Father got diagnosed with stage 2b bone cancer. doc said he cant tell if it spread how come? whats the survival rate. says the primary is in bone

Bone Cancer Spread: The metastasis (spread) of primary tumors is confirmed by x-ray, MRI, CT Scan, or biopsy. Unless there is a visible lump or skin lesion, we cannot tell if there are any other tumors. Stage 2 is relatively early, and therefore treatable. Survival rate depends on the type of tumor, not just the tissue where it is found, as well as the amount of metastasis.