Oral Cancer

1051

Accounts for 3 percent of cancers in men and 2 percent of cancers in women.

Most frequent malignancy of the head and neck region.

Incidence has decreased over the last decade.

Includes cancers of the lip, oral cavity, and pharynx.

Oral cavity cancer is the most frequent cause of cancer death in India and second most frequent in France secondary to use of cigarettes, smokeless tobacco and alcohol.

In 2020, cancer of the lip and oral cavity was estimated to rank 16th in incidence in mortality worldwide.

Oral cancer is a common cause of cancer deaths in men across much of the South and Southeast Asia and the western Pacific.

Expected 36,000 new cases of oral pharyngeal cancer in the U.S. in 2013, along with 6850 deaths.

Globally greater than 375,00  cases of oral cavity cancer per year.

Incidence rate of 10.5 cases per 100,000 population.

Prevalence is high in poor countries and survival is low in developed countries.

5-year cancer survival rates compared with other cancers is attributed to late diagnosis and results in late treatment of the disease.

There has been only a 5% improvement in overall survival in the last 20 years

Routine screening has not shown to reduce mortality from this disease.

5-year survival rate of less than 50% has not improved in more than 2 decades.

Relative five-year survival is 82.4% for localized disease and 33.2% for distant metastases.

Greater than 50% of patients with oral cancer have regional or distant metastases at the time of presentation.

Tobacco and alcohol use cause up to 75% of cases in the US, however incidence has decreased because of the decline in cigarette smoking and alcohol use.

Risks are dominated by tobacco both smoked and smokeless, and heavy alcohol consumption.

In Southeast Asia and Western Pacific Islands the incidence of oral cancer is high with major risk factors being the use of smokeless tobacco and areca nut products.

HPV virus accounts for a small percentage of oral cancer worldwide, approximately 2%, and primarily HPV 16.

The incidence of human papillomavirus and oral squamous cell carcinomas has increased.

Oral leukoplakia is the most common premalignant lesion of the oral cavity.

Neck tumor recurrence in procedures with clinically positive nodes is more than 6 times greater than in those with clinically negative nodes.

Only half of oral cancers develop at the site of leukoplakia.

Remains primarily a surgical disease because it is accessible, and because improvements in surgical technique involving resection, immediate reconstruction, followed by radiotherapy or chemoradiotherapy.

Incidence of occult metastases in early stage tumors T1-T2 reported in 27-40%.

When the risk of cervical lymph node involvement is greater than 15-20% an elective neck dissection is advocated.

Elective neck dissection provides diagnostic and therapeutic benefits by adding pathological information on the status of lymph nodes and helps to determine the need for adjuvant therapy.

Tumor thickness is a strong predictor for lymph node involvement (Asakage T).

For lesions with a tumor thickness of greater than 4 mm prophylactic neck dissection is recommended as a result of a meta-analysis (Shao Hui Huang).

State of the art treatment of patients with oral cancer and N1 to N3 regional lymph nodes metastases consists of neck dissection and postoperative radiotherapy.

For patients with oral cavity squamous cell carcinoma outcomes are improved with surgery first (Chinn SBP et al).

Local and neck recurrences are the most frequent sites of treatment failures in patients with oral cancer.

About one third of cases will fail with regional metastases.

Risk factors for recurrence after surgical resection include T classification, nodal neck metastases, surgical margins, depth of invasion and nerve invasion (Ooki A).

Cervical lymph node metastases are more likely to be found when nodal dissection includes 20 or more lymph nodes (Agrama MT).