The only thing that can prove cancer is a biopsy. Even that testing is subject to human error, but your doctor(s) may have a high opinion just on observation based on their experience. Mine wanted a biopsy for almost any suspicion be it a FNAB, punch, incisional or endoscopic biopsy under anesthesia, but my history with recurrences is different than most. Once an enlarged node wasn't biopsied right after treatment, and trusted the doctors opinion it was an inflammatory response. If I wasn't satisfied, I would go elsewhere and or see another one my doctors opinion or testing.

Good luck

10/09 T1N2bM0 Tonsil
11/09 Taxo Cisp 5-FU, 6 Months Hosp
01/11 35 IMRT 70Gy 7 Wks
06/11 30 HBO
08/11 RND PNI
06/12 SND PNI LVI
08/12 RND Pec Flap IORT 12 Gy
10/12 25 IMRT 50Gy 6 Wks Taxo Erbitux
10/13 SND
10/13 TBO/Angiograph
10/13 RND Carotid Remove IORT 10Gy PNI
12/13 25 Protons 50Gy 6 Wks Carbo
11/14 All Teeth Extract 30 HBO
03/15 Sequestromy Buccal Flap ORN
09/16 Mandibulectomy Fib Flap Sternotomy
04/17 Regraft hypergranulation Donor Site
06/17 Heart Attack Stent
02/19 Finally Cancer Free Took 10 yrs