***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Approximately 3,000 new cases of oral cancer are diagnosed each year in Canada . Most of these cases occur among older adults with a history of tobacco use or excessive alcohol consumption . Preventive interventions for oral cancer include counselling of patients to modify risk factors and screening to identify precancerous and early-stage lesions . This report presents evidence -based guidelines on the prevention of oral cancer and precancer among asymptomatic patients . METHODS Literature search es of the 1966 - 1999 MEDLINE and CANCERLIT data bases were completed using the major MeSH heading mouth neoplasms . References from articles and recommendations of organizations were also review ed . The evidence -based methods of the Canadian Task Force on Preventive Health Care were used to assess evidence and to develop guidelines . Advice from experts and other recommendations were taken into consideration . RESULTS In cohort and case-control studies , smoking cessation decreased the risk of oral cancer and precancer . R and omized controlled trials ( RCTs ) indicate counselling by trained health care professionals is effective in promoting smoking cessation . Although counselling has been effective for the reduction of excessive alcohol consumption in RCTs , no studies have examined whether alcohol reduction reduces the risk of oral cancer or precancer . The usefulness of general population screening is limited by the low prevalence and incidence of the disease , the potential for false-positive diagnoses and the poor compliance with screening and referral . There is no evidence that screening of the general population or high-risk groups leads to a reduction in mortality or morbidity from oral cancer . INTERPRETATION There is good evidence to specifically consider smoking cessation counselling in a periodic health examination ( grade A recommendation ) . For population screening , there is fair evidence to specifically exclude screening for oral cancer ( grade D recommendation ) . For opportunistic screening during periodic examinations , there is insufficient evidence to recommend inclusion or exclusion of screening for oral cancer ( grade C recommendation ) . For patients at high risk , annual examination by physician or dentist should be considered . Risk factors include tobacco use and excessive consumption of alcohol . These recommendations are similar to those made by the Canadian Task Force on the Periodic Health Examination in 1994 and by the U.S. Preventive Services Task Force in 1996 A r and omized intervention trial is in progress in Kerala , India , to evaluate the effectiveness of oral visual inspection by trained health workers ( HWs ) in the prevention of oral cancer . Fourteen health workers with college graduation as the basic qualification were trained in oral visual inspection  to identify oral cancers and precancers among the participants of the screening trial and to refer them for further confirmation and management . The aim of the present study was to evaluate the reproducibility and validity of the  screening test  provided by the health worker against the reference oral visual findings of three physicians . A total of 2069 subjects who had already been examined were re-examined by the health workers and physicians . The sensitivity and the specificity of the oral visual inspection were 94.3 % and 99.3 % respectively . There was moderate agreement between the findings of the initial and the repeat mouth examinations carried out by the health workers , which were on average 6 months apart . There was almost perfect agreement ( kappa = 0.85 ) between the findings of the health workers and the physicians in identifying the different types of oral precancerous lesions . The findings of our study indicate that it is possible to train re source persons to perform the oral cancer screening test as accurately as doctors , although experience appears to be a crucial component of health workers ' accuracy . The efficacy of such an approach to reduce the incidence of and mortality from oral cancer , however , remains to be proven Oral cancer is caused by chewing and smoking of tobacco . To assess the feasibility of primary prevention of oral cancer , two cohorts were studied in base-line surveys and then followed up annually for 10-yr in Ernakulam district of Kerala state . The intervention cohort consisted of 12212 tobacco users aged 15 yr and over , who were exposed to a concentrated program of education against tobacco use .  