The burden of potentially HPV-linked head and neck cancers in São Paulo, Brazil

Abstract

Approximately 570,000 new cases of cancer of the head and neck (mouth, oropharynx, hypopharynx and larynx) are diagnosed annually worldwide, accounting for 5% of all tumors. The city of São Paulo reports high incidence rates of cancers of the mouth and oropharynx (18.1 / 100,000 for males and 4.1 per 100,000 for females), corresponding to the 8th largest global rate among men and 17th for women. Among the risk factors for the development of these cancers, alcohol and tobacco are the most known and important. In some countries, has been registered an increase in incidence rates, particularly among young people and among non-drinkers and non-smokers. These trends have increased the debate about the role of human papillomavirus (HPV) in the etiology and several studies suggest that infection may play a causative role in a subgroup of tumors, predominantly in the oropharynx. In this context, the assessment of the magnitude and trends is needed, so that in future it is possible to assess the potential impact of HPV vaccination on the incidence of these cancers. Objectives: This study aims to assess the magnitude of cancers potentially related to HPV in São Paulo. Methods: This is a ecological study of time series that include in the analysis of incidence, new cases of cancer of the mouth or oropharynx, registered in the population-based cancer registry of São Paulo (RCBP-SP), diagnosed in the period between 1997 and 2004 and, for the analysis of mortality, deaths registered in the Mortality Information System (SIM) for the residents of São Paulo, from 1980 to 2007, whose underlying cause was cancer of the mouth or oropharynx. Incidence and mortality rates will be described for every 100,000 inhabitants, according to tumor site, age and sex. Annual percentage change (Annual Percent Changes - APC) in incidence and mortality rates will be calculated through Joinpoint modeling method, using the calendar year as regressor variable. The null hypothesis that the APC = 0 is rejected if the p value is less than 0.05. Statistical analysis will be carried out with the aid of the software Stata for Macintosh, Microsoft Excel and Joinpoint Regression Program version 3.3. (AU)