Breast Cancer: Causes, Symptoms and Treatments
Breast cancer usually starts off in the inner lining of milk ducts or the lobules that supply them with milk. A malignant tumor can spread to other parts of the body. A breast cancer that started off in the lobules is known as lobular carcinoma, while one that developed from the ducts is called ductal carcinoma.
The vast majority of breast cancer cases occur in females. This article focuses on breast cancer in women.
Breast cancer rates are much higher in developed nations compared to developing ones. There are several reasons for this, with possibly life-expectancy being one of the key factors - breast cancer is more common in elderly women; women in the richest countries live much longer than those in the poorest nations. The different lifestyles and eating habits of females in rich and poor countries are also contributory factors, experts believe.
According to the National Cancer Institute, 232,340 female breast cancers and 2,240 male breast cancers are reported in the USA each year, as well as about 39,620 deaths caused by the disease.
Contents of this article:
- Breast anatomy and breast cancer symptoms
- Causes and diagnosis
- Treatments and prevention
- Latest research
The anatomy of a female breast
1. Chest wall. 2. Pectoralis muscles. 3. Lobules (glands that make milk). 4. Nipple surface. 5. Areola. 6. Lactiferous duct tube that carries milk to the nipple. 7. Fatty tissue. 8. Skin.
Image by Patrick J. Lynch and Morgoth666
The breast, like any other part of the body, consists of billions of microscopic cells. These cells multiply in an orderly fashion - new cells are made to replace the ones that died.
In cancer, the cells multiply uncontrollably, and there are too many cells, progressively more and more than there should be.
Cancer that begins in the lactiferous duct (milk duct), known as ductal carcinoma, is the most common type. Cancer that begins in the lobules, known as lobular carcinoma, is much less common.
Symptoms of breast cancer
Some of the possible early signs of breast cancer
The first symptoms of breast cancer are usually an area of thickened tissue in the woman's breast, or a lump. The majority of lumps are not cancerous; however, women should get them checked by a health care professional.
Women who detect any of the following signs or symptoms should tell their doctor :
- A lump in a breast
- A pain in the armpits or breast that does not seem to be related to the woman's menstrual period
- Pitting or redness of the skin of the breast; like the skin of an orange
- A rash around (or on) one of the nipples
- A swelling (lump) in one of the armpits
- An area of thickened tissue in a breast
- One of the nipples has a discharge; sometimes it may contain blood
- The nipple changes in appearance; it may become sunken or inverted
- The size or the shape of the breast changes
- The nipple-skin or breast-skin may have started to peel, scale or flake.
Causes of breast cancer
Experts are not definitively sure what causes breast cancer. It is hard to say why one person develops the disease while another does not. We know that some risk factors can impact on a woman's likelihood of developing breast cancer. These are:
1) Getting older
The older a woman gets, the higher is her risk of developing breast cancer; age is a risk factor. Over 80% of all female breast cancers occur among women aged 50+ years (after the menopause).
2) Genetics
Women who have a close relative who has/had breast or ovarian cancer are more likely to develop breast cancer. If two close family members develop the disease, it does not necessarily mean they shared the genes that make them more vulnerable, because breast cancer is a relatively common cancer.
The majority of breast cancers are not hereditary.
Women who carry the BRCA1 and BRCA2 genes have a considerably higher risk of developing breast and/or ovarian cancer. These genes can be inherited. TP53, another gene, is also linked to greater breast cancer risk.
3) A history of breast cancer
Women who have had breast cancer, even non-invasive cancer, are more likely to develop the disease again, compared to women who have no history of the disease.
4) Having had certain types of breast lumps
Women who have had some types of benign (non-cancerous) breast lumps are more likely to develop cancer later on. Examples include atypical ductal hyperplasia or lobular carcinoma in situ.
5) Dense breast tissue
Women with more dense breast tissue have a greater chance of developing breast cancer.
6) Estrogen exposure
Women who started having periods earlier or entered menopause later than usual have a higher risk of developing breast cancer. This is because their bodies have been exposed to estrogen for longer. Estrogen exposure begins when periods start, and drops dramatically during the menopause.
7) Obesity
Post-menopausal obese and overweight women may have a higher risk of developing breast cancer. Experts say that there are higher levels of estrogen in obese menopausal women, which may be the cause of the higher risk.
8) Height
Taller-than-average women have a slightly greater likelihood of developing breast cancer than shorter-than-average women. Experts are not sure why.
