|
The term, metastatic, describes a
cancer that has spread to distant organs from the original tumor site. Metastatic breast
cancer is the most advanced stage (stage IV) of breast cancer.
Cancer cells have spread past the breast and axillary (underarm) lymph nodes to other
areas of the body where they continue to grow and multiply. Breast cancer has the
potential to spread to almost any region of the body. The most common region breast cancer
spreads to is the bone, followed by the lung and liver. Treatment of metastatic breast cancer
generally focuses on relieving symptoms and extending a woman’s lifetime.
Main Menu:
Diagnosis
Breast cancer often begins in the
breast ducts as ductal carcinoma in situ (DCIS). Once out of the breast, cancer often
spreads first to the axillary (underarm) lymph nodes. One or more of the lymph nodes are
usually removed during breast surgery to determine whether the nodes are involved. (See
the axillary node dissection and sentinel node biopsy sections for more information on how
lymph nodes are removed). In some cases, breast cancer may spread to other regions of the
body without involving the axillary lymph nodes. If the cancerous tumor is located in the
medial portion of the breast (near the nipple), it may spread to the internal mammary
nodes which are located between the ribs and beneath the sternum. In some cases, cancer
may spread through the bloodstream without being detected in the lymphatic system.
In 10% of breast cancer diagnoses, the
cancer has already spread to distant organs in the body. A primary diagnosis of Stage IV
breast cancer may indicate a rapid progression of the disease or that the cancer was
present but not detected in the breast for some time. To help detect breast cancer in its
earlier stages when it is most curable, women should follow the guidelines for early detection established by the American
Cancer Society which include monthly breast self-examinations,
annual clinical breast exams, and annual mammography (the latter beginning at age 40).
Metastatic breast cancer may also occur
from a recurrence (return) of breast cancer after initial
treatment. There are three types of breast cancer recurrences: local, regional, and
distant. Local and regional recurrences are usually less serious than distant recurrences
and may be detected by mammogram or seen as abnormalities with
breast imaging exams (such as ultrasound or T-scan). Once a local or regional recurrence is detected,
physicians will order a variety of other tests to determine whether the cancer has
metastasized (spread) to distant organs. These tests include:
Blood tests (also called tumor marker tests) measure non-specific markers
found in the blood that can be followed over time. Two such markers for
breast cancer are CEA (carcinoembryonic antigen) and CA 15-3. These markers
tend to be elevated in women with metastatic breast cancer. However, because
the tests are not very sensitive, they are not usually very useful for
patients with early-stage breast cancers.
CEA, or carcinoembryonic antigen, is a "marker" for breast or other cancer
recurrence. It is a special protein that is actually produced in embryonic
cells and regenerating cells, as well as cancer cells. This protein is found
on the surface of cells and can be measured in blood tests, as cells shed
these proteins. In the past, these markers have been used to monitor a
patient after treatment for cancer; a rise in the level would indicate the
need to search more fully for a recurrence of cancer. For example, it may
trigger a patient's doctor to order a battery of tests, such as chest
x-rays, CT scans and so on, to look for recurrent or metastatic tumor in
organs such as the lung or liver.
However, the CEA level can also be elevated in a number of benign
(non-cancerous) conditions. Some of these include stomach ulcers, colon
polyps, cigarette smoking, among other causes. If an oncologist has not
found any reason to suspect cancer recurrence, then patients are usually
correct to follow his or her advice. Some oncologists do not use these
markers to follow patients anymore as it sometimes creates unnecessary
anxiety.
CA 15-3 is another serum cancer antigen that is used in the management of
some patients with breast cancer. It is most effective at monitoring
metastatic breast cancer, but has not had high success at detecting early
stage breast cancers. While CA 15-3 is not typically used alone in
evaluating metastatic breast cancer patients, it can provide useful
additional information about whether a patient is responding to treatment.
If the cancer has not spread to other
organs, treatment of local or regional recurrences often depends on how the initial
treatment was performed. If lumpectomy was performed,
recurrent breast cancer will usually be treated with mastectomy.
