Yes. They don't proclaim such statements lightly. Have they been wrong before? Sure. But most of the time, they know. 

I had the same question just 10 days ago or so. And doc was spot on. 

Don't panic. Take it one day at a time. 

Nothing will be known for certain until you get the biopsy results but you seem to be preparing for the worst, which is better than hiding your head in the sand.

Good luck
Dave 

As Lucullan said, they do get it wrong, and there are stories the internet over, but in the grand scheme of things, they're rare. They told my wife she had cancer before the biopsies came back, and we asked if they could be wrong. They said yes, but not to get your hopes up. They were right. They deal with this frequently.

However, there is still some hope as the only way they can be sure is via a biopsy.

Hi It's possible they have got it wrong. Sadly this part is the worst part the not knowing I am 4 years post radiotherapy and chemotherapy for tonsil cancer with several affected lymph nodes.  Head and neck cancers do have an excellent/cure rate. The treatments pretty brutal but the results  can be excellent in many case. Best advise keep off Dr Google you'll scare your self silly best advise my oncologist gave me. 
My blog  is www,radioactiveraz.wordpress.com  there's factual stuff that happened to me on there. 
my ent consultant first thought my lump could be been latent t b but the following week the look on her face said it all.

im happily living my life  if I can help just shout Hazel x

Thank you for reaching out! I have bloody researched it all, stupid me! I'm just shocked she came straight out with it. Wonderful to hear your good news xxx

Hi. Promise me you'll keep off Dr  Google. The info is unregulated unless you really know where to look. If I put survivor rate tonsil cancer  you get 40 % which is wzy off the 90-95 percent 5 year figure in. Those odds were given by my oncologist. This  part is by far the worst bit. It Human nature fear of the unknown. Keep busy don't turn to drink it won't do you any favours pick a good box set up or book. Let me knuw your results in meantime shout out if I can help. Hazel 

Still no word! 

I finally got through to the ENT Dept and my report from the mri came back on Friday. I've got an appointment with the consultant tomorrow...

Not what you want to hear but in my opinion if a specialist thinks it's cancer they are usually right  :-( my breast cancer nurse said my lump was cancer and it was and a friend only had a smear and the normal nurse told her she had cancer and she did 

I am in similar situation and can't help but panic. How did you get on?? Xxx