Abstract 848: Pathogenic oral bacteria and risk of incident cancer in postmenopausal women: The Buffalo OsteoPerio Study
Authors: Mai Xiaodan , Genco Robert J. , LaMonte Michael J. , Hovey Kathleen M. , Freudenheim Jo L. , Andrews Christopher A. , Wactawski-Wende Jean 
Published: August 2015

Abstract
Background: Periodontal disease (PD) has been found to be associated with increased cancer risk, including among participants in the Women's Health Initiative (WHI). Microbial colonization of the subgingival area is a necessary causal factor for the development of PD. Previous findings of positive relationships between PD and cancer risk may be partially explained by extra-oral translocation of oral bacteria. We investigated the associations between the presence of three early-colonizing periodontal pathogens (Fusobacterium nucleatum, Prevotella intermedia, and Campylobacter rectus, i.e., “orange complex” bacteria moderately associated with PD), two late-colonizing periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, i.e., “red complex” bacteria strongly associated with PD) and cancer risk in a subset of the WHI.
Methods: We prospectively followed 1,252 postmenopausal women enrolled in the Buffalo OsteoPerio Study, an ancillary study of the WHI. Subgingival plaque samples were obtained during baseline oral examination from 1997 to 2000. Presence of periodontal pathogens was assessed using indirect immunofluorescence. Incident cancer cases through 2013 were identified via annual health updates and were confirmed using medical records by physician adjudicators. Cox proportional hazard regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the associations of periodontal pathogens with total and site-specific cancer risk in crude and multivariate-adjusted models (adjusting for age and smoking status).
Results: There were 171 confirmed incident cancer cases (invasive breast = 67, colorectal = 17, lung = 17) during an average follow-up of 11.8 years (SD = 3.8). When analyzed separately, individual pathogens were not associated with total or site-specific cancer. Presence of any pathogen was associated with increased lung cancer risk, although not statistically significant (adjusted HR = 3.97, 95% CI: 0.90-17.45). Presence of any late-colonizing pathogens was not statistically associated with total or site-specific cancer risks. After multivariate adjustment, there were borderline associations between presence of any early-colonizing pathogens and increased risk of total cancer (HR = 1.35, 95% CI: 1.00-1.84) and lung cancer (HR = 3.02, 95% CI: 0.98-9.29). Associations were not seen with invasive breast or colorectal cancer.
Conclusions: We did not find consistent associations between presence of subgingival periodontal pathogens and risk of several cancers, but suggestion of associations with early colonizing pathogens for total and lung cancer. These conclusions are restricted by the small numbers of events and of bacteria evaluated. To clarify the present findings, further research is needed utilizing larger cohorts and more comprehensive assessment of presence and quantity of oral bacteria.
Citation Format: Xiaodan Mai, Robert J. Genco, Michael J. LaMonte, Kathleen M. Hovey, Jo L. Freudenheim, Christopher A. Andrews, Jean Wactawski-Wende. Pathogenic oral bacteria and risk of incident cancer in postmenopausal women: The Buffalo OsteoPerio Study. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 848. doi:10.1158/1538-7445.AM2015-848