Like many other questions in medicine and health, the answer needs to be tailored to the specific circumstances for each patient. There are different subsites in the throat. Therefore the factors for risk assessment and symptoms are different. The ENT evaluation would include transnasal endoscopy and might require imaging (ultrasound, CT or MRI) of the neck.
In general, I would consider the following symptoms suspicious for cancer:
- smoking
- consistent high alcohol intake
- bloodstained sputum
- progressive hoarseness
- noisy breath sounds from the throat
- progressive swallowing difficulty
- palpable lump in the neck
However, early tumours may have very few symptoms and will need a thorough evaluation and follow up.