9) Alcohol consumption
The more alcohol a woman regularly drinks, the higher her risk of developing breast cancer is. The Mayo Clinic says that if a woman wants to drink, she should not exceed one alcoholic beverage per day.
10) Radiation exposure
Undergoing X-rays and CT scans may raise a woman's risk of developing breast cancer slightly. Scientists at the Memorial Sloan-Kettering Cancer Center found that women who had been treated with radiation to the chest for a childhood cancer have a higher risk of developing breast cancer.
11) HRT (hormone replacement therapy)
Both forms, combined and estrogen-only HRT therapies may increase a woman's risk of developing breast cancer slightly. Combined HRT causes a higher risk.
12) Certain jobs
French researchers found that women who worked at night prior to a first pregnancy had a higher risk of eventually developing breast cancer.
Canadian researchers found that certain jobs, especially those that bring the human body into contact with possible carcinogens and endocrine disruptors are linked to a higher risk of developing breast cancer. Examples include bar/gambling, automotive plastics manufacturing, metal-working, food canning and agriculture. They reported their findings in the November 2012 issue of Environmental Health.
Cosmetic implants may undermine breast cancer survival
Women who have cosmetic breast implants and develop breast cancer may have a higher risk of dying prematurely form the disease compared to other females, researchers from Canada reported in the BMJ (British Medical Journal) (May 2013 issue).
The team looked at twelve peer-reviewed articles on observational studies which had been carried out in Europe, the USA and Canada.
Experts had long-wondered whether cosmetic breast implants might make it harder to spot malignancy at an early stage, because they produce shadows on mammograms.
In this latest study, the authors found that a woman with a cosmetic breast implant has a 25% higher risk of being diagnosed with breast cancer when the disease has already advanced, compared to those with no implants.
Women with cosmetic breast implants who are diagnosed with breast cancer have a 38% higher risk of death from the disease, compared to other patients diagnosed with the same disease who have no implants, the researchers wrote.
After warning that there were some limitations in the twelve studies they looked at, the authors concluded "Further investigations are warranted into the long term effects of cosmetic breast implants on the detection and prognosis of breast cancer, adjusting for potential confounders."
Recent developments on breast cancer causes
- Breast cancer less likely to recur in women with history of breastfeeding
- 'Rogue' milk-producing protein helps breast cancer spread
- Study links high sugar intake to increased risk of breast cancer
- Alcohol triggers breast cancer-causing gene
Invasive and non-invasive breast cancer
Invasive breast cancer - the cancer cells break out from inside the lobules or ducts and invade nearby tissue. With this type of cancer, the abnormal cells can reach the lymph nodes, and eventually make their way to other organs (metastasis), such as the bones, liver or lungs. The abnormal (cancer) cells can travel through the bloodstream or the lymphatic system to other parts of the body; either early on in the disease, or later.
Non-invasive breast cancer - this is when the cancer is still inside its place of origin and has not broken out. Lobular carcinoma in situ is when the cancer is still inside the lobules, while ductal carcinoma in situ is when they are still inside the milk ducts. "In situ" means "in its original place". Sometimes, this type of breast cancer is called "pre-cancerous"; this means that although the abnormal cells have not spread outside their place of origin, they can eventually develop into invasive breast cancer.
Diagnosing breast cancer
Women are usually diagnosed with breast cancer after a routine breast cancer screening, or after detecting certain signs and symptoms and seeing their doctor about them.
If a woman detects any of the breast cancer signs and symptoms described above, she should speak to her doctor immediately. The doctor, often a primary care physician (general practitioner, GP) initially, will carry out a physical exam, and then refer the patient to a specialist if he/she thinks further assessment is needed.
Below are examples of diagnostic tests and procedures for breast cancer:
1) Breast exam
The physician will check both the patient's breasts, looking out for lumps and other possible abnormalities, such as inverted nipples, nipple discharge, or change in breast shape. The patient will be asked to sit/stand with her arms in different positions, such as above her head and by her sides.
2) X-ray (mammogram)
Commonly used for breast cancer screening. If anything unusual is found, the doctor may order a diagnostic mammogram.
Breast cancer screening has become a controversial subject over the last few years. Experts, professional bodies, and patient groups cannot currently agree on when mammography screening should start and how often it should occur. Some say routine screening should start when the woman is 40 years old, others insist on 50 as the best age, and a few believe that only high-risk groups should have routine screening.
