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What is breast cancer?
Cells in the body normally divide (reproduce) only
when new cells are needed. Sometimes, cells in a part of the body grow and
divide out of control, which creates a mass of tissue called a tumor. If the
cells that are growing out of control are normal cells, the tumor is called
benign (not cancerous). If, however, the cells that are growing out of control
are abnormal and don't function like the body's normal cells, the tumor is
called malignant (cancerous).
Cancers are named after the part of the body from which they
originate. Breast cancer originates in the breast tissue. Like other cancers,
breast cancer can invade and grow into the tissue surrounding the breast. It can
also travel to other parts of the body and form new tumors, a process called
metastasis.
What causes breast cancer?
We do not know what causes breast cancer, although we
do know that certain risk factors may put you at higher risk of developing it. A
woman's age, genetic factors, personal health history, and diet all
contribute to breast cancer risk.
Who gets breast cancer?
Breast cancer is the most common cancer among women
other than skin cancer.
In the US, breast cancer is the second-leading cause of cancer death in
women after lung cancer, and it's the leading cause of cancer death among women
ages 35 to 54. Only 5 to 10% of breast cancers occur in women with a clearly
defined genetic predisposition for the disease. The majority of breast cancer
cases are "sporadic," meaning there is no direct family history of the
disease. Increasing age is another risk factor for developing breast cancer.
What are the warning signs of breast cancer?
- A lump or thickening in or near the breast or in the
underarm that persists through the menstrual cycle
- A mass or lump, which may feel as small as a pea
- A change in the size, shape, or contour of the breast
- A blood-stained or clear fluid discharge from the
nipple
- A change in the look or feel of the skin on the
breast or nipple (dimpled, puckered, scaly, or inflamed)
- Redness of the skin on the breast or nipple
- An area that is distinctly different from any other
area on either breast
- A marble-like hardened area under the skin
These changes may be found when performing monthly breast
self-exams. By performing breast self-exams, you can become familiar with the
normal monthly changes in your breasts.
Breast self-examination should be performed at the same time
each month, three to five days after your menstrual period ends. If you have
stopped menstruating, perform the exam on the same day of each month.
What are the types of breast cancer?
The most common types of breast cancer are:
- Infiltrating (invasive) ductal carcinoma. This cancer
starts in the milk ducts of the breast. It then breaks through the wall of
the duct and invades the fatty tissue of the breast. This is the most common
form of breast cancer, accounting for 80% of cases.
- Ductal carcinoma in situ is ductal carcinoma in its
earliest stage (stage 0). In situ refers to the fact that the cancer hasn't
spread beyond its point of origin. In this case, the disease is confined to
the milk ducts and has not invaded nearby breast tissue. If untreated,
ductal carcinoma in situ may become invasive cancer. It is almost always
curable.
- Infiltrating (invasive) lobular carcinoma. This cancer
begins in the lobules of the breast where breast milk is produced, but has
spread to surrounding tissues or the rest of the body. It accounts for
10 to 15% of breast cancers.
- Lobular carcinoma in situ is a marker for cancer that
is only in the lobules of the breast. It isn't a true cancer, but serves as
a marker for the increased risk of developing breast cancer later, possibly
in both or either breasts. Thus, it is important for women with lobular
carcinoma in situ to have regular clinical breast exams and mammograms.
Cancers can also form in other parts of the breast but are
more rare.
What are the stages of breast cancer?
Early stage, or stage 0, breast cancer is when the disease is
localized to the breast and lymph nodes (carcinoma in situ).
Stage I breast cancer: The cancer is
smaller than 1-inch across and hasn't spread anywhere.
Stage II
breast cancer is one of the
following:
- The tumor is less than an inch across but has spread to the underarm
lymph nodes (IIA); or
- The tumor is between 1 and 2 inches (with or without spread to
the lymph nodes); or
- The tumor is larger than 2 inches and has not spread to the
lymph nodes under the arm (both IIB).
Advanced
breast cancer (metastatic)
results after cancer cells spread to the lymph nodes and to other parts of the
body.
Stage III breast cancer is also
called "locally advanced breast cancer." The tumor is larger than 2 inches and has
spread to the lymph nodes under the arm, or a tumor that is any size with
cancerous lymph nodes that adhere to one another or to surrounding tissue (IIIA).
Stage IIIB breast cancer is a tumor
of any size that has spread to the skin, chest wall, or internal mammary lymph
nodes (located beneath the breast and inside the chest).
Stage IV
breast cancer is defined as a tumor, regardless of size, that has spread to
areas away from the breast,
such as bones, lungs, or lymph nodes.
How is breast cancer diagnosed?
During your regular physical examination, your doctor will take
a thorough personal and family medical history. He or she will also perform
and/or order one or more of the following:
During the
breast exam, the doctor will carefully feel the lump and the tissue around it.
Breast cancer usually feels different (in size, texture, and movement)
than benign lumps.
Mammography:
An X-ray test of the
breast can give important information about a breast lump.
Digital mammography: A technique
in which an X-ray image of the breast is digitally recorded into a computer
rather than on a film. While study results
have not shown that digital images are more effective in finding cancer
than X-ray images, they may reduce your exposure to radiation.
