Definition of breast cancer
According to Saunders and Jassal (2009), breast cancer is cancer that forms in the cells of the breasts. After skin cancer, breast cancer is the most common cancer diagnosed in women in the world. Breast cancer can occur in both men and women, but it’s far more common in women. The first sign of breast cancer often is a breast lump or an abnormal mammogram. Breast cancer stages range from early, curable breast cancer to metastatic breast cancer, with a variety of breast cancer treatments. Male breast cancer is not uncommon and must be taken seriously.
Types of breast cancer
Lacroix (2006) stated that there are several types of breast cancer, but some of them are quite rare. According to him, in some cases a single breast tumour can be a combination of these types or be a mixture of invasive and in situ cancer.
Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS; also known as intraductal carcinoma) is considered non-invasive or pre-invasive breast cancer. DCIS means that cells that lined the ducts have changed to look like cancer cells. The difference between DCIS and invasive cancer is that the cells have not spread (invaded) through the walls of the ducts into the surrounding breast tissue. DCIS is considered a pre-cancer because some cases can go on to become invasive cancers. Right now, though, there is no good way to know for certain which cases will go on to become invasive cancers and which ones won’t.
About 1 in 5 new breast cancer cases will be DCIS. Nearly all women diagnosed at this early stage of breast cancer can be cured.
Lobular carcinoma in situ
In lobular carcinoma in situ (LCIS) cells that look like cancer cells grow in the lobules of the milk-producing glands of the breast, but they do not grow through the wall of the lobules.
Invasive (or infiltrating) ductal carcinoma
This is the most common type of breast cancer. Invasive (or infiltrating) ductal carcinoma (IDC) starts in a milk duct of the breast, breaks through the wall of the duct, and grows into the fatty tissue of the breast. At this point, it may be able to spread (metastasize) to other parts of the body through the lymphatic system and bloodstream. About 8 of 10 invasive breast cancers are infiltrating ductal carcinomas.
Invasive (or infiltrating) lobular carcinoma
Invasive lobular carcinoma (ILC) starts in the milk-producing glands (lobules). Like IDC, it can spread (metastasize) to other parts of the body. About 1 invasive breast cancer in 10 is an ILC. Invasive lobular carcinoma may be harder to detect by a mammogram than invasive ductal carcinoma.
Less common types of breast cancer
Inflammatory breast cancer: This uncommon type of invasive breast cancer accounts for about 1% to 3% of all breast cancers. Usually there is no single lump or tumour. Instead, inflammatory breast cancer (IBC) makes the skin on the breast look red and feels warm. It also may give the breast skin a thick, pitted appearance that looks a lot like an orange peel. Doctors now know that these changes are not caused by inflammation or infection, but by cancer cells blocking lymph vessels in the skin. The affected breast may become larger or firmer, tender, or itchy. In its early stages, inflammatory breast cancer is often mistaken for an infection in the breast (called mastitis) and treated as an infection with antibiotics. If the symptoms are caused by cancer, they will not improve, and a biopsy will find cancer cells. Because there is no actual lump, it might not show up on a mammogram, which can make it even harder to find it early. This type of breast cancer tends to have a higher chance of spreading and a worse outlook (prognosis) than typical invasive ductal or lobular cancer.
Triple-negative breast cancer: This term is used to describe breast cancers (usually invasive ductal carcinomas) whose cells lack oestrogen receptors and progesterone receptors, and do not have an excess of the HER2 protein on their surfaces. Breast cancers with these characteristics tend to occur more often in younger women and in African-American women. Triple-negative breast cancers tend to grow and spread more quickly than most other types of breast cancer. Because the tumour cells neither lack these certain receptors, neither hormone therapy nor drugs that target HER2 are effective treatments. Chemotherapy can still be useful, and is often recommended even for early-stage disease as it lowers the risk of the cancer coming back later.
Paget disease of the nipple: This type of breast cancer starts in the breast ducts and spreads to the skin of the nipple and then to the areola, the dark circle around the nipple. It is rare, accounting for only about 1% of all cases of breast cancer. The skin of the nipple and areola often appears crusted, scaly, and red, with areas of bleeding or oozing. The woman may notice burning or itching. Paget disease is almost always associated with either ductal carcinoma in situ (DCIS) or infiltrating ductal carcinoma. Treatment often requires mastectomy. If no lump can be felt in the breast tissue, and the biopsy shows DCIS but no invasive cancer, the outlook (prognosis) is excellent. If invasive cancer is present, the prognosis is not as good, and the cancer will need to be staged and treated like any other invasive cancer.
