Oral Cancer in the Dental Patient

Oral cancer is the sixth most common malignancy diagnosed in the United States. It represents 3 to 5% of all cancers in America. This translates in over 43,000 new cases of oral cancers yearly (1996 figures). In 1996 in the U.S., there were 8,260 deaths directly attributed to oral cancer. In the state of Georgia, 680 new cases of oral cancer were diagnosed, and 190 deaths occurred from oral cancer in 1996.

As a disease, oral cancer is usually detected early and typically detected by dental professionals. Most patients are acutely aware of any problem in or around their oral cavity. Thankfully, these folks stop by to see the dentist, usually sooner versus later. Once in the dental chair, the dental professional can employ his or her superior knowledge of the oral cavity to render a diagnosis and appropriate referral as necessary.

Before one examines oral cancer, it is prudent to examine two more common conditions, which are considered precursors to oral cancer: leukoplakia and erythroplakia.

Leukoplakia is defined as "a white plaque that cannot be described otherwise." Its etiology can be trauma, tobacco or tertiary syphilitic glossitis. Clinically it is the most common oral precancerous lesion. Eighty-five percent of the patients diagnosed with oral cancer have been diagnosed with leukoplakia. Leukoplakia occurs typically in males more than females, and usually not until the fifth or sixth decade of life.

Leukoplakia locations vary. It may appear most anywhere in the oral cavity, but is most likely to occur on the vermilion of the lip, the buccal mucosa, and/or the mandibular gingiva. Of note, leukoplakia is much more likely to undergo malignant transformation in males over 40 years of age than females of the same age group.

Three histopathological grades of leukoplakia are Early, Moderate, and Severe. These grades are histopathologic interpretations of the degree of cellular dysplasia present in cancerous tissue.

The treatment for leukoplakia is to remove any obvious etiologic agent. Cessation of tobacco and/or alcohol use is highly desirable, but rarely accomplished. Lesions suspected, as leukoplakia should be biopsied to confirm the clinical diagnosis. After histopathologic confirmation, these lesions should be removed with a scalpel or a laser.

Since leukoplakia is benign condition, its prognosis is good. However, as stated earlier, the majority of leukoplakias become cancerous with the passage of time. Subsequently, close follow-up every three to six months after biopsy will remove what is mandatory.

Erythroplakia is defined as "a red plaque that cannot be described otherwise." Like leukoplakia, erythroplakia etiology is thought to be associated with tobacco use or trauma. Erythroplakia is much less common than leukoplakia, but far more likely to be malignant. It is typically located on the floor of the mouth, soft palate, retromolar pad, or tongue. Like leukoplakia, it occurs more often in men versus woman, and usually in the fifth to sixth decades. The treatment for erythroplakia is the same as leukoplakia. Remove any obvious etiologic agent, and once the diagnosis of erythroplakia is confirmed, histopathologically remove the suspicious lesion.

Verrucous carcinomas an exophytic, well differentiated form of oral cancer. Like squamous cell. Carcinoma, its etiology is trauma, tobacco use, and viral. Clinically, it represents seven percent of all oral cancers. Verrucous carcinoma occurs most often in those individuals over the age of seventy. It is more common in men verses women. The most common location for verrucous carcinomas is the buccal mucosa and gingiva. Treatment involves surgical removal of the diseased tissue. If the cancer is detected early, prognosis is favorable following resection.

Oral cancer can present as irregular, indurated, painful, painless, erythroplakia-like, leukoplakia-like, ulcerative, exophytic, or benign.

The etiology of oral cancers is varied. The two most important etiologic factors associated with oral cancer are the use/abuse of tobacco and/or alcohol. Patients who consume alcohol in greater than moderate quanties regularly, and/or use tobacco in any form on a regular basis are much more likely to develop cancer of the oral cavity in their lifetime. Other factors associated with oral cancer include the patient's age. Oral cancer in those less than 40 years of age is rare. Oral cancer is also tied to race with African-Americans being diagnosed with oral cancer more so than Caucasian Americans. The use of betel nut, primarily India/Pakistan is closely linked to oral cancer.

Oral cancer is most likely to occur on the tongue, floor of mouth, and buccal mucosa. On rare occasions does it appear elsewhere in the mouth.

Histopathologic grades of oral cancer include carcinoma in situ, mild, moderate and severe dysplasia. Carcinoma in situ is cancer confined above the basement membrane. Mild, moderate, and severe dysplasia refer to increasing grades of cancerous changes in cells located in the tissue.

Once oral cancer is diagnosed it is staged. The three factors involved in the staging process are tumor size, involvement of lymph nodes, and metastasis. The single most important factor in prognosis of a patient lies in early detection. The earlier the cancer is detected and treated the more favorable is the patient outcome.

Treatment for oral cancer involves radiation, chemotherapy or surgery.

Radiation alone has been proven effective in controlling and eliminating oral cancer in the early stages. It is delivered in divided doses to maximize its toxic effect on cancerous tissues while minimizing its effect on normal tissues. Radiation, especially in high doses, produces tissue fibrosis and scarring. Xerostomia secondary to destruction of salivary tissue is almost universal with radiation therapy and increases the incidence of caries in these patients.

Chemotherapy is often delivered to oral cancer patients as an adjuvent to radiation therapy and/or surgery. Sometimes chemotherapy is employed in attempts to decrease tumor size prior to surgery. If used during the immediate postoperative period, chemotherapy works to decrease the microscopic residual and micrometastatic disease. Lastly, chemotherapy for oral cancer can be employed as a palliative measure to attempt to improve the quality of the patient's life by decreasing pain and preventing obstruction of airway and/or esophagus. The most common chemotherapy agent employed today includes Cisplatin, Carboplatin, Fluorouracil and Methotrexate. All chemotherapeutic agents are associated with the undesirable side effects of nausea, vomiting, alopecia (hair loss), weight loss, bone marrow suppression, and xerostomia.

Surgical treatment of oral cancer varies widely and is dependent upon the stage of the disease at time of surgery. Smaller tumors can be removed easily with the scalpel or laser and leave a minimal defect. Larger tumors, and those tumors, in which there is lymph node involvement, require a much more aggressive surgical approach and typically leave a significant hard and soft tissue defect.

Treatment of dental patients suspected of having oral cancer begins with a through oral cancer screening where the hard and soft tissues of the oral cavity are inspected for any abnormal findings. If a suspicious area is discovered the dentist may elect to observe this area for up to a month, unless suspicion is high for oral cancer. The next step would be to have the area biopsied by an oral surgeon. Once the histopathological character of the tissue is discovered appropriate treatment can begin.