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Cancer is cells growing out of control
There are many types of cancer. As with all cancers, affected cells
in the body change and grow out of control.
- Usually, the multiplying cancer cells form a lump called a tumor.
- Not all tumors are cancerous. Tumors that are not cancerous are
called benign tumors. Cells from benign tumors do not spread to other
parts of the body.
- Cancerous tumors are called malignant tumors. Sometimes malignant
tumor cells can break away from the original, primary tumor and travel
through the bloodstream or lymphatic system to other parts of the
body. This process is called metastasis (pronounced meh-tas-tuh-sis)
- Cancer is usually named after the part of the body where it first
develops — the primary site. Breast cancer begins in the breast
tissue. If it spreads to the lungs, for example, it is still
considered breast cancer, not lung cancer.
Cancer occurs when cells in a part of the body begin to grow out of
control. Normal cells divide and grow in an orderly fashion, but cancer
cells do not. They continue to grow and crowd out normal cells. Although
there are many kinds of cancer, they all have in common this
out-of-control growth of cells.
Different kinds of cancer can behave very differently. For example, lung
cancer and breast cancer are very different diseases. They grow at
different rates and respond to different treatments. That’s why people
with cancer need treatment that is aimed at their kind of cancer.
Sometimes cancer cells break away from a tumor and spread to other parts
of the body through the blood or lymph system. They can settle in new
places and form new tumors. When this happens, it is called
metastasis ( Cancer that has
spread in this way is called metastatic cancer.
Even when cancer has spread to a new place in the body, it is still
named after the part of the body where it started. For example, if
prostate cancer spreads to the bones, it is still called prostate
cancer. If breast cancer spreads to the lungs, it is still breast
cancer. When cancer comes back in a person who appeared to be free of
the disease after treatment, it is called a
recurrence.
Defining recurrence
Recurrence is the term used to describe the return of cancer
following primary treatment, either at the same site as the original
tumor or somewhere else in the body. Breast cancer can recur in the
following ways:
- Local recurrence occurs in the breast where the cancer
first started, or in the skin and underlying tissues where the breast
used to be. This type of recurrence can happen even if you've had a
mastectomy. In the soft tissues of the chest, cancer can grow from
breast cancer cells close to the skin or behind the breast area,
against the muscle of the chest wall. This type of local recurrence is
called a chest wall recurrence.
- Regional recurrence occurs in the lymph nodes near the
affected breast. These "regional" lymph nodes include nodes found
under the arm (axillary nodes) and those in the chest wall, such as
those under the breastbone or under the pectoral muscle at the front
of the chest. With regional recurrence, the cancer grows from cells
that were present but undetectable at the time of the original
surgery, or from cells that recurred in the breast and then later
spread to lymph nodes.
- Metastatic recurrence occurs in other parts of the body,
such as lymph nodes at the base of the neck, or in the lung, liver,
bone, or brain.
| What Is
Breast Cancer? |
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Breast cancer is a malignant (cancerous)
tumor that starts from cells of the breast. The disease occurs
mostly in women, but men can get breast cancer as well. The
information here refers only to breast cancer in women. There is
separate information about
breast cancer in men.
A woman’s breast is made up of glands that make breast milk
(lobules), ducts (small tubes that connect lobules to the nipple),
fatty and connective tissue, blood vessels, and lymph (pronounced
limf) vessels. Most breast cancers begin in the ducts (ductal
carcinoma), some begin in the lobules (lobular carcinoma),
and the rest in other tissues.
Lymph vessels are like veins, except that they carry lymph fluid
instead of blood. Lymph is a clear fluid that contains immune system
cells and waste products. Lymph vessels lead to small, bean-shaped
collections of tissue called lymph nodes. Most lymph vessels of the
breast lead to lymph nodes under the arm. These are called axillary
(AX-uh-lair-ee) nodes.
If breast cancer cells reach the underarm lymph nodes and
continue to grow, they cause the nodes to swell. Once cancer cells
have reached these nodes they are more likely to spread to other
organs of the body as well.
Benign Breast Lumps
Most breast lumps are benign; that is, they are not cancer.
Benign breast tumors are abnormal growths, but they do not spread
outside of the breast and they are not life threatening. But some
benign breast lumps can increase a woman’s risk of getting breast
cancer.
Most lumps turn out to be caused by fibrocystic (fi-bro-SIS-tik)
changes. Cysts are fluid-filled sacs. Fibrosis is the formation of
scar-like tissue. Such changes can cause breast swelling and pain.
The breasts may feel lumpy, and sometimes there is a clear or
slightly cloudy nipple discharge.
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Parts of the breast
The breast, also called a mammary gland, is made up of lobules,
ducts, fatty tissue, blood vessels, and lymph vessels.
- Lobules are glands in the breast that produce milk.
- Ducts are tubes that link the lobules to the nipple.
- Fatty tissue surrounds the lobules and ducts.
- Blood vessels are tubes that circulate blood throughout the body.
Blood vessels include arteries, arterioles, capillaries, venules, and
veins.
- Lymph vessels carry lymph to lymph nodes in the underarm (axilla),
above the collarbone, and in the chest. Lymph is the clear fluid that
carries infection-fighting cells through the body.
 
Doctors use the term "stage" to refer to the extent of cancer within
the body. You may be given tests to find out whether cancer has spread.
Knowing the stage of your cancer can help you and your doctor determine
your best treatment plan.
Early breast cancer
The term "early breast cancer" refers to stages of breast cancer
labeled 0, I, II, and IIIA.
- In stage 0, cancer cells are present in either the lining
of a breast lobule or a duct, but they have not spread to the
surrounding fatty tissue. This stage is also called ductal carcinoma
in situ, or DCIS. Ductal carcinoma in situ (DCIS): This is the
most common type of noninvasive breast cancer. DCIS means that the
cancer is confined to the ducts. It has not spread through the walls
of the ducts into the fatty tissue of the breast. Nearly all women
with cancer at this stage can be cured. The best way to find DCIS
early is with a mammogram.
- In stage I, cancer has spread from the lobules or ducts to
nearby tissue in the breast. At this stage and beyond, breast cancer
is considered to be invasive. The tumor is 2 cm or less in diameter
(approximately 1 inch or less); cancer has not spread to the lymph
nodes. Infiltrating (invasive) ductal carcinoma (IDC): This is
the most common breast cancer. It starts in a milk passage or duct,
breaks through the wall of the duct, and invades the fatty tissue of
the breast. From there it can spread to other parts of the body. IDC
is the most common type of breast cancer. It accounts for about 80% of
invasive breast cancers.
- In stage II, the tumor can range from 2 cm to less than 5
cm in diameter (approximately 1 to 2 inches); sometimes cancer may
have spread to the lymph nodes.
- In stage IIIA, the tumor is 5 cm or greater in diameter
(approximately 2 inches or greater); or the tumor may be of any size
where cancer cells have grown extensively into axillary (underarm)
lymph nodes.
Advanced breast cancer
The term "advanced breast cancer" includes breast cancer stages IIIB
and IV.
- In stage IIIB, known as locally advanced cancer; tumor may
be of any size, but has spread into the skin of the breast or tissues
of the chest wall.
- In stage IV, known as metastatic; cancer has spread from
the breast to other parts of the body, such as bone, liver, lung, or
brain.
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