RESUMO
Cancers of the upper aerodigestive tract (UADT: oral cavity, oropharynx, hypopharynx, larynx, esophagus) have high incidence rates all over the world and they are especially frequent in some parts of Latin America. In this study, we have evaluated the role of the consumption of maté, a hot herb-based beverage, based on 1168 UADT squamous-cell carcinoma cases and 1,026 frequency-matched controls enrolled from four centers in Brazil and Argentina. The effect of maté drinking on the risk of head-and-neck cancers was borderline significant. A significant effect was observed only for cancer of the esophagus (OR 3.81 (95% CI 1.75-8.30)). While duration of maté drinking was associated with the risk of all UADT cancers, the association with cumulative maté consumption was restricted to esophageal cancer (p-value of linear trend 0.006). The analyses of temperature at which maté was drunk were not conclusive. The increased risk associated with maté drinking was more evident in never-smokers and never-alcohol drinkers than in other individuals. Our study strengthens the evidence of an association between maté drinking and esophageal cancer; the hypothesis of an association with other UADT cancers remains to be clarified.
Assuntos
Bebidas/efeitos adversos , Ingestão de Líquidos , Neoplasias Esofágicas/complicações , Neoplasias de Cabeça e Pescoço/complicações , Ilex paraguariensis/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Argentina/epidemiologia , Brasil/epidemiologia , Carcinoma de Células Escamosas/complicações , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/etiologia , Estudos de Casos e Controles , Neoplasias Esofágicas/epidemiologia , Feminino , Humanos , América Latina/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Multicêntricos como AssuntoRESUMO
Cancers of the upper aerodigestive tract [(UADT): oral cavity, pharynx, larynx and oesophagus] have high incidence rates in some parts of South America. Alterations in the TP53 gene are common in these cancers. In our study, we have estimated the prevalence and patterns of TP53 mutations (exons 4-10) in 236 UADT tumours from South America in relation to lifestyle risk factors, such as tobacco smoking and alcohol drinking. Moreover, we have conducted a pilot study of EGFR mutations (exons 18-21) in 45 tumours from the same population. TP53 mutation prevalence was high: 59% of tumours were found to carry mutant TP53. We found an association between TP53 mutations and tobacco smoking and alcohol drinking. The mutation rate increased from 38% in never-smokers to 66% in current smokers (P-value for trend = 0.09). G:C>T:A transversions were found only in smokers (15%). Alcohol drinkers carried more G:C>A:T transitions (P = 0.08). Non-exposed individuals were more probable to carry G:C>A:T transitions at CpG sites (P = 0.01 for never-smokers and P < 0.001 for never-drinkers). EGFR mutations were found in 4% of cases. Inactivation of TP53 by mutations is a crucial molecular event in the UADT carcinogenesis and it is closely related to exposure to lifestyle risk factors. EGFR mutations do not appear to be a common event in UADT carcinogenesis in this population.