Deep lesions, of course, are more accurately evaluated on imaging as opposed to physical examination. The staging of oropharyngeal squamous cell cancer is based upon size of the tumor and invasion of adjacent structures. Therefore, one needs to pay particular attention to tumor extension to deep spaces, especially to the parapharyngeal, carotid, and prevertebral spaces. Evaluation of adenopathy should be made accordingly, particularly in the carotid space. Tongue base squamous cell cancer can also invade the adjacent deep spaces.
Perineural spread is also a possibility.
In addition, one should assess for midline crossing, as this can determine whether there can be a hemi rather than total glossectomy. Squamous cell cancer of the tongue base has the propensity to invade inferiorly into submandibular space and extend down to the vallecula and pre-epiglottic space directly. In addition, one should evaluate any oropharyngeal or orocavity cancer for mandibular invasion. Squamous cell cancer of the lip, particularly the lower lip, is the second most common site of squamous cell cancer of the head and neck, the skin being the most common. Squamous cell cancer of the lip can invade the buccal mucosa and the mandible as well as extending into deep spaces.