The impact of chemotherapeutic treatment on the oral microbiota of patients with cancer: a systematic review

Objective: Chemotherapy is a type of systemic treatment that inhibits neoplastic cells (cancer cells), produces immunosuppression, and may lead to changes in the oral mucosa and, consequently, in the oral microbiota. The aim of this systematic review was to analyze, in the scientific literature, evidence of the impact of chemotherapy on the oral microbiota. Study Design: The authors conducted a search in PubMed/MEDLINE, Scientific Electronic Library Online (SciELO), LILACS, ScienceDirect, Web of Science, and Cochrane Library; to identify studies that discussed change in the oral microbiota of patients with during chemotherapy. Articles published in English until July 2017 were included. The quality of a study was assessed by using the Ottawa-Newcastle scale. Results: Of 5252 articles potentially relevant to this review, 17 were included in this study. Of the 17 studies included, 16 had used culture techniques, and 1 had used genetic sequencing. The most frequently observed bacteria were aerobic gram-negative (Klebsiella spp., Escherichia coli, Enterobacter, Pseudomonas spp.), anaerobic gram-negative (Veillonella spp., Capnocytophaga), and gram-positive bacteria (Streptococcus spp., Staphylococcus spp.). Conclusions: During chemotherapy, patients with cancer present a more complex oral microbiota under favorable conditions for their development during immunosuppression, and these may be responsible for different serious local or systemic pathologies.