Cancer
in the Bones
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Cancer growing in bone
can cause tremendous pain and disability. As the
tumor cells grow, they make the bone porous and
weak. Bones can break with the slightest action—such
as stepping off a curb or rolling over in bed.
"Bone cancer"
as it is often called, can be caused either by
tumors which form directly from bone cells, or
tumors from other body sites can spread to the
bones. The first type of "bone cancer"
is very rare and is called a sarcoma. Sarcomas
usually occur on the arms or legs. In the past,
amputation was the only treatment. However, that
is no longer the case. Successful treatment can
often be achieved using a combination of
chemotherapy and radiation therapy to shrink the
tumor. If this is successful, an operation to
remove the tumor can often be done without
sacrificing the limb. It requires a team approach,
and we are fortunate to have such |
| a team of doctors
at our cancer centre in Tampa with experience
in treating these tumors. |
The second type
of "bone cancer" is called metastasis.
This is a much different kind of problem as several
bones are usually affected at the same time. Tumor cells
which have traveled to the bone through the bloodstream
cannot be cured by surgery or spot radiation. Depending
upon the type of tumor, chemotherapy, hormone therapy,
bone hardening chemicals (bisphosphonates), or intravenous
radioactive particles (Quadramet®)
are often used. For specific painful spots, or for weight
bearing bones which might break, radiation therapy is
very effective. Spot radiation usually relieves pain
within two weeks. And, by killing the cancer in that
spot, the bone can heal and become solid again. This
is an important part of maintaining a good quality of
life for many patients with cancer.
In addition to the more conventional
treatments described on these pages, we occasionally
recommend highly individualized approaches. For instance,
in some circumstances, it is possible to run chemotherapy
directly into the blood supply to the tumor, instead
of exposing the entire body. We have a cell culture
laboratory where anti-tumor vaccines and tumor-infiltrating
lymphocytes can be grown. Our interventional radiologists
are skilled at tumor embolization which plugs the blood
supply to tumors. Vertebroplasty is a procedure to inject
plastic into damaged spinal bones. This stabilizes them
and relieves pain.
One of the devastating complications
of bone cancer occurs when tumors grow within the spine.
This weakens the bones in the back and patients suffer
painful compression fractures. The picture to the left
is a scan through the back showing the normal back bones.
This picture shows
a collapsed bone
in the back. Such damaged bones
may
be temporarily repaired with vertebroplasty.
Each is approximately square, and
dark in color. The broken bone
appears white, and is triangular in shape. In addition
to pain, displaced fragments of bone and tumor can press
on the spinal cord. The spinal cord is the bundle of
nerves connecting our brains with our arms and legs.
If it is damaged, patients can become paralyzed.
Management of Metastases
When cancer
enters the bloodstream, malignant cells are carried
throughout the body. Frequently, they lodge in tissues
such as the lungs, liver, bone and brain, and begin
to grow there. This process is called "Metastasis."
The formation of metastases the one of the major
obstacles to cure of cancer patients. In order for cancer
cells to grow into masses, they must have oxygen and
nutrition. Cancer cells produce chemicals which cause
new blood vessels to form, feeding the growing tumor.
This process is called "angiogenesis."
Treatment of metastases is varied. It depends upon the
type of cancer, the site of the metastasis, the number
of metastases, and general health of the patient.
Usually, treatment of metastases requires the use of
medicines which can circulate through the bloodstream
and fight cancer cells wherever they may be. This could
be in the form of chemotherapy, hormones, anti-tumor
antibodies, or chemicals which interfere with angiogenesis
(such as thalidomide). The type of medicine used depends
upon the type of cancer under treatment. Unfortunately,
these chemicals also expose normal cells and can cause
systemic side effects. When cancers spread, they tend to behave as they did
when they originally formed. That is, breast cancer
which has spread to the bone does become "bone
cancer". It remains breast cancer but in the bones.
Thus, treatments which are usually effective against
cancer in the breast are often effective against breast
cancer in the bones. When talking with your doctor, be sure to ask questions
such as these: |
- Systemic chemotherapy
- Hormonal therapy for hormonally
sensitive tumors such as breast, prostate and uterine
cancers
- External beam radiation therapy—especially
for tumors which are bleeding or causing blockages
of the airway
- Surgery for certain types of tumors
such as certain sarcomas, and for patients who have
a limited number of metastases
Investigational agents such as new
chemotherapy drugs, angiogenesis inhibitors, gene therapy,
tumor vaccines are often considered when patients develop
metastases after other treatments have been tried. Often,
this requires patients to be treated as part of scientific
studies that pool their data with other patients to
determine how successful the new treatment is. Because
these are largely untested treatments, the benefits
may be unknown. However, all modern effective treatments
have come about through this process. In addition, investigational
treatments are frequently provided for free to patients
who agree to be on such studies. As with all treatments,
discuss risk and benefits with your physician.
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