Oral Cancer

Most oral cancers are squamous cell carcinomas. Most are asymptomatic until they ulcerate or cause mechanical problems. Diagnosis is by biopsy. Treatment is usually surgery, with or without radiation therapy.

Geriatric Essentials

• Physical examination is a useful means of detecting oral cancer that should not be overlooked in elderly edentulous patients who are least likely to receive regular annual oral, head, and neck examinations by dentists.

The oral cavity is the most common site of head and neck cancer after the larynx. In 2005, oral cancer, which represents 3 to 5% of all forms of cancer, was diagnosed in about 28,000 people and caused almost 8000 deaths in the US. More than ½ of the cases occur in people > 65 yr; the median 5-yr survival rate is only about 50%. The male:female ratio, previously very high, is now about 2:1. Most oral cancers (> 90%) are squamous cell carcinomas. The remainder falls under the categories of salivary gland tumors and lymphoreticular cancers.

Alcohol and tobacco use are primary risk factors; smokeless (chewing) tobacco seems to increase risk for verrucous carcinoma (a highly differentiated variant of squamous cell carcinoma). Many oral cancers arise from white hyperkeratotic plaques collectively referred to as leukoplakia (see Photo 104-19), but about 80% of all leukoplakic lesions are benign. Erythroplakia, flat or eroded velvety red mucosal patches (see Photo 104-20), is another type of precancerous lesion. DNA of human papillomavirus 16 is detectable in up to 20% of oral cancers; infection may increase risk synergistically with alcohol and tobacco use.

Some oral cancers are metastases from distant sites (eg, lungs, breasts, lymph nodes). Hematologic cancers, especially lymphomas and leukemias, may also manifest in the mouth or neck before they manifest systemically.

Oral cancer most commonly begins on the floor of the mouth or on the tongue, oropharynx, and lips. Oral cancer in the buccal and labial vestibular areas is most common in smokeless tobacco users. The most common sites of metastasis are lungs, bone, and liver. Because the upper aerodigestive track is also exposed to tobacco and alcohol (field cancerization), oral cancer increases the risk of developing a second primary cancer of the mouth, pharynx, larynx, esophagus, or lungs by up to 33%.

Symptoms and Signs

Oral cancers are typically asymptomatic until they ulcerate or grow large enough to cause mechanical symptoms. The main sign is an ulcer or a red or white lesion in the mouth or throat or on the lips. Local induration, fixation, and numbness with lymphadenopathy suggest advanced cancer.

Diagnosis

Diagnosis is suspected by history and examination; biopsy is indicated to confirm the diagnosis when suspicious lesions persist for > 3 wk after potential causes are treated (eg, denture adjustments for suspected mechanical irritation). Staging involves imaging with CT or MRI to identify tumor size, involvement of locoregional lymph nodes and vital structures, and distal metastases. See the National Cancer Institute's stage information for lip and oral cavity cancer.

Prognosis

Prognosis depends on cancer stage. Early-stage oral cancers < 2 cm in diameter that do not involve the lymph nodes and that have not metastasized are easily cured; the 5-yr survival rate is > 80%. However, most oral cancers spread to lymph nodes before they are diagnosed. For patients with advanced oral cancer, the 5-yr survival rate is < 20%.

Treatment

Treatment is usually surgery with or without radiation therapy. Small tumors with minimal or no lymph node involvement are managed with surgery alone. More extensive cancers are surgically removed, and external beam radiation therapy (60 Gy) is given for about 6 wk. Chemotherapy with concomitant radiation therapy is frequently used for tumors with lymph node involvement and for large cancers that are nonresectable. Advanced nonresectable tumors may shrink after chemotherapy and radiation therapy, but the prognosis is poor.

Surgery and radiation therapy can cause permanent problems. For example, salivary glands are destroyed if they are exposed to > 25 Gy, and the risk of developing osteoradionecrosis of the mandible or maxilla is significantly increased if exposure is > 60 Gy. Caries, oral mucosal infections, trismus (caused by radiation-induced head and neck muscle loss and fibrosis), and dysphagia (caused by radiation-induced muscle loss and fibrosis, and salivary gland hypofunction) are also more common.

Patients should be instructed to abstain from tobacco and alcohol and should be checked for complications resulting from treatment and for cancer recurrence.

Advanced lesions often cause considerable pain, interfere with eating, and eventually may cause difficulty swallowing. Palliative treatment is required to minimize pain and suffering, maintain nutrition, and maximize quality of life.

Prevention

See the National Cancer Institute's summaries of evidence for screening, prevention, and treatment of lip and oral cavity cancer.

Oral cancers may be prevented by smoking and alcohol cessation. Annual physical examination of the head, neck, and mouth is probably not very sensitive or specific for detecting oral cancer but is recommended for detecting some cancers earlier than they would otherwise be diagnosed. This is particularly important for elderly edentulous patients, who are least likely to receive regular annual oral, head, and neck examinations by dentists. Because early-stage oral cancers have such dramatically better survival rates than late-stage oral cancers, regular examinations are beneficial in identifying early lesions and initiating less toxic cancer therapies.

This topic was last updated September 2005.