MASCC/ISOO Clinical Practice Statement: Adjuvant bone-modifying agents in primary breast cancer patients - prevention of medication-related osteonecrosis of the jaw.

PURPOSE: A MASCC/ISOO Clinical Practice Statement (CPS) is aimed at generating a concise tool for clinicians that concentrates practical information needed for the management of oral complications of cancer patients. This CPS raises awareness to the prevention of medication-related osteonecrosis of the jaw (MRONJ) in patients with breast cancer treated with adjuvant bone-modifying agents (BMA). METHODS: This CPS was developed based on a critical evaluation of the literature followed by a structured discussion of a group of leading experts, members of the Oral Care Study Group of MASCC/ISOO. The information is presented in the form of succinct bullets and tables to generate a short manual about the best standard of care. RESULTS: In patients treated with adjuvant BMA, dento-alveolar surgery poses a moderate risk for MRONJ that ranges between the high risk for MRONJ in patients with metastatic breast cancer and the low risk for MRONJ in patients with osteoporosis. Existing MRONJ guidelines serve as a starting point for adjuvant BMA use. Urgent procedures should be delivered without delay using the accepted precautions to prevent MRONJ. If elective surgery is considered, the individual risk for MRONJ following surgery should be assessed according to common risk factors. CONCLUSION: Prevention of MRONJ in primary breast cancer patients treated with adjuvant BMA requires risk-benefit assessment; collaboration between the medical team, dental professional, and patient; and patient-specific tailored dental treatment planning. The patient should be informed about this risk. Additional research is needed to define optimal MRONJ care for this population.

Effect of tranexamic acid on blood loss reduction in patients undergoing orthognathic surgery under hypotensive anesthesia: a single-center, retrospective, observational study.

Objectives: Orthognathic surgery is a surgical procedure performed by intraoral approach with established and safe techniques; however, excessive blood loss has been reported in rare cases. In response, investigative efforts to identify methods to reduce the amount of blood loss have been made. Among such methods, the administration of tranexamic acid was reported to reduce the amount of intraoperative blood loss. However, few studies to date have reported the effect of tranexamic acid in orthognathic surgery under hypotensive anesthesia. The present study aimed to investigate the effect of the administration of tranexamic acid on intraoperative blood loss in patients undergoing bimaxillary (maxillary and mandibular) orthognathic surgery under hypotensive anesthesia. Patients andMethods: A total of 156 patients (mean age, 27.0±10.8 years) who underwent bimaxillary orthognathic surgery under hypotensive anesthesia performed by the same surgeon between June 2013 and February 2022 were included in this study. The following data were collected from the medical records of each patient: background factors (age, sex, and body mass index), use of tranexamic acid, surgical procedures, previous medical history, duration of surgery, American Society of Anesthesiology physical status findings before surgery, intraoperative blood loss as a primary outcome, in-out balance, and blood test results. Descriptive statistics were calculated for statistical analysis, and a t -test and the chi-squared test were used for between-group comparisons. Group comparisons were performed after 1:1 propensity score matching to adjust for confounding factors. Statistical significance was set at P<0.05. Results: Comparison between the groups based on the use of tranexamic acid revealed a significant difference in operation time. Propensity score matching analysis revealed that intraoperative blood loss was significantly lower in the tranexamic acid group. Conclusion: The administration of tranexamic acid was effective in reducing intraoperative blood loss in patients undergoing bimaxillary orthognathic surgery under hypotensive anesthesia.

[A Case of Severe Skin Disorder during Pembrolizumab Treatment for Recurrent Maxillary Gingival Carcinoma].

