Should family physicians routinely examine the oral cavity to detect pre-cancers and cancers?
Screening by visual inspection of the oral cavity does not appear to reduce deaths from oral cancer in the general population, although there is some evidence that it could be effective in high-risk patients who use tobacco and alcohol. (Strength of Recommendation = B, based on inconsistent or limited-quality patient-oriented evidence)
An estimated one in 98 persons born in the United States will be diagnosed with a cancer of the oral cavity and pharynx during his or her lifetime, and nearly 8,000 persons died from oral cancer in 2010.1 At the time of diagnosis, about 50 to 60 percent of oral cancer cases have regional or distant metastases and are associated with poor survival. Approximately 80 percent of patients with oral squamous cell cancers have used tobacco products.2
In this Cochrane review, the authors searched multiple electronic databases for randomized controlled trials of screening for oral cancer and potentially malignant oral lesions that used visual examination or adjunctive screening aids (toluidine blue, fluorescence imaging, or brush biopsy) and that reported mortality outcomes.
Only one cluster randomized trial of visual screening met inclusion criteria. This trial, conducted in an area of India with a very high incidence of oral cancer compared with the United States, showed no statistical difference (relative risk = 0.79; 95% confidence interval, 0.51 to 1.22) in oral cancer mortality rates between the screened and the control groups. However, a post hoc subgroup analysis of participants who reported using tobacco and/or alcohol found a statistically significant reduced risk of death (relative risk = 0.66; 95% confidence interval, 0.45 to 0.95) in the screened group. The authors assessed this study as having a high risk of bias caused by lack of blinding in outcome assessment and failure to account for the effect of clustering on the results.
In 2004, the U.S. Preventive Services Task Force found insufficient evidence to recommend for or against screening adults for oral cancer.3 Despite inconclusive data that screening for oral cancer detects clinically significant lesions or improves health outcomes in U.S. populations, experts have suggested screening on other grounds: the test is noninvasive, takes relatively little time to perform, and may provide an opportunity to intervene at premalignant disease stages.4 However, as with screening tests for breast and prostate cancers, false-positive results and overdiagnosis (i.e., identification of premalignant lesions or indolent cancer that would not have affected a patient's health) may lead to anxiety and unnecessary treatment, potentially outweighing any small benefits. The examination also takes time that could be spent on other, potentially more useful interventions that improve patient outcomes.