Managing Bone Metastases and Pain

http://www.prostatecancerfoundation....Metastases.htm

excerpt
b. Treating Bone Metastases

There are a few different kinds of treatments for prostate cancer bone
metastases. Because they all work in different ways, your doctors might
choose to use more than one in your treatment regimen. That doesn’t mean
your metastases are harder to treat or that your prognosis is worse. All
it means is that your doctors want to be sure that they will be able to
help keep your bones as strong and healthy as possible.

Before beginning any treatment regimen for bone metastases, your doctors
will likely discuss with you the importance of maintaining a healthy diet
and lifestyle. They will want to ensure that you’re taking in adequate
amounts of calcium and vitamin D, and that you’re exercising regularly.
Even though none of these are treatments for bone metastases, they will
all help you maintain strong bones and help to minimize bone loss and
osteoporosis, which can make treating your bone metastases more
challenging.

Men who experience pain from a bone metastasis will often be treated with
radiation targeted directly to the metastasis. This will kill the prostate
cancer cells that are sitting there and thereby relieve the pain. Note
that the goal of radiation therapy that is used to treat bone metastases
is completely unrelated to any radiation that you might or might not have
received earlier in your prostate cancer treatment. Regardless of whether
you had surgery, radiation, chemotherapy, or any other type of treatment
up until now for your prostate cancer, radiation to the bones can be used
to relieve the pain from bone metastases.

External beam radiation therapy uses x-rays to kill the cancer cells
sitting in your bones. This type of treatment, sometimes referred to as
spot radiation, is mapped out and planned very precisely by the radiation
oncologist to ensure that the x-rays are targeting the metastasis and are
not causing damage to the surrounding bone and muscle tissue. A procedure
known as hemi-body radiation, which is used less frequently, targets much
larger areas of the lower half of the body, which is where prostate cancer
bone metastases more typically grow.

A somewhat different approach uses radiopharmaceuticals to target the bone
metastases. These radioactive drugs, either samarium (Quadramet) or
strontium (Metastron), are injected into your body through a vein and
settle in the bone metastases, at which point they release radiation to
the local area and kill the cancer cells. Researchers have shown that
strontium can be very effective at relieving pain when used immediately
after the chemotherapy drug doxorubicin (Adriamycin), so your doctors
might decide to combine the two approaches in an attempt to give you the
most relief possible.

External beam radiation therapy and radiopharmaceuticals are known as
directed palliative treatments, meaning that they are used to relieve pain
in a specific area of the body. Drugs known as bisphosphonates are
systemic therapies that have been shown to relieve pain throughout the
body and to slow the onset of complications from bone metastases in men
with prostate cancer.

Under normal circumstances, bone cells are destroyed and created at a
constant rate. Increasing the activity of osteoblasts, cells that form new
bone cells, ultimately results in an overgrowth of bone tissue; increasing
the activity of osteoclasts, cells that destroy bone cells, ultimately
results in porous, brittle bone tissue. In men with prostate cancer bone
metastases, both of these processes occur at faster than normal rates,
leading to both an overgrowth of bone tissue and weakened and brittle
bones. The combination of these two processes makes the bones unstable,
and therefore prone to fracture.