with regards to your mother, the changes in the X rays, could be due to 2 scenarios.
1. if your mother is above 45 years (which is my guess), these changes could be due to osteoporosis
2. In case of advanced cancer, the release of cytokines by the body, as a reaction to cancer, could cause degenerative changes in the bones.
the treatment in both cases - is Vitamin D & calcium supplements
(To strengthen the bones) and supportive medications like alendronate
which can prevent bone loss and deterioration.
In cases where the cancer directly involves the bones (in form of metastases) there would be seen as separate lesions and not as degenerative changes.
You can consult the treating oncologist
, and he will do the needful.
Hope this helps.
Dr Deepak Anvekar.