Abstract A37: Restoration of oral microbiota dysbiosis in head and neck squamous cell carcinoma after surgery

Introduction: Increasing reports have indicated the association between oral microbiota dysbiosis and HNSCC, while it is unclear how the oral microbiota responds to surgery. In this study, we longitudinally collected oral rinse samples from patients with HNSCC right before and after surgery at 1, 3, and 6 months, in order to elucidate the dynamic changes of oral microbiota upon treatment. Materials and Methods: A total of 91 HNSCC patients were recruited, with 20 having been collected for a longitudinal set of samples for 6 months. Meanwhile, 93 healthy subjects were selected as controls. The microbiota from oral rinses was classified by 16S rRNA gene V3-V4 amplicon sequencing and QIIME2 algorithm. Results: Although there was no obvious difference in the alpha- and beta-diversities of oral microbiota between HNSCC patients and healthy subjects, we observed a number of bacterial genera significantly discriminating cases from controls. Further analysis of oral microbiota in HNSCC between pre- and post-surgery found that the community diversity was dramatically depressed at 1 month after surgery (p=0.001), but this was able to restore to the normal level from 3 months with no significant difference between 3 months and preop (p>0.05). The relative abundance of the commensal bacteria, including Streptococcus, Rothia, Corynebacterium, and Granulicatella, consistently increased along 1-, 3-, and 6-month recovery, while the periodontal pathogens Fusobacterium and Peptostreptococcus decreased. Conclusions: The findings indicate that a taxonomically defined microbial consortium is associated with HNSCC and the oral microbiota is able to restore to the community, trending to healthy status after surgery. Citation Format: Jason Y.K. Chan, Bowie Wong, Eddy W.Y. Wong, Paul Chan, Zigui Chen. Restoration of oral microbiota dysbiosis in head and neck squamous cell carcinoma after surgery [abstract]. In: Proceedings of the AACR Special Conference on the Microbiome, Viruses, and Cancer; 2020 Feb 21-24; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2020;80(8 Suppl):Abstract nr A37.