Oral cancers are the most common in the head and neck region and are frequently — but not always — associated with exposure to tobacco and alcohol. While the majority of patients are diagnosed with squamous cell cancer of the lining of the mouth, there are other types of tumors that arise from the salivary glands that are located beneath the lining of the mouth known as the mucosa of the oral cavity.
The most common sites for squamous cell cancer include the mobile tongue and the floor of the mouth. The inside of the cheek (mucosa) and the gums (gingiva) may also be the site of origin for oral malignancies. In select circumstances, squamous cell cancers may arise from the sockets of a tooth in the mandible or maxilla. Alternatively it may arise from the maxillary sinus or the nasal cavity and grow downward to involve the palate. Rare forms of salivary gland tumors, as well as squamous cell cancers, may actually arise in the bone of the jaws. In addition there are primary bone tumors, known as osteogenic sarcomas, that arise directly from the mandible and less commonly the maxilla.
Treatment of oral cancers: Unlike treatment for cancers of the throat and larynx, the primary treatment for oral cancer is the surgical removal of the tumor followed by radiation — along with chemotherapy in select circumstances. The surgical management of oral cancer often involves a plan for reconstruction of the region of the mouth from which the tumor is removed, which most often is performed at the same time that the ablative portion of the procedure is performed.
Cancers throughout the body are “staged” for the purpose of communicating the extent of the disease and determining the prognosis following treatment, and to assist in determining the optimal treatment plan. The stages of oral cancer are based on the surface extent of the tumor, the depth of the invasion, and involvement of both the underlying bone and lymph nodes in the neck. Pre-malignant lesions known as dysplasia and cancer in situ are commonly found and require therapeutic intervention in order to avoid the progression to invasive cancer. Imaging studies such as CT scans, MRIs, panorex and PET/CT scans can be very helpful in diagnosing the full extent of a tumor, including involvement of bone, as well as in determining if lymph nodes are involved.
The goal of treatment is to completely resect the tumor with a margin of healthy tissue surrounding it — which may involve the removal of portions of the tongue, the floor of the mouth and the cheek, as well as segments of the mandible and palate. Depending on the extent of the tumor, removal of the mandible may be accomplished with only a partial removal of the thickness of the bone (marginal mandibulectomy). In other circumstances, a segmental resection of the bone of the jaw is required.
The reconstruction of soft tissue defects may be accomplished using sophisticated techniques that can transfer bone and tissue from other parts of the body to restore the look and function of the face. These techniques involve the use of microvascular surgery and have revolutionized the management of oral cancer, allowing reconstruction to be accomplished, restoring facial function and preserving facial form.
Lymph node metastases are commonly found in patients who are diagnosed with oral cancer. Management of the neck and cervical lymph nodes often requires the performance of a prophylactic neck dissection so that the stage of the disease is understood to determine if there is a necessity for radiation and/or chemotherapy. Therapeutic neck dissections should be performed in patients who have been identified with nodal metastases based on imaging studies or on a physical examination.
The prognosis for patients with oral cancer depends upon the stage of the disease at the time of diagnosis. Appropriate management requires multidisciplinary intervention by experienced oral pathologists, head and neck surgeons, medical oncologists, and diagnostic head and neck radiologists.