Immune checkpoint inhibitors are known to produce immune-related adverse events(irAE)that require medical management. Herein, we report a case of a patient treated with pembrolizumab who experienced a Grade 3 interrupted skin disorder. The patient is a 67-year-old female diagnosed with right maxillary gingival squamous cell carcinoma(cT4aN0M0, Stage ⅣA)and underwent partial right maxillectomy, right extended supra-omohyoid neck dissection, and maxillary reconstruction using a forearm flap. Six months postoperatively, late lymph node metastases with extracapsular spread was found in the right buccal lymph node and the left neck, and the patient underwent right buccal lymphadenectomy and left modified radical neck dissection. After postoperative combined chemoradiotherapy(cisplatin plus IMRT)followed by 13 courses of cetuximab plus paclitaxel, a recurrent lesion was found in the right buccal region. After 8 courses of pembrolizumab, a skin rash appeared on the forearm, chest, and back, which was diagnosed as Grade 3 irAE, requiring hospitalization. The patient was re-instituted after waiting for improvement of the skin disorder. The pembrolizumab at 75% reduction dose was re-administrated, and the patient has been followed up so far.

Nurses' Awareness of and Current Approaches to Oral Care in a Community Hospital in Japan: A Longitudinal Study of Dental Specialists' Interventions.

Objective: This study aimed to increase nurses' interest and priority in oral care by implementing educational interventions, such as teaching oral care methods suitable for each patient in clinical settings, over a period of one year. Materials and Methods: This study included all 150 nurses working in Unnan City Hospital in Japan who answered a questionnaire comprising 19 questions regarding awareness, actual implementation status of oral care provided, burden, and involvement with oral and maxillofacial surgery department of the hospital, along with participants' characteristics. The rate of interest in learning, need for oral care, time spent in oral care, and oral health-related caregiver burden index (OHBI) score were compared between pre- and post-intervention groups. Results: The number and rate of valid questionnaires were 136 and 90.7%, respectively. The mean years of clinical experience were 19.3 ± 12.5 years; 93.4% of the nurses were women. After the interventions by dental specialists, the nurses' level of interest in and priority to oral care were significantly higher than those before the interventions (p < 0.001), regardless of nurses' background, such as age, gender, or years of experience. However, the "burden" did not statistically decrease. Conclusions: This study shows that dental specialists succeeded in significantly increasing nurses' interest in and priority to oral care by intervening in clinical practice but failed in decreasing nurses' burden of oral care. In the future, we would like to investigate the problems that hinder the reduction of the sense of burden, reduce the burden of nurses' oral care, and improve oral care.

A rare case of dentinogenic ghost cell tumor with concomitant odontoma.

Key Clinical Message: A case of dentinogenic ghost cell tumor occurring simultaneously with a clinically diagnosed odontoma. The occurrence of epithelial and mesenchymal tumors at the same site is very rare, but should be kept in mind during pathological diagnosis. Abstract: Dentinogenic ghost cell tumor (DGCT) is a rare and benign odontogenic tumor composed of ghost cells, calcified tissue, and dentin. We present an extremely rare case of a 32-year-old female who was clinically diagnosed with an odontoma presenting with a painless swelling in her maxilla. Radiographic examination showed a well-defined radiolucent lesion with tooth-like calcified areas. The tumor was resected under general anesthesia. No recurrence was noted at the 12-month follow-up. Histopathological examination of the surgically resected tumor yielded a diagnosis of DGCT with odontoma.

Postoperative Complications following Open Reduction and Rigid Internal Fixation of Mandibular Condylar Fracture Using the High Perimandibular Approach.

The high perimandibular approach is a feasible surgical technique for treating mandibular condylar fractures with open reduction and internal fixation, followed by fewer complications. Temporary trismus is the only postoperative complication that may occur. This study evaluated postoperative complications following open reduction and rigid internal fixation (OR-IF) of mandibular condylar fractures using the high perimandibular approach. Twenty consecutive patients undergoing OR-IF were included in this study. They included 11 male and 9 female patients, of an average age of 58.5 years, all of whom responded to a follow-up call at least 12 months after the surgery. All patients were evaluated for range of mouth opening, postoperative complications, and radiological findings. A statistical analysis of the relationship between range of mouth opening and related clinical parameters at 6 months postoperative evaluation was conducted. The fracture of the condylar neck was associated with a limited range of mouth opening and longer operation time. However, longer operation time was not associated with a limited range of mouth opening. The high perimandibular approach with OR-IF in mandibular condylar fractures is a feasible and safe technique; however, prolonged surgery and mandibular condylar neck fractures could affect the postoperative range of mouth opening.

