There are many types of oral, aerodigestive tract conditions that may be an indication of cancer, pre-maligned condition, and others that may not be as likely that are seen on a visual and palpable inspection, flex scope, endoscopy, lyrgnoscapy, triple scope or pandemoscopy, and anything suspected should have a sample taken from. The only thing that can prove cancer is a biopsy. No scan is 100 percent accurate , PET/CT, MRI, CT, Sonogram, but each are used for different areas, reasons, sometimes combined, and are only as good as the doctor or tech interpreting them.

I don't know about treatment, well I actually do, and you don't want it, and should be avoided by at all costs by stopping smoking and other carcinogenic intake, and living a healthy life, but a positive aspect with SCCHN is that there is more a chance it's not cancer, which is not an easy process anyway, taking 10 mutations, and 100 or so genetic changes to get cancer.

Good luck, and hope you hear good news.