Certain oral bacteria linked to higher risk for esophageal cancer
Oral bacteria appeared to be more abundant in patients with esophageal cancer compared with otherwise healthy controls, according to results of a study published in Cancer.
Researchers also found that prevalence of three of these bacteria, as well as drinking habit, appeared to be associated with high risk for esophageal cancer.
“In recent years, many epidemiological studies have reported a potential connection between periodontitis and increased risk for gastrointestinal cancers,” Machiko Kawasaki, DDS, researcher in the department of clinical oncology at the Graduate School of Medical and Dental Sciences at Tokyo Medical and Dental University in Japan, and colleagues wrote. “Moreover, the DNA of certain oral bacteria, including Porphyromonas gingivalis and Streptococcus anginosus, was frequently detected in samples of esophageal cancer tissues. In addition, several studies have suggested that various pathogenic bacteria are enriched in the saliva of patients with esophageal cancer. However, the association between periodontal disease and esophageal cancer is still controversial and the underlying mechanisms remain unclear.”
For this reason, researchers compared oral microbiota characteristics of 61 patients (n = 47 men) with esophageal cancer and 62 matched controls (n = 50 men) without cancer who were hospitalized in Tokyo between 2018 to 2020. They collected samples of subgingival dental plaque and unstimulated saliva and used a real-time polymerase chain reaction assay to evaluate the prevalence and abundance of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, P. gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola and S. anginosus.
Results showed periodontal probing depth (P = .02), bleeding on probing (P = .01), smoking history rate (P = .003) and drinking habit rate (P < 10–7) were all significantly increased among those with esophageal cancer, whereas BMI was significantly higher among otherwise healthy controls (P = .003).
Overall, 15 patients had stage I esophageal cancer, 12 patients had stage II disease, 21 patients had stage III disease, nine had stage IVA disease and four patients had stage IVB disease. Moreover, 58 patients had squamous cell carcinoma and three had adenocarcinoma.
Except for F. nucleatum, the prevalence of oral bacteria was significantly higher in the esophageal cancer group compared with controls, including A. actinomycetemcomitans (P < 10–3), P. intermedia (P = .002), P. gingivalis (P = .04), S. anginosus (P < 10–7), T. denticola (P < 10–4) and T. forsythia (P < 10–7).
Researchers detected A. actinomycetemcomitans in 16 patients with esophageal cancer compared with only two controls.
When the researchers analyzed each bacterium as a percentage of the number of total bacteria, they observed significantly higher percentages of A. actinomycetemcomitans (P < 10–3), P. gingivalis (P = .02), S. anginosus (P = .02), T. denticola (P = .003) and T. forsythia (P < 10–3) ] in patients with esophageal cancer vs. controls.
Results of a logistic regression analysis showed associations between higher risk for esophageal cancer and prevalence of T. forsythia (OR = 7.9; 95% CI, 2.2-28.5) and S. anginosus (OR = 32.8; 95% CI, 3.25-331) in dental plaque, A. actinomycetemcomitans (OR = 5.77; 95% CI, 1.62-25.4) in saliva, and drinking habit (OR = 17.1; 95% CI, 3.95-74-3), according to the researchers.
“The current study sheds light on the positive relation between esophageal cancer and the specific oral bacteria present in dental plaque and saliva,” they wrote. “These findings suggest the diagnostic potential of oral bacteria in the context of esophageal cancer.”