Abstract
OBJECTIVE: To investigate the frequencies and bacterial load of three species of periodontal bacteria in samples from oropharyngeal cancer patients versus healthy individuals. STUDY DESIGN: This is a case-control study based on biopsies collected from tumor tissues obtained from patients with oropharyngeal squamous cell carcinoma between 2016 and 2017 and shed oral mucosal epithelial cells that were collected from controls using the Cepimax® brush, carrying out several brushings towards the posterior third edge of the tongue and the cheek. Porphyromonas gingivalis, Tannerella forsythia and Prevotella intermedia detection and absolute quantification was determined through q-PCR. Statistical analysis included a U- test, X (2) , Fisher's exact test, odds ratio (OR) and Conditional logistic regression analysis and unconditional regression analysis (p < 0.05). RESULTS: A total of 48 donors older than 55 years old participated in this study. The population was distributed into 24 patients (cases) and 24 controls. A robust association was established in cases and controls with significance regarding Prevotella intermedia (OR: 15.00) and Porphyromonas gingivalis (OR:11.00). In the comparison between the amount of each bacteria in the groups, P. intermedia showed a higher bacterial load in oropharyngeal cancer patients (p = 0.04). However, multivariate analysis adjusted to the presence of different bacteria and the diverse confounding variables did not reveal significant differences for oropharyngeal cancer association. CONCLUSION: P. gingivalis and P. intermedia were detected more frequently in the group of patients with cancer. The bivariate analysis of the bacterial load evidenced significant differences for Prevotella intermedia, suggesting that it could be associated with oropharyngeal cancer.