In July, 2012, The American Medical Association said that women should be eligible for screening mammography from the age of 40, and it should be covered by insurance.
In a Special Report in The Lancet (October 30th, 2012 issue), a panel of experts explained that breast cancer screening reduces the risk of death from the disease. However, they added that it also creates more cases of false-positive results, where women end up having unnecessary biopsies and harmless tumors are surgically removed.
In another study, carried out by scientists at the The Dartmouth Institute for Healthy Policy & Clinical Practice in Lebanon, N.H., and reported in the New England Journal of Medicine (November 2012 issue), researchers found that mammograms do not reduce breast cancer death rates.
3) 2D combined with 3D mammograms
3D mammograms, when used in collaboration with regular 2D mammograms were found to reduce the incidence of false positives, researchers from the University of Sydney's School of Public Health, Australia, reported in The Lancet Oncology.
The researchers screened 7,292 adult females, average age 58 years. Their initial screening was done using 2D mammograms, and then they underwent a combination of 2D and 3D mammograms.
Professor Nehmat Houssami and team found 59 cancers in 57 patients. 66% of the cancers were detected in both 2D and combined 2D/3D screenings. However, 33% of them were only detected using the 2D plus 3D combination.
The team also found that 2D plus 3D combination screenings were linked to a much lower number of false positives. When using just 2D screenings there were 141 false positives, compared to 73 using the 2D plus 3D combination.
Prof. Houssami said "Although controversial, mammography screening is the only population-level early detection strategy that has been shown to reduce breast cancer mortality in randomized trials. Irrespective of which side of the mammography screening debate one supports, efforts should be made to investigate methods that enhance the quality of, and hence potential benefit from, mammography screening.
We have shown that integrated 2D and 3D mammography in population breast-cancer screening increases detection of breast cancer and can reduce false-positive recalls depending on the recall strategy. Our results do not warrant an immediate change to breast-screening practice, instead, they show the urgent need for randomised controlled trials of integrated 2D and 3D versus 2D mammography."
4) Breast ultrasound
This type of scan may help doctors decide whether a lump or abnormality is a solid mass or a fluid-filled cyst.
5) Biopsy
A sample of tissue from an apparent abnormality, such as a lump, is surgically removed and sent to the lab for analysis. It the cells are found to be cancerous, the lab will also determine what type of breast cancer it is, and the grade of cancer (aggressiveness). Scientists from the Technical University of Munich found that for an accurate diagnosis, multiple tumor sites need to be taken.
6) Breast MRI (magnetic resonance imaging) scan
A dye is injected into the patient. This type of scan helps the doctor determine the extent of the cancer. Researchers from the University of California in San Francisco found that MRI provides a useful indication of a breast tumor's response to pre-surgical chemotherapy much earlier than possible through clinical examination.
Breast cancer staging Staging describes the extent of the cancer in the patient's body and is based on whether it is invasive or non-invasive, how large the tumor is, whether lymph nodes are involved and how many, and whether it has metastasized (spread to other parts of the body).
A cancer's stage is a crucial factor in deciding what treatment options to recommend, and in determining the patient's prognosis.
Staging is done after cancer is diagnosed. To do the staging, the doctor may order several different tests, including blood tests, a mammogram, a chest X-ray, a bone scan, a CT scan, or a PET scan.
Breast Cancer: Treatments and Prevention
Treatments for breast cancer
A multidisciplinary team will be involved in a breast cancer patient's treatment. The team may consists of an oncologist, radiologist, specialist cancer surgeon, specialist nurse, pathologist, radiologist, radiographer, and reconstructive surgeon. Sometimes the team may also include an occupational therapist, psychologist, dietitian, and physical therapy.
The team will take into account several factors when deciding on the best treatment for the patient, including: - The type of breast cancer
- The stage and grade of the breast cancer - how large the tumor is, whether or not it has spread, and if so how far
- Whether or not the cancer cells are sensitive to hormones
- The patient's overall health
- The age of the patient (has she been through the menopause?)
- The patient's own preferences.
- Radiation therapy (radiotherapy)
- Surgery
- Biological therapy (targeted drug therapy)
- Hormone therapy
- Chemotherapy.
Surgery
- Lumpectomy - surgically removing the tumor and a small margin of healthy tissue around it. In breast cancer, this is often called breast-sparing surgery. This type of surgery may be recommended if the tumor is small and the surgeon believes it will be easy to separate from the tissue around it.