Phyllodes tumor: This very rare breast tumour develops in the stroma (connective tissue) of the breast, in contrast to carcinomas, which develop in the ducts or lobules. Other names for these tumours include phylloides tumour and cystosarcoma phyllodes. These tumours are usually benign but on rare occasions may be malignant. Benign phyllodes tumours are treated by removing the tumour along with a margin of normal breast tissue. A malignant phyllodes tumour is treated by removing it along with a wider margin of normal tissue, or by mastectomy. Surgery is often all that is needed, but these cancers might not respond as well to the other treatments used for more common breast cancers. When a malignant phyllodes tumor has spread, it can be treated with the chemotherapy given for soft-tissue sarcomas.
Angiosarcoma: This form of cancer starts in cells that line blood vessels or lymph vessels. It rarely occurs in the breasts. When it does, it usually develops as a complication of previous radiation treatments. This is an extremely rare complication of breast radiation therapy that can develop about 5 to 10 years after radiation. Angiosarcoma can also occur in the arms of women who develop lymphedema as a result of lymph node surgery or radiation therapy to treat breast cancer. These cancers tend to grow and spread quickly. Treatment is generally the same as for other sarcomas.
Special types of invasive breast carcinoma
There are some special types of breast cancer that are sub-types of invasive carcinoma. These are often named after features seen when they are viewed under the microscope, like the ways the cells are arranged.
Some of these may have a better prognosis than standard infiltrating ductal carcinoma. These include:
- Adenoid cystic (or adenocystic) carcinoma
- Low-grade adenosquamous carcinoma (this is a type of metaplastic carcinoma)
- Medullary carcinoma
- Mucinous (or colloid) carcinoma
- Papillary carcinoma
- Tubular carcinoma
Some sub-types have the same or maybe worse prognosis than standard infiltrating ductal carcinoma. These include:
- Metaplastic carcinoma (most types, including spindle cell and squamous)
- Micropapillary carcinoma
- Mixed carcinoma (has features of both invasive ductal and lobular)
In general, all of these sub-types are still treated like standard infiltrating ductal carcinoma.
Causes of breast cancer
Hartmann, Schaid, Woods, Crotty and Myers (1999) highlighted that it is not clear what causes breast cancer. Doctors know that breast cancer occurs when some breast cells begin growing abnormally. These cells divide more rapidly than healthy cells do and continue to accumulate, forming a lump or mass. The cells may spread (metastasize) through your breast to your lymph nodes or to other parts of your body.
Breast cancer most often begins with cells in the milk-producing ducts (invasive ductal carcinoma). Breast cancer may also begin in the glandular tissue called lobules (invasive lobular carcinoma) or in other cells within the breast.
Researchers have identified things that can increase your risk of breast cancer. But it’s not clear why some people who have no risk factors develop cancer, yet other people with risk factors never do. It’s likely that breast cancer is caused by a complex interaction of your genetic makeup and your environment.
Inherited breast cancer
Doctors estimate that only 5 to 10 percent of breast cancers are linked to gene mutations passed through generations of a family. A number of inherited mutated genes that can increase the likelihood of breast cancer have been identified. The most common are breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2), both of which increase the risk of both breast and ovarian cancer.
If you have a strong family history of breast cancer or other cancers, blood tests may help identify mutations in BRCA or other genes that are being passed through your family.
Symptoms of breast cancer
Nelson, Smith, and Griffin (2013) stated that in its early stages, breast cancer usually has no symptoms. As a tumour develops, you may note the following signs:
- A lump in the breast or underarm that persists after your menstrual cycle. This is often the first apparent symptom of breast cancer. Lumps associated with breast cancer are usually painless, although some may cause a prickly sensation. Lumps are usually visible on a mammogram long before they can be seen or felt.
- Swelling in the armpit.
- Pain or tenderness in the breast. Although lumps are usually painless, pain or tenderness can be a sign of breast cancer.
- A noticeable flattening or indentation on the breast, which may indicate a tumor that cannot be seen or felt.
- Any change in the size, contour, texture, or temperature of the breast. A reddish, pitted surface like the skin of an orange could be a sign of advanced breast cancer.
- A change in the nipple, such as a nipple retraction, dimpling, itching, a burning sensation, or ulceration. A scaly rash of the nipple is symptomatic of Paget’s disease, which may be associated with an underlying breast cancer.
- Unusual discharge from the nipple that may be clear, bloody, or another colour. It’s usually caused by benign conditions but could be due to cancer in some cases.
- A marble-like area under the skin.
- An area that is distinctly different from any other area on either breast.
Risk factors of breast cancer
A breast cancer risk factor is anything that makes it more likely you’ll get breast cancer. But having one or even several breast cancer risk factors doesn’t necessarily mean you’ll develop breast cancer. Many women who develop breast cancer have no known risk factors other than simply being women.