Ultrasonography: This test uses
sound waves to detect the character of a breast lump -- whether it is a fluid-filled cyst (not cancerous) or a solid mass (which may or may not be cancerous).
This may be performed along with the mammogram.
Based on the results of these tests, your doctor may or may
not request a biopsy test to get a sample of the breast mass cells or tissue.
Biopsies are performed using surgery or needles.
After the sample is removed, it is sent to a lab for testing.
A pathologist -- a doctor who specializes in diagnosing abnormal tissue changes
-- views the sample under a microscope and looks for abnormal cell shapes or
growth patterns. When cancer is present, the pathologist can tell what kind of
cancer it is (ductal or lobular carcinoma) and whether it has spread beyond the
ducts or lobules (invasive).
Laboratory tests, such as hormone receptor tests (estrogen and
progesterone), can show whether hormones are helping the cancer grow. If the test
results show that they are (a positive test), the cancer is
likely to respond to hormonal treatment. This therapy deprives the cancer of the
estrogen hormone.
Breast cancer diagnosis and treatment are best accomplished by
a team of experts working together with the patient. Each patient needs to
evaluate the advantages and limitations of each type of treatment and work with
her team of physicians to develop the best approach.
Other diagnostic tests
Other methods being investigated include:
- Scintimammography: A technique in which radioactive
contrast agents are injected into a vein in the arm. An image of the breast
is taken with a special camera, which detects the radiation (gamma rays)
emitted by the dye. Tumor cells, which contain more blood vessels than
benign tissue, collect more of the dye and project a brighter image.
- Positron Emission Tomography (PET) scanning: A
technique that measures a signal from injected radioactive tracers that
migrate to the rapidly dividing cancer cells. The PET scanner picks up
the signal and creates an image.
- Magnetic Resonance Imaging (MRI): A test that produces
very clear pictures, or images, of the human body without the use of X-rays. MRI uses a large magnet, radio waves, and a computer to produce these images.
- Scientists are also exploring ways to detect breast
cancer or markers of cancer in the blood, urine, and in fluid taken from the
nipple.
How is breast cancer treated?
If the tests find cancer, you and your doctor will develop a
treatment plan to eradicate the breast cancer, to reduce the chance of cancer
returning in the breast, as well as to reduce the chance of the cancer traveling
to a location outside of the breast. Treatment generally follows within a few
weeks after the diagnosis.
The type of treatment recommended will depend on the size and
location of the tumor in the breast, the results of lab tests done on the cancer
cells, and the stage, or extent, of the disease. Your doctor will usually consider your
age and general health as well as your feelings about the treatment options.
Breast cancer treatments are local or systemic. Local
treatments are used to remove, destroy, or control the cancer cells in a specific
area, such as the breast. Surgery and radiation treatment are local treatments.
Systemic treatments are used to destroy or control cancer cells all over the
body. Chemotherapy and hormone therapy are systemic treatments. A patient may
have just one form of treatment or a combination, depending on her needs.
Surgery
Breast conservation surgery involves removing the cancerous
portion of the breast and an area of normal tissue surrounding the cancer, while
striving to preserve the normal appearance of the breast. This procedure has
often been called a lumpectomy, which is a partial mastectomy. Some of the lymph nodes
under the arm are also removed. Usually, six to eight weeks of radiation therapy
is then used to treat the remaining breast tissue. Most women who have a small,
early-stage tumor are excellent candidates for this approach.
Mastectomy (removal of the entire breast) is another option.
The mastectomy procedures performed today are not the same as the older, radical
mastectomies. Radical mastectomies were extensive procedures that involved
removing the breast tissue, skin, and chest-wall muscles. Today, mastectomy
procedures do not ordinarily remove muscles and, for many women, mastectomies
are accompanied by either immediate or delayed breast reconstruction.
What happens after treatment?
Following local breast cancer treatment, the treatment team
will determine the likelihood that the cancer will recur outside the breast.
This team usually includes a medical oncologist, a specialist trained in using
medicines to treat breast cancer. The medical oncologist, who works with the
surgeon, may advise the use of the drug tamoxifen or possibly chemotherapy. These
treatments are used in addition to, but not in place of, local breast cancer
treatment with surgery and/or radiation therapy.
Does a benign breast condition mean that I have a higher risk
of getting breast cancer?
Benign breast conditions rarely increase your risk of breast
cancer. Some women have biopsies that show a condition called hyperplasia
(excessive cell growth). This condition increases your risk only slightly.
When the biopsy shows hyperplasia and abnormal cells, which is a
condition called atypical hyperplasia, your risk of breast cancer increases
somewhat more. Atypical hyperplasia occurs in about 5 percent of benign breast
biopsies.
How can I protect myself from breast cancer?
Follow these three steps for early detection:
- Get a mammogram. The American Cancer Society recommends
having a baseline mammogram at age 35, and a screening mammogram every year
after age 40. Mammograms are an important part of your health history. If
you go to another healthcare provider, or move, take the film (mammogram)
with you.
- Examine your breasts each month after age 20. You will
become familiar with the contours and feel of your breasts and will be more
alert to changes.
- Have your breast examined by a healthcare provider at
least once every three years after age 20, and every year after age 40.
Clinical breast exams can detect lumps that may not be detected by
mammogram.
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