I am Bidesh Bose from west Bengal. My father attack by oral cancer on buccal mucosa from 8 months, 1st time we take treatment from mumbai cancer hospital, then they give the procedure for treatment and they told that there have no scope for surgery, patient need to take chamotharapy and radiation, then we return at west Bengal, then we meet Dr. Asish Mukherjee and we submit the mumbai hospital s documents, then he give 6 round chemotherapy and told to us after 15 days please take a scan report and we do this and submit scan report to Dr Asish Mukherjee and he told that cancer is improved like 30%, then he suggest to us please go to kolkata medical college and take readiation, then do that, My father take 33 pcs radiation, after the treatment radiologist check to patient and told that I think the tumor is totally removed but it is 4th stage cancer but I will be sure about that after 21 days, but it is not curable totally but after treatment the life return to better life, please bring out the patient after 21 days for checkup. Radiation therapy completed 18 days ago, but my father fills too much pain and he take painkiller on the meantime, then the pain is relief but again pain is return after few hours, please tell me the reason for pain and how much days radiation is working to die the cancer cell ?