71 yrs old male c/o severe back pain for months following a di | sᴘᴏᴛ ᴅɪᴀɢɴᴏsɪs

71 yrs old male c/o severe back pain for months following a diagnosis of prostate cancer patients received palliative radiotherapy and ibuprofen for pain with no improvement Neurological Ex where normal, best next step in pain management of this patient :