Factors that are associated with an increased risk of breast cancer according to Kahlenborn, Modugno, Potter and Severs (2006)include:
- Being female: Women are much more likely than men are to develop breast cancer.
- Increasing age: Your risk of breast cancer increases as you age.
- A personal history of breast cancer: If you’ve had breast cancer in one breast, you have an increased risk of developing cancer in the other breast.
- A family history of breast cancer: If your mother, sister or daughter was diagnosed with breast cancer, particularly at a young age, your risk of breast cancer is increased. Still, the majority of people diagnosed with breast cancer have no family history of the disease.
- Inherited genes that increase cancer risk: Certain gene mutations that increase the risk of breast cancer can be passed from parents to children. The most common gene mutations are referred to as BRCA1 and BRCA2. These genes can greatly increase your risk of breast cancer and other cancers, but they don’t make cancer inevitable.
- Radiation exposure: If you received radiation treatments to your chest as a child or young adult, your risk of breast cancer is increased.
- Obesity: Being obese increases your risk of breast cancer.
- Beginning your period at a younger age: Beginning your period before age 12 increases your risk of breast cancer.
- Beginning menopause at an older age: If you began menopause at an older age, you’re more likely to develop breast cancer.
- Having your first child at an older age: Women who give birth to their first child after age 35 may have an increased risk of breast cancer.
- Having never been pregnant: Women who have never been pregnant have a greater risk of breast cancer than do women who have had one or more pregnancies.
- Postmenopausal hormone therapy: Women who take hormone therapy medications that combine estrogen and progesterone to treat the signs and symptoms of menopause have an increased risk of breast cancer. The risk of breast cancer decreases when women stop taking these medications.
- Drinking alcohol: Drinking alcohol increases the risk of breast cancer.
Test and diagnosis of breast cancer
Biesheuvel, Weigel, and Heindel (2011) identified tests and procedures used to diagnose breast cancer to include:
- Breast exam: Your doctor will check both of your breasts, feeling for any lumps or other abnormalities.
- Mammogram: A mammogram is an X-ray of the breast. Mammograms are commonly used to screen for breast cancer. If an abnormality is detected on a screening mammogram, your doctor may recommend a diagnostic mammogram to further evaluate that abnormality.
- Breast ultrasound: Ultrasound uses sound waves to produce images of structures deep within the body. Ultrasound may help distinguish between a solid mass and a fluid-filled cyst.
- Removing a sample of breast cells for testing (biopsy): Biopsy samples are sent to a laboratory for analysis where experts determine whether the cells are cancerous. A biopsy sample is also analyzed to determine the type of cells involved in the breast cancer, the aggressiveness (grade) of the cancer, and whether the cancer cells have hormone receptors or other receptors that may influence your treatment options.
- Breast magnetic resonance imaging (MRI): An MRI machine uses a magnet and radio waves to create pictures of the interior of your breast. Before a breast MRI, you receive an injection of dye.
According to them, other tests and procedures may be used depending on your situation.
Staging breast cancer
Once your doctor has diagnosed your breast cancer, he or she works to establish the extent (stage) of your cancer. Your cancer’s stage helps determine your prognosis and the best treatment options. Complete information about your cancer’s stage may not be available until after you undergo breast cancer surgery.
Tests and procedures used to stage breast cancer may include:
- Blood tests, such as a complete blood count
- Mammogram of the other breast to look for signs of cancer
- Breast MRI
- Bone scan
- Computerized tomography (CT) scan
- Positron emission tomography (PET) scan
Not all women will need all of these tests and procedures. Your doctor selects the appropriate tests based on your specific circumstances.
Breast cancer stages range from 0 to IV, with 0 indicating cancer that is very small and noninvasive. Stage IV breast cancer, also called metastatic breast cancer, indicates cancer that has spread to other areas of the body.
Prevention of breast cancer
Making changes in your daily life may help reduce your risk of breast cancer according to Reeder and Vogel (2008), try to:
- Ask your doctor about breast cancer screening: Discuss with your doctor when to begin breast cancer screening exams and tests, such as clinical breast exams and mammograms. Talk to your doctor about the benefits and risks of screening. Together you can decide what breast cancer screening strategies are right for you.
- Become familiar with your breasts through breast self-exams: Ask your doctor to show you how to do a breast self-exam to check for any lumps or other unusual signs in your breasts. A breast self-exam can’t prevent breast cancer, but it may help you to better understand the normal changes that your breasts undergo and identify any unusual signs and symptoms.
- Drink alcohol in moderation, if at all: Limit the amount of alcohol you drink to less than one drink a day, if you choose to drink.
- Exercise most days of the week: Aim for at least 30 minutes of exercise on most days of the week. If you haven’t been active lately, ask your doctor whether it’s OK and start slowly.