If the cancer has spread to other areas of the body, the situation is more serious.
Symptoms of metastatic breast cancer
may include:
- Bone pain (possible indication of bone
metastases)
- Shortness of breath (possible indication
of lung metastases)
- Lack of appetite (possible indication of
liver metastases)
- Weight loss (possible indication of
liver metastases)
- Neurological pain or weakness, headaches
(possible indications of neurological metastases)
These symptoms are sometimes but not
always associated with metastatic breast cancer, and having one or more of these symptoms
does not necessarily mean a woman has metastatic breast cancer. Most women whose breast
cancer has metastasized do not show symptoms until the disease is extensive.
Where Can
Breast Cancer Spread?
Breast cancer can spread to almost any
area of the body. The most common regions that breast cancer may spread to in order of
frequency are:
Bone: Approximately 25% of breast cancers
spread first to the bone. The bones of the spine, ribs, pelvis, skull, and long bones of
the arms and legs are most often affected. There are two types of bone metastases:
osteolytic and osteoblastic. With osteolytic metastases, the cancer eats away at the bone,
forming holes. This most often occurs in the legs, hip, or pelvis. Osteoblastic metastases
actually increase bone mineral density
but also cause bones to fracture easily. Both types of bone metastases cause pain.
Researchers are investigating whether a class of drugs called bisphosphonates may be helpful in treating
effects of bone metastases. Bone metastases can cause pain, decreased activity, and potentially severe
problems such as fractures. Other complications that can arise from bone metastases include the surgical
treatment for fractures, hypercalcemia (abnormally high levels of calcium), and spinal cord compression
(vertebral damage due to pressure on the spinal cord).
Currently, Aredia is the only FDA-approved
bisphosphonate to treat breast cancer patients with bone metastases. Aredia is administered intravenously
(through a vein) along with other cancer treatments, such as chemotherapy. Clinical studies
have shown that breast cancer patients with bone metastases who are given Aredia tend to experience a delay in
or reduction of bone pain, fractures, and other bone complications compared to patients who do not
receive Aredia. Possible side effects of Aredia include fever, fatigue, nausea and vomiting, initial bone
pain, lack of appetite, and anemia (decrease in red blood cells).
Other bisphosphonates have also shown promise in alleviating symptoms of bone metastases. In a recent study,
an experimental bisphosphonate called ibandronate stopped the progression of bone metastases in mice and
halted the formation of new metastases. Other bisphosphonates under investigation for treating bone metastases include:
- Didronel (generic name, etidronate)
- Bonefos, Clostoban, Loron, Ostac (generic name, clodronate)
- Skelid (generic name, tiludronate)
- Fosamax (generic name, alendronate)
- Zometa (generic name, zoledronate)
At this time, most physicians do not see sufficient evidence to recommend bisphosphonates for breast cancer patients
who do not already have bone metastases.
Lung:Between 60% and 70% of women who die
from breast cancer have eventually had it spread to their lungs. In 21% of cases, the lung
is the only site of metastatis (spread). The most common signs of lung metastases are:
shortness of breath and dry cough. In some cases, women will not experience any symptoms;
cancer will only be detected by chest X-ray or CT scan. In rare cases, part of the lung may be surgically
removed if the cancer is confined to one area. However, in most cases, the cancer has
spread itself throughout the lung and is more effectively treated by chemotherapy
or other anti-cancer drugs.
Liver:The liver is the third most common site
for breast cancer to spread to after bone and lung. Two-thirds of women with metastatic
breast cancer eventually have it spread to the liver. Symptoms of liver metastases are
subtle at first but become increasing intense over time. Weight loss, loss of appetite,
fever, and gastrointestinal disorders may indicate liver metastases. Liver blood tests may
first detect cancer in the liver. However, a liver biopsy is
necessary to distinguish between cancerous tumors and other abnormalities.
Breast cancer may also spread to other
regions of the body. Though these sites are less common, breast cancer may infect the bone
marrow, brain, ovaries, spinal cord, eye, and other areas.
CONTINUED
1 | 2 | Next >
Return to Breast Health Main Menu |