The control cohort was a non-concurrent cohort of 6075 tobacco users studied using similar methods but with a minimal amount of advice against tobacco use . The stoppage of tobacco use increased and the incidence rate of leukoplakia decreased significantly and substantially in the intervention cohort compared to the control cohort . The decrease in the incidence of leukoplakia was indicative of the decrease in the risk of oral cancer since the two were intimately related . This study demonstrated feasibility of primary prevention of oral cancer A cluster r and omized controlled oral cancer screening trial is on-going in the Triv and rum district , India , to evaluate the efficacy of screening in reducing oral cancer mortality . Subjects , aged 35 years and above , in 13 clusters in the Triv and rum district , India , were r and omized to the intervention ( screening ) group ( 7 clusters , 78969 subjects ) to receive three rounds of screening by oral visual inspection by trained health workers at 3-year intervals or to a control group ( 6 clusters , 74739 subjects ) . Two rounds of screening were completed between 1995 and 2002 during which 69896 ( 88.5 % ) subjects were screened at least once , and 59.7 % of the 4408 screen-positive subjects were further investigated . In the intervention group , 344404 person-years were accrued and 329326 person-years were in the control group . In the intervention group , 149 incident oral cancer cases and 65 deaths from oral cancer were observed , and 106 incident cases and 62 deaths from oral cancer were observed in the control group . The programme sensitivity for detection of oral precancerous lesions and cancer was 81.5 % and the programme specificity was 84.8 % ; the programme positive predictive value was 39.6 % . In the intervention group 37.6 % of the cases were in stages I-II , as opposed to 18.9 % in the control group . The 3 year survival rate was 57.5 % in the intervention and 38.8 % in the control group ( P<0.05 ) . The age st and ardized oral cancer mortality rates were 21.2/100000 person-years in the intervention and 21.3/100000 in the control group . After completing two rounds of screening , oral cancer mortality rates were similar in both study groups It is well established that most invasive oral cancers arise from precancerous lesions such as leukoplakia , erythroplakia and oral submucous fibrosis . One of the approaches for control of oral cancer is to detect oral precancerous lesions early in their development and prevent their malignant transformation to invasive cancer either by chemoprevention or by surgical excision of the lesions , with concurrent control of tobacco and alcohol use and other specific aetiological factors . However , the value of specific approaches such surgery in long-term control of lesions and prevention of malignant transformation is not known . We describe our experience with cold knife surgical excision of 59 cases of non-homogeneous leukoplakia of the oral cavity diagnosed in the context of a community-based oral cancer cluster r and omised oral cancer screening trial in Kerala , India . Two-thirds of these revealed  dysplasia on histology . After a minimum follow-up of 12 months ( range 12 - 37 months ) after surgical excision , 44 ( 74.8 % ) were remaining disease free with no evidence of recurrent/new lesions ; during follow-up , three ( 5 % ) developed new luekoplakic lesions , and six ( 10.1 % ) developed recurrent lesions , while six ( 10.1 % ) could not be traced after treatment . There was no event of malignant change during follow-up . The proportion of subjects remaining with no evidence of disease at 3 years by Kaplan-Meier method of analysis was 62.1 % ( 95 % CI : 0.36 - 0.87 ) . Accrual and long-term follow-up of large number of surgically treated cases may provide valuable leads to management policies of oral leukoplakia , since , as of now , the added value of specific treatments over and above primary prevention by tobacco and alcohol control remains to be established The aim of the study was to evaluate dental health care workers ' ability to recognise  oral cancer and pre-cancer from colour photographic slides . A set of 80 slides  was prepared , 40 were negative ( normal mucosa or lesions with no malignant potential ) and 40 were positive ( cancer or potentially malignant lesions ) . The slides were arranged in r and om order and projected in a st and ard format . The performance was evaluated in terms of mean sensitivity , specificity , mean correct score and likelihood ratio . There were no significant differences between the three groups of dentists ( consultants , juniors hospital dentists and general dentists ) , all performed better than the auxiliaries . The chances of a consultant making a correct decision were 5.5 times better than for an auxiliary and 2.7 times better than for a junior hospital dentist . The slide show enables a comparison of health care workers to be made and may be useful for the evaluation , training and calibration of examiners for an oral cancer screening programme BACKGROUND A study group composed of research ers from across the United States undertook a study to evaluate the sensitivity