The breast is made up of glands called lobules that can make milk and thin tubes called ducts that carry the milk from the lobules to the nipple. Breast tissue also contains fat and connective tissue, lymph nodes, and blood vessels.
The most common type of breast cancer is ductal carcinoma, which begins in the cells of the ducts. Breast cancer can also begin in the cells of the lobules and in other tissues in the breast. Invasive breast cancer is breast cancer that has spread from where it began in the ducts or lobules to surrounding tissue.
In the U.S., breast cancer is the second most common cancer in women after skin cancer. It can occur in both men and women, but it is very rare in men. Each year there are about 2,300 new cases of breast cancer in men and about 230,000 new cases in women.
Breast cancer is a kind of cancer that develops from breast cells. 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 aslobular 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.
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 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.
- Breast cancer is a disease in which malignant (cancer) cells form in the tissues of the breast.
- Having a family history of breast cancer and other factors increase the risk of breast cancer.
- Breast cancer is sometimes caused by inherited gene mutations (changes).
- Decreasing the length of time a woman’s breast tissue is exposed to estrogen decreases the risk of breast cancer.
- Signs of breast cancer include a lump or change in the breast.
- Tests that examine the breasts are used to detect (find) and diagnose breast cancer.
- If cancer is found, tests are done to study the cancer cells.
- Certain factors affect prognosis (chance of recovery) and treatment options.
SYMPTOMS OF BREAST CANCER
Breast cancer can have a number of symptoms, but the first noticeable symptom is usually a lump or area of thickened breast tissue.
Most breast lumps aren’t cancerous, but it’s always best to have them checked by your doctor. You should also see your GP if you notice any of the following:
- a change in the size or shape of one or both breasts
- discharge from either of your nipples (which may be streaked with blood)
- a lump or swelling in either of your armpits
- dimpling on the skin of your breasts
- a rash on or around your nipple
- a change in the appearance of your nipple, such as becoming sunken into your breast
- Breast pain isn’t usually a symptom of breast cancer.
After examining your breasts, your GP may refer you to a specialist breast cancer clinic for further tests. This might include a mammography (breast screening) or a biopsy.
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 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.
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.”
Breast ultrasound –
This type of scan may help doctors decide whether a lump or abnormality is a solid mass or a fluid-filled cyst.
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.
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.
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.
TYPES OF BREAST CANCER
There are several different types of breast cancer, which can develop in different parts of the breast. Breast cancer is often divided into non-invasive and invasive types.
NON-INVASIVE BREAST CANCER
Non-invasive breast cancer is also known as cancer or carcinoma in situ. This cancer is found in the ducts of the breast and hasn’t developed the ability to spread outside the breast.
This form of cancer rarely shows as a lump in the breast that can be felt, and is usually found on a mammogram (see below).The most common type of non-invasive cancer is ductal carcinoma in situ (DCIS).
INVASIVE BREAST CANCER
Invasive cancer has the ability to spread outside the breast, although this doesn’t necessarily mean it has spread.
The most common form of breast cancer is invasive ductal breast cancer, which develops in the cells that line the breast ducts. Invasive ductal breast cancer accounts for about 80% of all breast cancer cases and is sometimes called “no special type”.
OTHER TYPES OF BREAST CANCER
Other less common types of breast cancer include invasive lobular breast cancer, which develops in the cells that line the milk-producing lobules, inflammatory breast cancer and Paget’s disease of the breast.
It’s possible for breast cancer to spread to other parts of the body, usually through the lymph nodes (small glands that filter bacteria from the body) or the bloodstream. If this happens, it’s known as “secondary” or “metastatic” breast cancer.
TREATMENT OF BREAST CANCER
In recent years, there’s been an explosion of life-saving treatment advances against breast cancer, bringing new hope and excitement. Instead of only one or two options, today there’s an overwhelming menu of treatment choices that fight the complex mix of cells in each individual cancer. The decisions — surgery, then perhaps radiation, hormonal (anti-estrogen) therapy, and/or chemotherapy — can feel overwhelming.
Planning Your Treatment
What types of treatment are available, the most likely sequence of treatments, treatment options by cancer stage, and fitting treatment into your schedule.
Getting a Second Opinion
Reasons for getting a second opinion about your treatment plan, how to go about getting one, and what to do once you’ve got it.
Breast-conserving surgery (lumpectomy), mastectomy, and lymph node dissection, and what to expect from each. Also included: Prophylactic surgery and breast reconstruction.
How chemotherapy works, who should get it, different types and combinations, and side effects and how to manage them.
How radiation therapy works, who it’s for, advantages, side effects, and what to expect when you get it.
The link between hormones and breast cancer and how different groups of drugs — including ERDs, SERMs, and aromatase inhibitors — can affect that link. Also covered: Side effects of hormonal therapies.
How they work, who should get them, how they’re given, side effects, and major studies.
Complementary & Holistic Medicine
How complementary medicine techniques such as acupuncture, meditation, and yoga could be a helpful addition to your regular medical treatment. Includes research on complementary techniques and ways to find qualified practitioners.
Drugs for Treatment and Risk Reduction
A reference list of drugs used to treat and reduce the risk of breast cancer, including how they work, to whom they are typically given, and side effects.
Treatments for Pain
Ways to treat cancer- and treatment-related pain, including types of medications and tips on talking to your doctors about pain.
Treatment Side Effects
A reference list of side effects and ways to manage them.
All about lymphedema, including who is at risk, what to watch out for, how to reduce risk of lymphedema flare-ups, and how to find a lymphedema therapist.
What clinical trials are and how they work, why they’re important, and how to find trials that may be appropriate for you.