Preoperative oral care and effect on postoperative complications after major cancer surgery

Background: Improving patients' oral hygiene is an option for preventing postoperative pneumonia that may be caused by aspiration of oral and pharyngeal secretions. Whether preoperative oral care by a dentist can decrease postoperative complications remains controversial. A retrospective cohort study was undertaken to assess the association between preoperative oral care and postoperative complications among patients who underwent major cancer surgery. Methods: The nationwide administrative claims database in Japan was analysed. Patients were identified who underwent resection of head and neck, oesophageal, gastric, colorectal, lung or liver cancer between May 2012 and December 2015. The primary outcomes were postoperative pneumonia and all-cause mortality within 30days of surgery. Patient background was adjusted for with inverse probability of treatment weighting using propensity scoring. Results: Of 509 179 patients studied, 81 632 (16.0 per cent) received preoperative oral care from a dentist. A total of 15 724 patients (3.09 per cent) had postoperative pneumonia and 1734 (0.34 per cent) died within 30days of surgery. After adjustment for potential confounding factors, preoperative oral care by a dentist was significantly associated with a decrease in postoperative pneumonia (3.28 versus 3.76 per cent; risk difference-0.48 (95 per cent c.i. -0.64 to-0.32) per cent) and all-cause mortality within 30days of surgery (0.30 versus 0.42 per cent; risk difference - 0.12 (-0.17 to -0.07) per cent). Conclusion: Preoperative oral care by a dentist significantly reduced postoperative complications in patients who underwent cancer surgery.