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 erythroplakia lesions, which can progress to cancer.[8,9] One study has shown that direct fluorescence visualization (using a simple hand-held device in the operating room) could identify subclinical high-risk fields with cancerous or precancerous changes extending up to 25 mm beyond the primary tumor in 19 of 20 patients undergoing oral surgery for invasive or in situ squamous cell tumors. However, this finding has not yet been tested in a screening setting. Data suggest that molecular markers may be useful in the prognosis of these premalignant oral lesions.
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 oral cancer mortality, and there are no randomized controlled trials (RCT) in any Western or other low-risk populations.[9,12,13,14,15]
In a single RCT of screening versus usual care, 13 geographic clusters in the Trivandrum district of Kerala, India, were randomly assigned to receive systematic oral visual screening by trained health workers (seven screened clusters, six control clusters) every 3 years for four screening rounds during the period 1996 to 2008. During a 15-year follow-up period, there were 138 deaths from oral cancer in the screening group with a cause–specific mortality rate of 15.4 per 100,000 person-years, and 154 deaths in the control group with a mortality rate of 17.1 per 100,000 person-years (relative risk [RR] = 0.88; 95% confidence interval [CI], 0.69–1.12). In a subset analysis restricted to tobacco or alcohol users, the mortality rates were 30 and 39 per 100,000 person-years, respectively (RR = 0.76; 95% CI, 0.60–0.97). There was no apparent adjustment of the CIs for the cluster design. In another subgroup analysis, mortality hazard ratios were calculated for groups defined by number of times screened, but the inappropriate comparison in each case was to the control group of the whole study. No data on treatment of oral cancers were presented.[16,17,18,19]