Tests and procedures used to diagnose mouth cancer include: Physical exam. Your doctor or dentist will examine your lips and mouth to look for abnormalities — areas of irritation, such as sores and white patches (leukoplakia). Removal of tissue for testing. If a suspicious area is found, your doctor or dentist may remove a sample of cells for laboratory testing in a procedure called a biopsy. Unusual cells can be scraped away with a brush or cut away using a scalpel. In the laboratory, the cells are analyzed for cancer or precancerous changes that indicate a risk of future cancer...Treatment for mouth cancer depends on your cancer's location and stage, as well as your overall health and personal preferences. You may have just one type of treatment, or you may undergo a combination of cancer treatments. Discuss your options with your doctor.