question: Hi doctor, Before two years, my father was diagnosed with prostate cancer and has been undergoing treatment using Eligard and Xgeva. Early this year, he got diagnosed with vallecula carcinoma and for which he underwent chemo (Erbitux) six sittings and radiation therapy for 27 days. While vallecula seems to have subsided, he is now detected with tumor in some of the lymph nodes and for which operation has been recommended by the doctor. Also, as observed in PET scan cancer seems to be spreading to other parts as there are some areas highlighted in the lower part of the lungs. Doctor has not given clear guidance about that. We have been exploring the other options to retard spread of his cancer. We need your guidance on therapies that can be considered to extend his healthy life span. He is 73 years old. Wanted to check around immunotherapy for treatment and its availability. Thank you.