen or progesterone receptors. A pathology report will include the results of a test that shows whether the tumour is hormone-receptor positive or negative.
For breast cancers with hormone receptors, cell growth can be "turned on" by estrogen. This is why one way to stop or slow down the cancer growth is to stop this estrogen effect.
One way to stop or slow down cancer cell overgrowth is to block the hormone receptors so the growth signals can't get through to the cells. The most common hormonal therapy for breast cancer is the drug tamoxifen.
Tamoxifen
Tamoxifen is the best-known anti-estrogen therapy for fighting and preventing breast cancer. It is a powerful hormone therapy drug that can reduce the risk of breast cancer recurrence; decrease the chance of a new breast cancer starting; help keep bones strong; and help keep cholesterol down. How breast cancer responds to tamoxifen depends most on the presence of estrogen receptors.
Tamoxifen is a tablet and passes into the bloodstream from the stomach and circulates through the tissues of the body. If breast cancer cells are present, tamoxifen flows around them as well. If these cancer cells have estrogen receptors (about two-thirds do), tamoxifen slips into the receptor "locks," filling up a space that would normally be taken by the body's natural estrogen.
Because tamoxifen is such a weak estrogen, its estrogen signals don't stimulate very much cell growth. And because it has stolen the place away from more powerful estrogen, it blocks estrogen-stimulated cancer cell growth. In this way, tamoxifen acts like an "anti-estrogen."
Tamoxifen may also take the place of natural estrogen in the receptors of healthy breast cells. In that way it suppresses growth activity, and possibly prevents abnormal growth and the development of a totally new breast cancer.
Dominated by tamoxifen and deprived of normal estrogen stimulation breast cancer cells shrivel and wither like deflated balloons. As long as tamoxifen is hogging all the estrogen receptors, the cancer cells remain dormant and relatively harmless. After a long period of this suspended animation, the cancer cells may die. Tamoxifen may even cause breast cancer cells to destroy themselves, a process called apoptosis, or programmed cell death.
Tamoxifen may also prevent the formation of new blood vessels that the tumour needs to supply nutrients for growth. (This is called an "anti-angiogenic" effect, one that slows or stops blood vessel development.) Although this tamoxifen action would never be enough to halt the development of all blood vessels, it may be able to starve out some of the cancer cells.
Oncologists recommend that tamoxifen is taken for two to five years after successful treatment of an early breast cancer by surgery and radiotherapy. But at regular intervals all along the way it is necessary to re-evaluate the drug's potential side effects and benefits. For some women, the benefits do not continue for a full five years.
Tamoxifen can also reduce the risk of new breast cancers, this was discovered in studies of women taking tamoxifen to lower their risk of breast cancer recurrence. Now tamoxifen can be prescribed to prevent new breast cancers, not just to reduce recurrence of an old one.
Side effects of Tamoxifen
There is a risk that patients may experience some of the following side effects.
Blood clots (thrombosis)
If the patient has a history of blood clots tamoxifen is unlikely to be prescribed.
Endometrial cancer
The longer tamoxifen is taken, the higher the risk of developing a tamoxifen-related endometrial cancer. (But the risk is still low, less than 1%)
Uterine sarcoma
Women who take tamoxifen have a slightly higher risk than other women for developing uterine sarcoma. The risk for uterine sarcoma with tamoxifen is less than 1%.
Other uterine effects.
If there is a history of endometriosis tamoxifen can make this condition worse. Tamoxifen can also affect the uterus wall resulting in fibroids or bumpy irregularities in the uterine wall
Hot flushes
Tamoxifen can produce menopausal side effects that include vaginal dryness, mood changes, and hot flushes. About half of the women who take tamoxifen are affected by hot flashes.
Fertility
Tamoxifen should not be taken if the patient is trying to conceive, because the drug should not be taken during any stage of pregnancy. However no birth defects in people are known to have been caused by tamoxifen
Changes of the vagina
Nausea and vomiting
Weight gain
Mood swings and depression
Loss of energy
FTIs (farnesyl transferase inhibitors)
Another hormonal treatment for breast cancer are FTIs. Cancer cells require a certain degree of complex development and maturity to make receptors. Some cancer cells have few or no estrogen receptors and are therefore unlikely to respond to current anti-estrogen therapy. New studies are looking at drugs that target cell function that is independent of estrogen. One promising new class of drugs, called FTIs, work by weakening other chemical signals that stimulate cell growth and are not triggered by estrogen receptors.
