Radiation and bone mets

I was diagnosed in 1996, at the age of 32, with breast cancer.  I've had metastatic disease for the past 5 years in my bones only.  After going through all the standard treatments (hormone therapy, bisphosphonates, radiation, and chemo (Xeloda), the disease has spread to nearly every bone in my body.  I've had multiple fractures to my femur, humerus, and ribs.  Now, it has spread to my spine, and my quality of life is really going downhill.  My questions are:
1) Why am I getting such severe muscle spasms in my back?  Are they related to the mets in my spine, and would radiation do anything to help reduce their occurrence?  I haven't experienced muscle spasms in the other areas of my body.
2) Is it worthwhile to have more radiation if it is strictly palliative?  I've already had radiation to 8 areas and I'm worried about the side effects.  Unlike most people, I haven't gotten much pain relief from past radiation treatments.  Will radiation help prevent another fracture?
3) Do you think I might benefit from Strontium 89 or one of the other radio-isotopes?  The majority of my lesions are blastic. I am in good general health.
Sorry for so many questions, but I am experiencing so much pain, and other than taking narcotics, nothing seems to help.  Thank you so much for any advice you can give me.

[CCF-RN,MSN-JS]

Dear srazz: The goals of treatment of metastatic breast cancer are control of the disease and symptoms.  With any type of treatment being considered this goal of treatment needs to be kept in mind.  The risks and benefits are considered: control of pain, prevention of fractures are benefits that are meant to improve quality of life.  The role of radiation is to treat an area of disease, with the hoped for result of pain relief and prevention of fractures to that site.  The amount of radiation to a certain area is calculated and only a certain amount can be safely given to a specific location.  Strontium 89 is a radioisotope the approved use is for the relief of bone pain in patients with painful bone metastases, it is given as an intravenous injection and has an effect on bone metastasis throughout the body.  
One of the risks that would be considered in terms of the radiation (localized as well as the Strontium-89) is the amount of radiation to the bone marrow.  The bone marrow is where our blood cells are produced.  If too much radiation is given to the bone marrow there may be a decreased production of white blood cells (help to fight infection), red blood cells (help to carry oxygen through the body) and platelets (help to clot the blood, prevent bleeding).   Evaluation of the risks of treatment will need to be considered carefully versus the benefits of this treatment for your individual situation and you'll want to discuss this with your oncologist.  Other treatments that may help to palliate bone pain include intravenous bisphosphonates such as zoledronate (Zometa) or pamidronate (Aridea) or even additional chemotherapy or hormonal therapy treatments that have not yet been tried.  These issues should be further discussed with an oncologist.
Regarding the muscle spasms, they could be related to the pain in the spine - for example the muscles may be tensing because of the pain and then spasming.  What methods are used for pain control are based on a complete evaluation of the problem.  Discussion of location, characteristics of the pain, things that help to relieve, or what makes the pain worse are all pieces of information that need to be assessed, as well as physical examination and information from testing,  in order to recommend a plan to optimize pain control.

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