Why do you get a foreign body sensation in throat with mouth cancer, is it constant? and what are other symptoms

No symptoms: Early oral cancer does not have any symptoms . It will appear as a white or red spot in your mouth. By the time there are any symptoms a cancer can be more advanced and treatment more difficult. Smoking is one cause so quit no that is why routine dental exams are so very important. Your dentist should be doing a oral cancer examination at every examination and when you have your teeth cleaned.

Mouth cancer: Oral cancer can feel like a swelling or an inflammation. There are many, varied symptoms that are not all always present. I would strongly recommend seeing a dentist, rather than trying to diagnose oral cancer yourself.

Signs/Symptoms: See oral surgeon or ENT doc if you have any of these symptoms: Persistent mouth sore, persistent mouth pain, a lump or thickening in the cheek, a white/red patch on the gums, tongue, tonsil, or lining of the mouth, a sore throat, hoarseness or feeling that something is caught in the throat that does not go away, difficulty swallowing/chewing.