Aromatase inhibitors
These drugs work by reducing the amount of estrogen in the body. The hormone estrogen delivers the growth signals to the hormone receptors. If there is less estrogen in the body, the hormone receptors receive fewer growth signals, and the cancer overgrowth can be stopped or controlled.
Aromatase inhibitors work only for post-menopausal women because they lower the amount of estrogen produced outside the ovaries. Before menopause, the ovaries produce most of a woman's estrogen, so reducing estrogen from other sources has little or no effect.
Further hormonal treatments
For pre-menopausal women, ovary removal or turning off the ovaries with drugs may be considered. In some cases, radiation of the ovaries can be used to turn off their production of estrogen or surgical removal.
Another way to get the growth of cancer cells under control is to reduce the number of receptors available to receive growth signals. Again drugs are in development to target this.
Side effects of hormonal therapies
Bone health is a major concern when estrogen is removed with any form of hormonal treatment. Women who go through the menopause as a result of breast cancer treatment can lose a significant amount of bone faster and at a much younger age than they would through the normal menopause. This is because the breast cancer treatments can significantly lower estrogen levels in a relatively short period of time.
Besides daily calcium, vitamin D, and weight-bearing exercise, there are medications that help keep bones strong in post-menopausal women.
Immune treatment
The drug Herceptin is the only immune treatment currently available for breast cancer and is still undergoing trials in certain stages of cancer. It helps the immune system fight the cancer by giving the body an antibody that can help slow down or stop the growth of cancer cells. Herceptin stops or slows the growth of certain breast cancer cells by blocking the chemical signals they need to grow. Herceptin works only against breast cancers that make too much of the HER2/neu, or HER2, protein. These cancers are called "HER2 positive." About one out of every four breast cancers is HER2 positive.
Herceptin can only be given intravenously, it is dripped into the body through a needle inserted into a vein. The first dose of Herceptin takes about 90 minutes. After that, it only takes about 30 minutes to get the other doses of Herceptin, which are usually given weekly. Studies have shown that Herceptin often works better in combination with different types of chemotherapy.
Unlike standard chemotherapy drugs, which are taken for a limited time, Herceptin is taken indefinitely in order to keep the breast cancer under control. It is not known yet if patients can stop taking the drug when they appear to be free of breast cancer for a certain period of time.
Side effects of immune therapy
Because it doesn't usually attach to other types of proteins, Herceptin rarely affects other cells in the body. This means that it causes few serious side effects.
World
- More than 1 million women are diagnosed with breast cancer every year.
- The highest rates of breast cancer are in the developed world and the lowest rates are in Africa and Asia.
- The Netherlands and the USA have the highest incidence of breast cancer.
- Denmark has the highest mortality rate closely followed by The Netherlands and the UK.
- China has the lowest incidence and mortality rate of breast cancer.
Europe
- Breast cancer is the most common cancer in women in Europe.
- 346,000 cases of breast cancer occur in Europe each year.
- The lowest European rates are in Eastern and Southern Europe.
- The highest rates are in Denmark, Belgium, Sweden and The Netherlands.
UK
- Breast cancer is the most common cancer in women in the UK.
- 100 new cases are diagnosed a day.
- Breast cancer is the 3rd most common cause of cancer death in the UK after lung and bowel cancer (men and women)
- One in nine women will develop breast cancer at some point in their lifetime, and four in five of them will be over 50.
- Men can also get breast cancer but it is very rare, with around 300 cases being diagnosed each year.
- Mortality from breast cancer in the UK has fallen by 22% since 1990, probably because of earlier detection and improved treatment. This trend is set to continue at a rate of around two per cent each year.
Trends
Breast cancer has been increasing in economically developed countries. The historically low rates in Eastern Europe and the Far East are beginning to rise rapidly
Socio-economic
Breast cancer is one of the few cancers to be more prevalent in affluent social classes. This is probably a reflection of several factors including reproductive history.
Survival
Survival rates for breast cancer in Europe have been improving for more than 20 years. Many more women are surviving breast cancer thanks to screening, specialised care and new drugs.
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