Can someone tell me how long will a patient live when the cancer has spread to the bone?

Depends on a some : Factors:1: it varies due to the type of the primary tumor, its location, where (besides the bone) has it spread to, eg, lungs or brain; how aggressive chemo/radiation therapy is given to him, his general condition, any other medical conditions he has; how he tolerates them? A cure is out of question, but with some cancers he may live a long time. Discuss it with your oncologist for a better idea.