METHODS: This scoping review intended to investigate published studies on the current prevalence and incidence of oral cancer in LMICs. The review was conducted applying the search words "Oral Cancer" and "Mouth neoplasm" as the Medical Subject Heading (MeSH) major topic and "Epidemiology" and ("prevalence" OR "incidence") as the MeSH subheading; the search was supplemented by cross-references. Included studies met the following criteria: original studies, reporting of prevalence or incidence rates, population-based studies, studies in English language and studies involving humans.
RESULTS: The sample sizes ranged from 486 to 101,761 with 213,572 persons included. Buccal mucosa is one of the most common sites of oral cancer, associated with the widespread exposure to chewing tobacco. The incidence is likely to rise in the region where gutkha, pan masala, pan-tobacco and various other forms of chewing tobacco are popular.
CONCLUSION: This review contributes to useful information on prevalence and incidence estimates of oral cancer in LMICs.
METHODS: This retrospective case-control study involves 790 cases of cancers of the oral cavity and 450 controls presenting with non-malignant oral diseases, recruited from seven hospital-based centres nationwide. Data on risk habits (smoking, drinking, chewing) were obtained using a structured questionnaire via face-to-face interviews. Multiple logistic regression was used to determine association between risk habits and oral cancer risk; chi-square test was used to assess association between risk habits and ethnicity. Population attributable risks were calculated for all habits.
RESULTS: Except for alcohol consumption, increased risk was observed for all habits; the highest risk was for smoking + chewing + drinking (aOR 22.37 95% CI 5.06, 98.95). Significant ethnic differences were observed in the practice of habits. The most common habit among Malays was smoking (24.2%); smoking + drinking were most common among Chinese (16.8%), whereas chewing was the most prevalent among Indians (45.2%) and Indigenous people (24.8%). Cessation of chewing, smoking and drinking is estimated to reduce cancer incidence by 22.6%, 8.5% and 6.9%, respectively.
CONCLUSION: Ethnic variations in the practice of oral cancer risk habits are evident. Betel quid chewing is the biggest attributable factor for this population.
MATERIALS AND METHODS: A total of 81 cases of oral cancers were matched with 162 controls in this hospital-based study. Information on sociodemographic characteristics and details of risk habits (duration, frequency and type of tobacco consumption and betel quid chewing) were collected. Association between smoking and betel quid chewing with oral cancer were analysed using conditional logistic regression.
RESULTS: Slightly more than half of the cases (55.6%) were smokers where 88.9% of them smoked kretek. After adjusting for confounders, smokers have two fold increased risk, while the risk for kretek consumers and those smoking for more than 10 years was increased to almost three-fold. Prevalence of betel quid chewing among cases and controls was low (7.4% and 1.9% respectively). Chewing of at least one quid per day, and quid combination of betel leaf, areca nut, lime and tobacco conferred a 5-6 fold increased risk.
CONCLUSIONS: Smoking is positively associated with oral cancer risk. A similar direct association was also seen among betel quid chewers.