Ramamurthy,
I'm 2 years post all treament, but very new to this site, so I'll let others who have been here longer answer your questions. In the meantime, try reading others' posts and find out what you can, along with the search for specific questions. I found it helpful to see who's logged in, look at their profile, and then read some of their posts.
My first thought, though, is to tell you to seek a 3rd opinion. Hopefully 2 of the 3 doctors will agree. Are you being treated by a doctor who specializes in oral cancer? If not, you should find one for that 3rd opinion, and stay with him or her for any further treatment.
I had surgery first. That doctor didn't think I needed radiation, so I didn't get it. My cancer was back 6 weeks later. I went to a cancer care center where they did another surgery, followed by radiation and chemo. It's 2 years later and I'm doing pretty well now.
Yes, these surgeries caused life-altering changes in my life, but I have my life, and it's very worth it.
Good luck, and I'll be watching for your posts to see how you're doing.
Lani