<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hello, My dad 69 yrs old was recently diagnosed with Prostate cancer -- stage 4. His PSA level is 110 but bone scan came back negative. His biopsy reflected a Gleason score of 347. Hes always been very healthy and also has no other urinary tract problems commonly associated with prostate cancer. However he has had a severe lower back pain these past three months - this was also aggravated by a recent fall. Hes now on complete bed rest because hes unable to walk. Is this indeed stage 4 of the disease? But his bone scan shows up negative. What are his chances of survival? Please advise. Thanks.  <response>: Hi, dairy have gone through your question. I can understand your concern. He may have metastatic carcinoma in spine. It causes back pain. He has Gleason score 7, so it suggests good prognosis. But he has stage 4 disease do difficult to treat. Chemotherapy and radiotherapy is the treatment of choice. Despite treatment life expectancy is not good. Consult your doctor and plan accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using Chat Doctor. Wish you a very good health. 