Bacterial Species Associated With Chronic Inflammation and Oral Cancer. A Comparative Study Between Patients With HNC and Patients With Chronic Periodontitis
Tanya Pereira‐Riveros, José López‐López, Alicia Lozano‐Borbalas, Julio Paciello‐Coronel, Teresa VinuesaABSTRACT
Objective
To compare the presence and quantification of selected periodontopathogenic bacterial species and salivary parameters between patients with head and neck cancer (HNC) treated with radiotherapy and patients with chronic periodontitis, using chronic periodontitis as a reference model of oral dysbiosis.
Methods
An analytical observational case–control study was conducted, including 61 patients diagnosed with HNC previously treated with radiotherapy and 36 patients with chronic periodontitis. Gingival crevicular fluid samples were collected for the quantification of total bacterial load, Porphyromonas gingivalis , Fusobacterium nucleatum , Campylobacter rectus and Aggregatibacter actinomycetemcomitans using conventional microbiological culture and quantitative polymerase chain reaction (qPCR). Stimulated and unstimulated salivary flow rates, as well as salivary pH, were also evaluated. Comparisons between groups were performed using parametric and non‐parametric tests according to data distribution.
Results
Patients with HNC exhibited a significant reduction in both stimulated and unstimulated salivary flow rates compared with patients with chronic periodontitis ( p < 0.001 for both comparisons). Significant differences in salivary pH were also observed ( p < 0.001). Microbiological analysis showed significantly lower levels of P. gingivalis and C. rectus in patients with HNC than in periodontal controls, as determined by both microbiological culture and qPCR ( p < 0.001). No significant differences were observed in total bacterial load, F. nucleatum or A. actinomycetemcomitans . Overall, microbiological differences between groups were limited to specific bacterial species rather than to the total bacterial load.
Conclusions
Patients with HNC treated with radiotherapy exhibit marked salivary alterations and differences in the quantification of specific periodontopathogenic bacteria compared with patients with chronic periodontitis. The persistence of F. nucleatum at levels comparable to those observed in an established model of chronic inflammation and oral dysbiosis suggests that this species may represent a stable component of the oral ecosystem associated with head and neck cancer. Longitudinal studies are required to clarify its biological and clinical relevance.