Oral Cancer Screening (PDQ®): Screening - Health Professional Information [NCI]
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Oral Cancer Screening
Purpose of This PDQ Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about oral cancer screening. This summary is reviewed regularly and updated as necessary by the PDQ Screening and Prevention Editorial Board.
Information about the following is included in this summary:
- Oral cancer incidence and mortality statistics and information about oral cancer risk factors.
- Oral cancer screening modalities.
This summary is intended as a resource to inform clinicians and other health professionals about currently available oral cancer screening modalities. The PDQ Screening and Prevention Editorial Board uses a formal evidence ranking system in reporting the evidence of benefit and potential harms associated with each screening modality. It does not provide formal guidelines or recommendations for making health care decisions. Information in this summary should not be used as a basis for reimbursement determinations.
This summary is also available in a patient version, which is written in less technical language.
Summary of Evidence
Note: Separate PDQ summaries on Oral Cancer Prevention and Lip and Oral Cavity Cancer Treatment are also available.
There is inadequate evidence to establish that screening would result in a decrease in mortality from oral cancer.
Description of the Evidence
- STUDY DESIGN: Evidence obtained from one randomized controlled trial.
- INTERNAL VALIDITY: Poor.
- CONSISTENCY: Not applicable.
- MAGNITUDE OF EFFECTS ON HEALTH OUTCOMES: No evidence of benefit or harm.
- EXTERNAL VALIDITY: Poor.
An estimated 35,720 new cases of oral cancer are expected to be diagnosed in the United States in 2009, and an estimated 7,600 people will die of the disease. This form of cancer accounts for about 3% of cancers in men  and 2% of cancers in women. Oral cancer occurs more frequently in blacks than in whites.
More than 90% of oral cancers occur in patients older than 45 years. The incidence increases steadily until age 65 years, when the rate levels off. Over the last 22 years, there have been slight decreases in incidence and mortality rates. Reports have noted a substantial increase in the incidence of oral cancer (particularly of the tongue) among adults younger than 40 years in the United States between 1973 and 1997.
The primary risk factors for oral cancer in American men and women are tobacco (including smokeless tobacco) and alcohol use. Infection with human papillomavirus 16 has been associated with an excess risk of developing squamous cell carcinoma of the oropharynx.
No population-based screening programs for oral cancers have been implemented in developed countries, although "opportunistic screening" has been advocated.[6,7] There are different methods of screening for oral cancers. Oral cancer occurs in a region of the body that is generally accessible to physical examination by the patient, the dentist, and the physician, and visual examination is the most common method used to detect visible lesions. Other methods have been used to augment clinical detection of oral lesions and include toluidine blue, brush biopsy, and fluorescence staining.
Screening examination can be made more efficient by inspecting the high-risk sites where 90% of all oral squamous cell cancers arise: the floor of the mouth, the ventrolateral aspect of the tongue, and the soft palate complex. An inspection of the oral cavity is often part of a physical examination in a dentist's or physician's office. It has been pointed out that high-risk individuals visit their medical doctors more frequently than they visit their dentists. Although physicians are more likely to provide risk-factor counseling (such as tobacco cessation), they are less likely than dentists to perform an oral cancer examination. Overall, only a fraction (~20%) of Americans receive an oral cancer examination. Black patients, Hispanic patients, and those who have a lower level of education are less likely to have such an examination, perhaps because they lack access to medical care. An oral examination often includes looking for leukoplakia and erythroplastic lesions, which can progress to cancer. One recent study has shown that direct fluorescence visualization (using a simple hand-held device) could identify subclinical high-risk fields with cancerous or precancerous changes in the oral mucosa. However, this finding has not yet been tested in a screening setting. Recent data suggest that molecular markers may be useful as markers of prognosis for these premalignant oral lesions.
Although it is possible to detect and cure early-stage oral cancers, most oral cancers are moderately advanced (regional stage) at the time of diagnosis. Unfortunately, this pattern has not changed over time.
Evidence of Benefit
The routine examination of asymptomatic and symptomatic patients can lead to detection of earlier stage cancers and premalignant lesions. There is no definitive evidence, however, to show that this screening can reduce mortality.[1,2]
In Sri Lanka and India, three large studies of screening for oral cancer (involving more than 250,000 patients) have shown that it is possible for primary health care workers to detect premalignant lesions and early cancers in these populations at high risk due to habits of tobacco and betel nut chewing and reverse smoking (placing the lit end of the cigarette in the mouth).[3,4,5] The general results of these studies were as follows: (1) 12% to 26% of screened participants had oral lesions that did not require referral to a specialist; (2) 1.3% to 4.2% of screened patients had referable oral mucosal lesions, and of these, 45% to 80% were correctly referred; (3) the false-positive rate ranged from 9% to 29%; and (4) primary health care workers detected a total of 44 new oral cancers.
Compliance rates of these studies varied from 54% to 72%, and poor compliance following initial screening make feasibility of these types of studies uncertain. Health education programs only marginally increased compliance rates. Compliance problems of the Indian and Sri Lankan studies are likewise a possibility in the United States and other countries, which also have experienced suboptimal compliance among high-risk tobacco and alcohol users. Contradictory oral cancer screening recommendations have been issued by the U.S. Preventive Health Services Task Force (against) and the American Dental Association (for). Oral exfoliative cytology is the most extensively studied screening procedure of U.S. oral screening programs. Problems encountered with this screening method include a high proportion of false-negative examinations and poor voluntary participation by the highest-risk individuals (heavy tobacco and alcohol users). New screening techniques using brush biopsy have been developed. Despite limitations, these techniques have improved the sensitivity (92.3%) (95% CI, 74.9–99.9%) and specificity (94.3%) (95% CI, 86.0–98.4%) for detection of oral squamous cell carcinoma or dysplasia when tested on visually identified lesions.[7,8]
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Changes To This Summary (06 / 30 / 2009)
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Updated incidence and mortality estimates for 2009 (cited American Cancer Society as reference 1).
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ADDITIONAL PDQ SUMMARIES
- PDQ® Cancer Information Summaries: Adult Treatment
Treatment options for adult cancers.
- PDQ® Cancer Information Summaries: Pediatric Treatment
Treatment options for childhood cancers.
- PDQ® Cancer Information Summaries: Supportive and Palliative Care
Side effects of cancer treatment, management of cancer-related complications and pain, and psychosocial concerns.
- PDQ® Cancer Information Summaries: Screening/Detection (Testing for Cancer)
Tests or procedures that detect specific types of cancer.
- PDQ® Cancer Information Summaries: Prevention
Risk factors and methods to increase chances of preventing specific types of cancer.
- PDQ® Cancer Information Summaries: Genetics
Genetics of specific cancers and inherited cancer syndromes, and ethical, legal, and social concerns.
- PDQ® Cancer Information Summaries: Complementary and Alternative Medicine
Information about complementary and alternative forms of treatment for patients with cancer.
This information is intended mainly for use by doctors and other health care professionals. If you have questions about this topic, you can ask your doctor, or call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
Date Last Modified: 2009-06-30