Let me just throw in my experience ...

I was initially T1/2 N0M0 with tumor on my tongue ... had surgery in October 2003 and followed with radiation in December 2003-January 04 ... six months later I go back for follow-up and talk with my ENT about tenderness in my neck. He does a full physical exam, doesn't feel anything abnormal but didn't have a good feeling about it. So he orders a PET "for my peace of mind."

The PET revealed two hot spots, one in my neck and one somewhere in the roof of my mouth. I then go for an MRI, which also shows something irregular in my neck (but nothing abnormal in the other spot). They do a needle biopsy of the hot spot on my neck, and that came back negative for cancer but showed dead tissue. Still questionable.

My ENT, who is about my age (mid-30s) still doesn't have a good feeling, orders a surgery to remove the entire lymph node to get a look at everything. It turns out I had a tumor there about the size of a quarter. If not for his gut feeling and getting the PET, I may have let that tumor stay in there awhile before dealing with it. It came out, I went through more rad and chemo, and am still kicking now ...

I moved across the country and my new ENT doesn't order PETs and pretty much told me they are too expensive. My former ENT likes them if they give you peace of mind.

I had one anyway a few months after my second round of treatments ended as well as an MRI a few months after that. So far so good -- negative for cancer ... I'll likely want to get a PET again sometime soon since it's been more than a year, again for that peace of mind thing and because I am concerned about distant mets... Still going to the doc every 3-4 months for physical exam as well, trying to keep all bases covered ...