and specificity of OralCDx ( OralScan Laboratories Inc. ) , a computer-assisted method of analysis of the oral brush biopsy , in the detection of precancerous and cancerous lesions of the oral mucosa . METHODS The study group conducted a multicenter double-blind study comparing results of OralCDx analysis with those of scalpel biopsy of suspicious oral lesions , as well as using OralCDx on oral lesions that appeared benign clinical ly . RESULTS In 945 patients , OralCDx independently detected every case of histologically confirmed oral dysplasia and carcinoma ( sensitivity = 100 percent , false-negative rate = 0 percent ) . Every OralCDx " positive " result was subsequently confirmed by histology as dysplasia or carcinoma . The specificity for the OralCDx " positive " result was 100 percent , while the specificity for the OralCDx " atypical " results was 92.9 percent . In 4.5 percent of clinical ly benign-appearing lesions that would not have received additional testing or attention other than clinical follow-up , OralCDx uncovered dysplasia or carcinoma ( statistical sensitivity > 96 percent , P < .05 , n = 131 ; statistical specificity for the OralCDx " positive " result > 97 percent and for the " atypical " result > 90 percent , P < .05 , n = 196 ) . CONCLUSIONS The authors propose that this multicenter trial demonstrates that OralCDx is a highly accurate method of detecting  oral precancerous and cancerous lesions .  OralCDx can aid in confirming the nature of apparently benign oral lesions and , more significantly , revealing those that are precancerous and cancerous when they are not clinical ly suspected of being so . All OralCDx " atypical " and " positive " results should be referred for scalpel biopsy and histology to completely characterize the lesion . CLINICAL IMPLICATION S Given the difficulty in clinical ly differentiating premalignant and malignant lesions from benign lesions with a similar appearance , OralCDx appears to determine the significance of an oral lesion definitively and detect innocuous-appearing oral cancers at early , curable stages BACKGROUND Oral cancer screening procedures are design ed to collectively allow early detection of cancers in a body area accessible to visual and physical examination , as well as to facilitate timely treatment , awareness , and the ongoing education of the public . METHODS A state fair was selected for this activity because of the availability of a r and om population compatible with meeting these goals . A total of 1,151 individuals participated in this free elective activity .  RESULTS Of this number 4.17 % were deemed to have oral pathologic states necessitating professional intervention , and 1.82 % were clinical ly diagnosed as having potential dysplastic or precancerous lesions . No clinical oral cancer was detected in this population . Nevertheless , by virtue of screening and detecting clinical ly premalignant lesions , the screening test advanced the diagnosis of potential oral cancers . CONCLUSIONS The outcome adds support to oral cancer screening as a procedure applicable in reducing morbidity and mortality from oral cancers Oral cancer satisfies the criteria for a suitable disease for screening , and oral visual inspection is a suitable test for oral cancer screening . The efficacy of screening in reducing mortality from oral cancer has not yet been evaluated . The authors describe a cluster‐r and omized , controlled oral cancer screening trial in southern India and its early results The utilisation of primary health workers ( HWs ) for cancer control in developing countries has often been suggested , based on the experience of feasibility studies in India and Sri Lanka . We initiated a project in 1988 to evaluate the long-term feasibility of using trained HWs in secondary prevention of oral cancer , to bring about earlier detection of oral cancer in the communities served by them . Two hundred and eighty-two HWs attached to 14 primary health centres ( PHCs ) , serving approximately 0.92 million rural population in the northern half of Triv and rum district in Kerala , India , were trained in oral visual inspection to detect precancerous , malignant and other suspicious lesions of the oral cavity and refer them for confirmation and treatment . They were asked to examine subjects aged 35 years and above and to give person to person health education on tobacco in their target population . The HWs belonging to the PHCs serving approximately 1 million rural population in the southern half of Triv and rum district were not trained , and this region served 
    Output:
    
Given the limitation of evidence and the potential method ological weakness in the included study , it is valid to say that there is no evidence to recommend inclusion or exclusion of screening programs for oral cancer using visual examination in the general population .