- Mastectomy - surgically removing the breast. Simple mastectomy involves removing the lobules, ducts, fatty tissue, nipple, areola, and some skin. Radical mastectomy means also removing muscle of the chest wall and the lymph nodes in the armpit.
- Sentinel node biopsy - one lymph node is surgically removed. If the breast cancer has reached a lymph node it can spread further through the lymphatic system into other parts of the body.
- Axillary lymph node dissection - if the sentinel node was found to have cancer cells, the surgeon may recommend removing several nymph nodes in the armpit.
- Breast reconstruction surgery - a series of surgical procedures aimed at recreating a breast so that it looks as much as possible like the other breast. This procedure may be carried out at the same time as a mastectomy. The surgeon may use a breast implant, or tissue from another part of the patient's body.
Radiation therapy (radiotherapy)
Controlled doses of radiation are targeted at the tumor to destroy the cancer cells. Usually, radiotherapy is used after surgery, as well as chemotherapy to kill off any cancer cells that may still be around. Typically, radiation therapy occurs about one month after surgery or chemotherapy. Each session lasts a few minutes; the patient may require three to five sessions per week for three to six weeks.The type of breast cancer the woman has will decide what type of radiation therapy she may have to undergo. In some cases, radiotherapy is not needed.
Radiation therapy types include:
- Breast radiation therapy - after a lumpectomy, radiation is administered to the remaining breast tissue
- Chest wall radiation therapy - this is applied after a mastectomy
- Breast boost - a high-dose of radiation therapy is applied to where the tumor was surgically removed. The appearance of the breast may be altered, especially if the patient's breasts are large.
- Lymph nodes radiation therapy - the radiation is aimed at the axilla (armpit) and surrounding area to destroy cancer cells that have reached the lymph nodes
- Breast brachytherapy - scientists at UC San Diego Moores Cancer Center revealed that patients with early-stage breast cancer in the milk ducts which has not spread, seem to benefit from undergoing breast brachytherapy with a strut-based applicator. This 5-day treatment is given to patients after they have undergone lumpectomy surgery. The researchers found that women who received strut-based breast brachytherapy had lower recurrence rates, as well as fewer and less severe side effects.
Chemotherapy
Medications are used to kill the cancer cells - these are called cytotoxic drugs. The oncologist may recommend chemotherapy if there is a high risk of cancer recurrence, or the cancer spreading elsewhere in the body. This is called adjuvant chemotherapy.
Chemotherapy may also be administered if the cancer has metastasized - spread to other parts of the body. Chemotherapy is also useful in reducing some of the symptoms caused by cancer.
Chemotherapy may help stop estrogen production. Estrogen can encourage the growth of some breast cancers.
Side effects of chemotherapy may include nausea, vomiting, loss of appetite, fatigue, sore mouth, hair loss, and a slightly higher susceptibility to infections. Many of these side effects can be controlled with medications the doctor can prescribe. Women over 40 may enter early menopause.
Protecting female fertility - Scientists have designed a way of aggressively attacking cancer with an arsenic-based chemo medication, which is much gentler on the ovaries. The researchers, from Northwestern University Feinberg School of Medicine in Chicago, believe their novel method will help protect the fertility of female patients undergoing cancer treatment.
Hormone therapy (hormone blocking therapy)
Hormone therapy is used for breast cancers that are sensitive to hormones. These types of cancer are often referred to as ER positive (estrogen receptor positive) and PR positive (progesterone receptor positive) cancers. The aim is to prevent cancer recurrence. Hormone blocking therapy is usually used after surgery, but may sometimes be used beforehand to shrink the tumor.If for health reasons, the patient cannot undergo surgery, chemotherapy or radiotherapy, hormone therapy may be the only treatment she receives.
Hormone therapy will have no effect on cancers that are not sensitive to hormones.
Hormone therapy usually lasts up to five years after surgery.
The following hormone therapy medications may be used:
- Tamoxifen - prevents estrogen from binding to ER-positive cancer cells. Side effects may include changes in periods, hot flashes, weight gain, headaches, nausea, vomiting, fatigue, and aching joints.
