NEW YORK (Reuters) April 4 - Human papilloma virus (HPV) infection and periodontitis have a synergistic effect in promoting squamous cell carcinoma of the tongue, according to study findings presented Friday at the American Association for Dental Research meeting in Dallas.
"Our study is the first one to show that chronic periodontitis predicted HPV status in head and neck cancers," Dr. Mine Tezal told Reuters Health. She speculates that the chronic inflammation and bacterial infections associated with periodontitis create an environment that promotes persistent HPV infection, the strongest risk factor for carcinogenesis.
"Many studies have shown substantial evidence for HPV as a risk factor for head and neck cancers," noted Dr. Tezal, a researcher with Roswell Park Cancer Institute in Buffalo, New York. "However, HPV alone is not sufficient to cause cancer. This study suggests that chronic periodontitis may play an important role in the natural history of HPV in head and neck cancers."
The findings are based on a study of 30 patients who were diagnosed with tongue cancer at the researchers' center between 1999 and 2005.
Radiographic imaging was used to assess the degree of alveolar bone loss and, thereby, the cumulative history of periodontitis. Tumor specimens were analyzed with a PCR assay to assess the presence of DNA from HPV-16 and HPV-18, the most common HPV types seen with oropharyngeal cancers.
Nineteen of the 30 patients (63%) had HPV-16-positive tumors, the findings show. HPV-18, by contrast, was not detected in any of the specimens.
Ninety percent of patients with HPV-positive tumors had periodontitis and 79% of patients with HPV-negative tumors did not have periodontitis.
Dr. Tezal believes the new findings could have important clinical implications.
"Current treatment strategies for head and neck cancers do not address the underlying cause. They are associated with high morbidity and tumor relapse," she pointed out. "Evidence of periodontitis-HPV synergy has important practical implications since there is no treatment for HPV infection but there is a safe treatment for periodontitis."
She added that "patients with periodontitis may represent a clinical high-risk profile for HPV infection. This has tremendous relevance in prevention, early diagnosis and treatment of HPV-related diseases including head and neck cancers."
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