Epidemiological methods are essential for the discovery of cancer risks and prognostic factors as well as for the evaluation of cancer prevention measures. In this review, we discuss epidemiological surveillance procedures for data collection and processing ...

Small non-coding regulatory RNAs control cellular functions at the transcriptional and post-transcriptional levels. Oral squamous cell carcinoma is among the leading cancers in the world and the presence of cervical lymph node metastases is currently its strongest prognostic factor. In this work we aimed at finding small RNAs expressed in oral squamous cell carcinoma that could be associated with the presence of lymph node metastasis. Small RNA libraries from metastatic and non-metastatic oral squamous cell carcinomas were sequenced for the identification and quantification of known small RNAs. Selected markers were validated in plasma samples. Additionally, we used in silico analysis to investigate possible new molecules, not previously described, involved in the metastatic process. Global expression patterns were not associated with cervical metastases. MiR-21, miR-203 and miR-205 were highly expressed throughout samples, in agreement with their role in epithelial cell biology, but disagreeing with studies correlating these molecules with cancer invasion. Eighteen microRNAs, but no other small RNA class, varied consistently between metastatic and non-metastatic samples. Nine of these microRNAs had been previously detected in human plasma, eight of which presented consistent results between tissue and plasma samples. MiR-31 and miR-130b, known to inhibit several steps in the metastatic process, were over-expressed in non-metastatic samples and the expression of miR-130b was confirmed in plasma of patients showing no metastasis. MiR-181 and miR-296 were detected in metastatic tumors and the expression of miR-296 was confirmed in plasma of patients presenting metastasis. A novel microRNA-like molecule was also associated with non-metastatic samples, potentially targeting cell-signaling mechanisms. We corroborate literature data on the role of small RNAs in cancer metastasis and suggest the detection of microRNAs as a tool that may assist in the evaluation of oral squamous cell carcinoma metastatic potential.

Objectives: This study aimed to assess the hypothesis that recurrent denture-related sores association may be associated with the risk of oral cancer. Methods: We conducted a hospital-based case-control study comprising 71 new cases of oral cancer in two hospitals in São Paulo, Brazil, and 240 controls without cancer, recruited from outpatient units of the same hospitals. All cases had histologically confirmed squamous cell carcinoma in anatomic sites of the mouth that may be specifically consi-dered at risk of sores by ill-fitting dentures. Denture-related sores were assessed by the self-report of recurrent oral sores due to the use of ill-fitting complete removable dental prosthesis. Associations were assessed by multivariate logistic regression conditioned on socio-demographic and behavioral characteristics. Results: The association between ill-fitting dentures and oral cancer was statistically significant in the multivariate model: odds ratio 3.98; 95% confidence interval 1.06 - 14.96. The specific assessment of association between tumors in the lower jaw and sores by mandibular dentures confirmed this result: odds ratio 6.39; 95% confidence interval 1.49 - 29.52. Conclusion: The potential contribution of denture-related sores to oral carcinogenesis still fuels controversies. This study reinfor-ces the hypothesis that recurrent denture-related sores may be associated with the risk of oral cancer. Results reported here also suggest that an appropriate application and monitoring of dental prosthesis represent a non-negligible scope for cancer prevention.

Recent systematic reviews concluded that the frequent consumption of fruits and vegetables is inversely associated with the risk of oral cancer. We assessed this association, specifically comparing results obtained to nonsmokers and smokers, as well to nondrinkers and drinkers. We conducted a case-control study involving 296 patients with oral squamous cell carcinoma (cases) attended in 3 major hospitals of São Paulo, Brazil, paired with 296 controls, recruited from outpatient units of the same hospitals. Multivariate models assessed the effect of fruits and salads according to smoking and drinking. The intake of fruit was associated with the prevention of the disease in the specific assessment among light [odds ratio (OR) = 0.46; 95% confidence interval (CI) = 0.27–0.78) and heavy (OR = 0.30; 95% CI = 0.14–0.65) smokers. The same was observed for vegetables consumption. For nonsmokers, no fruit (OR = 50; 95% CI = 0.22–1.12) or vegetable (for tomato, OR = 0.53; 95% CI = 0.31–0.93) was associated with reduced risk of oral and oropharyngeal cancer. Similar results were found in the stratified analysis according to drinking status with OR = 0.51 (95% CI = 0.30–0.87) and 0.18 for fruits (95% CI = 0.07–0.45), respectively, for light and heavy drinkers. This observation suggests that the protective effect of fruit and salad intake may modulate the deleterious effects from tobacco and alcohol.

There are scarce epidemiological studies on lung cancer mortality in areas exposed to asbestos in developing countries. We compared the rates and trends in mortality from lung cancer between 1980 and 2016 in a municipality that made extensive use of asbestos, Osasco, with rates from a referent municipality with lower asbestos exposure and with the rates for the State of São Paulo. We retrieved death records for cases of lung cancer (ICD-9 C162) (ICD-10 C33 C34) from 1980 to 2016 in adults aged 60 years and older. The join point regression and age-period-cohort models were fitted to the data. Among men, there was an increasing trend in lung cancer mortality in Osasco of 0.7% (CI: 0.1; 1.3) in contrast to a mean annual decrease for Sorocaba of -1.5% (CI: −2.4; −0.6) and a stable average trend for São Paulo of -0.1 (IC: −0.3; 0.1). Similar increasing trends were seen in women. The age-period-cohort model showed an increase in the risk of death from 1996 in Osasco and a reduction for Sorocaba and São Paulo State during the same period. Our results point to a need for a special monitoring regarding lung cancer incidence and mortality in areas with higher asbestos exposure.

Objective. Evaluate the relationship between animal-derived foods and mouth and oropharyngeal cancer. Methods. Hospital-based case-control study matched by sex and age (+/- 5 years) with data collected between July of 2006 and June of 2008. The sample contained 296 patients with mouth and oropharyngeal cancer and 296 patients without a cancer history who were treated in four hospitals in the City of Sao Paulo, State of Sao Paulo, Brazil. A semistructured questionnaire was administered to collect data regarding socioeconomic condition and harmful habits (tobacco and alcoholic beverage consumption). To assess eating habits, a qualitative questionnaire that asked about the frequency of food consumption was used. The analysis was rendered by means of multivariate logistic regression models that considered the existing hierarchy among the characteristics studied. Results. Among foods of animal origin, frequent consumption of beef (OR = 2.73; CI95% = 1.27-5.87; P < 0.001), bacon (OR = 2.48; CI95% = 1.30-4.74; P < 0.001) and eggs (OR = 3.04; CI95% = 1.51-6.15; P < 0.001) was linked to an increased risk of mouth and oropharyngeal cancer, in both the univariate and multivariate analyses. Among dairy products, milk showed a protective effect against the disease (OR = 0.41; CI95% = 0.21-0.82; P < 0.001). Conclusions. This study affirms the hypothesis that animal-derived foods can be etiologically linked to mouth and oropharyngeal cancer. This information can guide policies to prevent these diseases, generating public health benefits.