- Aromatase inhibitors - this type of medication may be offered to women who have been through the menopause. It blocks aromatase. Aromatase helps estrogen production after the menopause. Before the menopause, a woman's ovaries produce estrogen. Examples of aromatase inhibitors include letrozole, exemestane, and anastrozole. Side effects may include nausea, vomiting, fatigue, skin rashes, headaches, bone pain, aching joints, loss of libido, sweats, and hot flashes. Ovarian ablation or suppression - pre-menopausal women produce estrogen in their ovaries. Ovarian ablation or suppression stop the ovaries from producing estrogen. Ablation is done either through surgery or radiation therapy - the woman's ovaries will never work again, and she will enter the menopause early.
A luteinising hormone-releasing hormone agonist (LHRHa) drug called Goserelin will suppress the ovaries. The patient's periods will stop during treatment, but will start again when she stops taking Goserelin. Women of menopausal age (about 50 years) will probably never start having periods again. Side effects may include mood changes, sleeping problems, sweats, and hot flashes.
Biological treatment (targeted drugs)
- Trastuzumab (Herceptin) - this monoclonal antibody targets and destroys cancer cells that are HER2-positive. Some breast cancer cells produce large amounts of HER2 (growth factor receptor 2); Herceptin targets this protein. Possible side effects may include skin rashes, headaches, and/or heart damage.
- Lapatinib (Tykerb) - this drug targets the HER2 protein. It is also used for the treatment of advanced metastatic breast cancer. Tykerb is used on patients who did not respond well to Herceptin. Side effects include painful hands, painful feet, skin rashes, mouth sores, extreme tiredness, diarrhea, vomiting, and nausea.
- Bevacizumab (Avastin) - stops the cancer cells from attracting new blood vessels, effectively causing the tumor to be starved of nutrients and oxygen. Side effects may include congestive heart failure, hypertension (high blood pressure), kidney damage, heart damage, blood clots, headaches, mouth sores. Although not approved by the FDA for this use, doctors may prescribe it "off-label". Using this drug for breast cancer is controversial. In 2011, the FDA said that Avastin is neither effective nor safe for breast cancer.
- Low dose aspirin - research carried out on laboratory mice and test tubes has suggested that regular low-dose aspirin may halt the growth and spread of breast cancer. Cancer campaigners cautioned that although the current results show great promise, this research is at a very early stage and has yet to be shown to be effective on humans.
Preventing breast cancer
Some lifestyle changes can help significantly reduce a woman's risk of developing breast cancer.- Alcohol consumption - women who drink in moderation, or do not drink alcohol at all, are less likely to develop breast cancer compared to those who drink large amounts regularly. Moderation means no more than one alcoholic drink per day.
- Physical exercise - exercising five days a week has been shown to reduce a woman's risk of developing breast cancer. Researchers from the University of North Carolina Gillings School of Global Public Health in Chapel Hill reported that physical activity can lower breast cancer risk, whether it be either mild or intense, or before/after menopause. However, considerable weight gain may negate these benefits.
- Diet - some experts say that women who follow a healthy, well-balanced diet may reduce their risk of developing breast cancer. A study published in BMJ (June 2013 issue) found that women who regularly consumed fish and marine n-3 polyunsaturated fatty acids had a 14% lower risk of developing breast cancer, compared to other women. The authors, from Zhejiang University, China, explained that a "regular consumer" should be eating at least 1 or 2 portions of oily fish per week (tuna, salmon, sardines, etc).
- Postmenopausal hormone therapy - limiting hormone therapy may help reduce the risk of developing breast cancer. It is important for the patient to discuss the pros and cons thoroughly with her doctor.
- Bodyweight - women who have a healthy bodyweight have a considerably lower chance of developing breast cancer compared to obese and overweight females.
- Women at high risk of breast cancer - the doctor may recommend estrogen-blocking drugs, including tamoxifen and raloxifene. Tamoxifen may raise the risk of uterine cancer. Preventive surgery is a possible option for women at very high risk.
- Breast cancer screening - patients should discuss with their doctor when to start breast cancer screening exams and tests.
- Breastfeeding - women who breastfeed run a lower risk of developing breast cancer compared to other women. A team of researchers from the University of Granada in Spain reported in the Journal of Clinical Nursing that breastfeeding for at least six months reduces the risk of early breast cancer. This only applies to non-smoking women, the team added. They found that mothers who breastfed for six months or more, if they developed breast cancer, did so on average ten years later than other women. Did you find this article helpful?
All you need to about Breast cancer
Reviewed by Adecy Julio
on
June 30, 2016
Rating:
Reviewed by Adecy Julio
on
June 30, 2016
Rating:
Posts
No comments: