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Breast cancer is the most common invasive cancer in females worldwide. It accounts for 16% of all female cancers and 22.9% of invasive cancers in women. 18.2% of all cancer deaths worldwide, including both males and females, are from breast cancer.
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. We also have an article about male breast cancer.
Anatomy of breast cancer
A mature human female's breast consists of fat, connective tissue and thousands of lobules – tiny glands which produce milk. The milk of a breastfeeding mother goes through tiny ducts (tubes) and is delivered through the nipple.
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.
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:
§ 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).
§ 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.
§ 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.
§ 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.
§ 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.
§ 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.
§ Height – taller-than-average women have a slightly greater likelihood of developing breast cancer than shorter-than-average women. Experts are not sure why.
- Alcohol consumption – the more alcohol a woman regularly drinks, the higher her risk of developing breast cancer is.
- Radiation exposure – undergoing X-rays and CT scans may raise a woman's risk of developing breast cancer slightly.
- 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.
Symptoms of breast cancer
A symptom is only felt by the patient, and is described to the doctor or nurse, such as a headache or pain. A sign is something the patient and others can detect, for example, a rash or swelling.
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.
- 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
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:
- 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.
- X-ray (mammogram) – commonly used for breast cancer screening. If anything unusual is found, the doctor may order a diagnostic mammogram.
- Breast ultrasound – this type of scan may help doctors decide whether a lump or abnormality is a solid mass or a fluid-filled cyst.
- 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).
- 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.
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 therapist.
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
The main breast cancer treatment options may include:
- Radiation therapy
- Surgery
- Biological therapy (targeted drug therapy)
- Hormone therapy
- Chemotherapy.
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.
- 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.
