The oral cavity includes the lip; alveolar ridge, the area immediately behind the top front teeth; retromolar trigone, the small area behind the wisdom teeth; the floor of the mouth, the area under the tongue; the tongue itself; the buccal mucosa, the lining inside the lips and cheeks; and the hard palate. Studies show there is a strong link between smoking, alcohol consumption and disease development. Other factors include genetic susceptibility, diet (vitamin A deficiency), viruses (herpes simplex virus type 1), chronic irritants such as poor dental hygiene, and syphilis. Pathologically, the most common tumor type found in the oral cavity is squamous cell carcinoma.
Next to skin cancer, cancer of the lip is the second most common form of head and neck cancer. Most cancerous lip lesions occur on the lower lip, and the vast majority (90%) occur in men. Risk factors include smoking (cigarettes and pipes) and sun exposure. Although basal cell (small round cells found in the lower part, or base, of the epidermis, the outer layer of the skin) cancers can occur on the lip, the principal cancer is squamous cell carcinoma. The typical symptom an ulcerative lesion or an exophytic growth on the lower lip.
Cancers of the alveolar ridge and retromolar trigone account for approximately 10% of all oral cancers, or about 4,000 cases per year. Four times as many men are affected than women. Presenting symptoms usually include pain that is worsened by chewing. Other symptoms include loose teeth and intermittent bleeding. Nearly all of these cancers are squamous cell carcinomas.
Floor-of-the-mouth cancers tend to develop in individuals around age 60. Men again outnumber women by a factor of 3 to 1. These cancers account for 10% to 15% of all oral cavity cancers. They typically present as infiltrating lesions that are very painful. Overall prognosis generally is determined by the disease’s stage, with early stages showing better prospects for recovery than later stages.
Cancers of the tongue account for roughly 15% of all oral cavity cancers. The average age at diagnosis is 60, and men are diagnosed three times more often than women. Tongue cancers, like most other oral cavity cancers, can grow in either an infiltrative or exophytic pattern. In most patients the primary presenting symptom is pain. Cancers of the tongue have a high risk of early lymph node involvement, and can spread to lymph nodes on both sides (bilateral) simultaneously in up to 25% of patients.
Tumors of the hard palate account for 5% of all oral cavity malignancies. They occur in men eight times more commonly than in women. Unlike most other sites in the oral cavity, squamous cell carcinoma of the hard palate accounts for only about 50% of all tumors. The remainder are made up of tumors of the minor salivary glands, such as adenoid cystic and adenocarcinoma (cancer derived from cells of glandular origin).
Cancer of the buccal mucosa (lining inside the lips and cheeks) are often exophytic in nature. The presenting symptoms are usually pain, followed by bleeding and difficulty chewing.
Staging
See Staging for general staging rules. Oral cavity tumors are staged as follows:
– TX Primary tumor cannot be assessed
– T0 No existence of primary tumor
– Tis Carcinoma in situ
– T1 Tumor 2 cm or less in greatest dimension
– T2 Tumor more than 2 cm but not more than 4 cm in greatest dimension.
– T3 Tumor more than 4 cm in greatest dimension.
– T4 (lip) Tumor invades adjacent structures (e.g. through cortical bone, tongue, or skin of neck).
– T4 (oral cavity) Tumor invades adjacent structures (e.g. through cortical bone, into deep muscle of tongue, maxillary sinus, or skin).
Treatment
Lips
For early disease, either surgery or radiation is the mainstay of treatment. The choice of one over the other depends on the size and location of the disease. Given the infrequency of spread to the lymph nodes, elective treatment of the neck is not necessarily required. In advanced disease (Stages 3 and 4), a combination of surgery and postoperative radiation is often required.
Carcinoma of the upper lip. Resection and reconstruction
with lateral flaps (Burow technique).
Alveolar Ridge and Retromolar Trigone
In early disease (Stages 1 and 2) surgery or radiation alone with elective neck treatment (secondary to the tendency for regional nodal spread) is most often utilized. For advanced stages, multimodality therapy with surgery and postoperative radiation is often used.
Left mandibular carcinoma, hemimandibular resection, radical neck dissection. Reconstruction: endoprosthesis and temporalis muscle flap (in selected cases microsurgery may be used).
Floor of Mouth
Treatment of early disease (Stage 1 and 2) involves surgical resection. However, either surgery or radiation as single modalities of therapy may be utilized. In early disease, the treatment of the neck is controversial; some opt for elective neck treatment in clinically negative necks, while others take a wait-and-see approach, with treatment reserved for those who show development of disease. For advanced disease (Stages 3 and 4), combined modality treatment with surgery and radiation is recommended. Elective treatment of the neck is required in all cases of advanced disease.
Carcinoma of the tongue and floor, glossectomy, bilateral radical neck dissection. Reconstruction with endoprosthesis and pectoralis myocutaneous flap.
Tongue
Use of either surgery or radiation in early stage disease yields comparable outcomes. In advanced disease, as in other oral cavity cancers, combined modality therapy with surgery and radiation is utilized.
Hard Palate
For both early and advanced disease, surgery is used for primary therapy. Radiation has a role in advanced disease, depending upon the closeness or involvement of surgical margins by tumor, evidence of nerve involvement or the presence of lymph node metastases.