The diagnostic process for oral cancer begins with a comprehensive physical examination. During routine check-ups, a dentist or doctor may detect abnormal tissue changes, potential lesions, lumps, or masses in the oral cavity, whether symptoms are present or not.

A definitive diagnosis is usually confirmed through direct examination of the lesion and taking a biopsy. Once diagnosed, further evaluations are conducted to determine the extent and size of the cancer. These additional tests may include:

* MRI (Magnetic Resonance Imaging) scan of the head and neck
* CT (Computed Tomography) scan of the chest to check for cancer spread in the lymph nodes
* PET (Positron Emission Tomography) scan to investigate possible cancer spread to other parts of the body

Additionally, a doctor may perform an endoscopy or laryngoscopy procedure, guiding a flexible tube with a small camera down the throat to closely examine the larynx, esophagus, and lungs.