- Limit postmenopausal hormone therapy: Combination hormone therapy may increase the risk of breast cancer. Talk with your doctor about the benefits and risks of hormone therapy. Some women experience bothersome signs and symptoms during menopause and, for these women, the increased risk of breast cancer may be acceptable in order to relieve menopause signs and symptoms. To reduce the risk of breast cancer, use the lowest dose of hormone therapy possible for the shortest amount of time.
- Maintain a healthy weight: If your weight is healthy, work to maintain that weight. If you need to lose weight, ask your doctor about healthy strategies to accomplish this. Reduce the number of calories you eat each day and slowly increase the amount of exercise.
Breast cancer risk reduction for women with a high risk
If your doctor has assessed your family history and other factors and determined that you may have an increased risk of breast cancer, options to reduce your risk include:
- Preventive medications (chemoprevention). Estrogen-blocking medications may help reduce the risk of breast cancer. Options include tamoxifen and raloxifene (Evista). Aromatase inhibitors have also shown some promise in reducing the risk of breast cancer in women with a high risk.
These medications carry a risk of side effects, so doctors reserve these medications for women who have a very high risk of breast cancer. Discuss the benefits and risks with your doctor.
- Preventive surgery. Women with a very high risk of breast cancer may choose to have their healthy breasts surgically removed (prophylactic mastectomy). They may also choose to have their healthy ovaries removed (prophylactic oophorectomy) to reduce the risk of both breast cancer and ovarian cancer.
Dietary management of breast cancer
According to Blackburn and Wang (2007), eating well is very essential for the effective management of breast cancer. This will help you:
- Stay healthy
- Maintain energy
- Get the right nutrients
- Prevent unexpected weight gain
While you are having chemotherapy, radiation therapy, or both, follow these tips:
- Drink at least 8 glasses of non-caloric (i.e., water, seltzer, tea) or low-calorie beverages each day. Not drinking enough liquids can cause lightheadedness, dizziness, nausea, constipation, fatigue, and urinary tract infection.
- Avoid skipping meals. Try eating small, regularly spaced meals throughout the day.
- Choose moderate sized portions of lean, protein-rich foods at most meals. These include: Non-fat or low-fat dairy products
- White-meat poultry or lean meats
- A variety of fish
- Choose fiber-rich foods daily, such as leafy greens, fruits, beans, and whole grains.
- Limit your intake of refined sugars, such as candy, juice, and regular soda. Too much refined sugar and sweets can cause fatigue due to sharp changes in blood sugar levels. They can also add too many calories to your diet.
- Ask your doctor before you take any vitamins, minerals, herbs, or other dietary supplements. You can take calcium and vitamin D supplements. Discuss this with your doctor, nurse, or dietitian.
- Methotrexate (Trexall™) and capecitabine (Xeloda®) may interact with folic acid. Folic acid is a nutrient found in most multivitamins and in some fortified foods. If you are taking these medications, speak with your doctor, nurse, or dietitian.
- Limit your intake of alcohol or stop drinking it altogether. If you have any questions, speak with your healthcare team.
Biesheuvel, C., Weigel, S. and Heindel, W. (2011). “Mammography Screening: Evidence, History and Current Practice in Germany and Other European Countries.”. Breast care (Basel, Switzerland) 6 (2): 104–109.
Blackburn, G.L. and Wang, K.A. (2007). “Dietary fat reduction and breast cancer outcome: results from the Women’s Intervention Nutrition Study (WINS).”. The American journal of clinical nutrition 86 (3): s878–81.
Hartmann, L.C., Schaid, D.J., Woods, J.E., Crotty, T.P. and Myers, J.L. (1999). “Efficacy of bilateral prophylactic mastectomy in women with a family history of breast cancer”. N Engl J Med 340 (2): 77–84.
Kahlenborn, C., Modugno, F., Potter, D.M. and Severs, W.B. (2006). “Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis.”. Mayo Clinic proceedings. Mayo Clinic 81 (10): 1290–302.
Lacroix, M. (2006). “Significance, detection and markers of disseminated breast cancer cells”. Endocrine-related Cancer 13 (4): 1033–67
Nelson, H.D., Smith, M.E. and Griffin, J.C.(2013). “Use of medications to reduce risk for primary breast cancer: a systematic review for the U.S. Preventive Services Task Force.”. Annals of Internal Medicine 158 (8): 604–14.
Reeder, J.G. and Vogel, V.G. (2008). “Breast cancer prevention.”. Cancer treatment and research 141: 149–64.
Saunders, C. & Jassal, S. (2009). Breast cancer (1. ed. ed.). Oxford: Oxford University Press.