Oral Dysfunction in Patients with Oral Cancer Could Occur Before Treatment and Require Early Nutritional Improvement: A Cross-Sectional Study.

Patients with oral cancer have poor nutritional status before treatment. However, there have been no reports of the detailed evaluation of preoperative oral function in patients with oral squamous cell carcinoma (OSCC). Therefore, this study aimed to evaluate the preoperative oral function of patients with OSCC and examine the relationship with nutritional status. Oral function measurements (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function, Eating Assessment Tool, and Postoperative Oral Dysfunction Scale) and Mini Nutritional Assessment-Short Form (MNA-SF) data were collected from 51 patients with OSCC (men: 37, women: 14, mean age: 72.1 years) who visited the Shimane University Hospital, Department of Oral and Maxillofacial Surgery, from September 2019 to September 2021. The tongue was the most prevalent primary gingiva site [22 patients (43.1%)], and 36 patients (70.6%) had advanced cancer. Comparisons between nutritional status and each related factor revealed significant differences in the number of individuals in the household, cancer stage, presence of pulmonary disease, number of teeth, microorganisms (grade), and masticatory function (mg/dL) (p < 0.05). Multiple regression analysis using the total MNA-SF score as the dependent variable with adjustment for confounding factors showed significant association between oral dryness and tongue pressure (p < 0.05). No significant association was found for the Eating Assessment Tool or Postoperative Oral Dysfunction scale. Patients with OSCC may have decreased oral function because of the tumor at the time of diagnosis, which causes a decline in nutritional status. Preoperative interventions are necessary to improve nutrition based on the state of oral function.

[Effect of the Hyoid Bone Suspension Technique on the Preservation of Swallowing Function after Total Glossectomy and Pectoralis Major Musculocutaneous Flap Reconstruction for Locally Advanced Tongue Cancer].

Dysphagia is a major postoperative complication in patients with locally advanced oral cancer. In this case report, we describe the effect of the hyoid bone suspension technique on the preservation of swallowing function after total glossectomy and pectoralis major musculocutaneous flap reconstruction for locally advanced tongue cancer. Case: A 72-year-old Japanese male was diagnosed with advanced squamous cell carcinoma on the left side of his tongue(cT4aN2cM0, cStage ⅣA). Under general anesthesia, the patient underwent a tracheotomy, bilateral modified radical neck dissection type Ⅲ, total glossectomy, and reconstruction with a left pectoralis major musculocutaneous flap(PMMC flap). Intraoperatively, the PMMC flap was designed to have a heart shape of 11×6 cm and was elevated. Subsequently, holes were made at the lower edge of the mandible, and the hyoid bone was suspended and fixed to the mandibular border using 2-0 nylon sutures. The postoperative course was uneventful; the flap was completely engrafted and was in good condition. The hyoid bone suspension technique can reproduce the pharyngeal phase of swallowing, and the palatal augmentation prosthesis helps to improve food mass feeding and preserve the swallowing function.

Oral functional impairment may cause malnutrition following oral cancer treatment in a single-center cross-sectional study.

Oral dysfunction and dysphagia after oral cancer treatment are linked to altered nutritional status. We aimed to identify specific oral functions related to nutritional status. We conducted a cross-sectional study from September 2019 to December 2021, recruited 75 participants (median age: 72.0 years), including 52 males and 23 females, collected background data, and evaluated oral function. The Mini Nutritional Assessment-Short Form (MNA-SF) scores were divided into three groups (normal nutritional status, at risk of malnutrition, and malnourished), and a multi-group comparison was conducted for each oral function measurement (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function, and Eating Assessment Tool [EAT-10]). The primary tumor site was the tongue in 31 patients (41.3%), gingiva in 30 (40.0%), and others in 14 (18.7%). Multiple comparisons revealed significant differences in occlusal force, tongue pressure, masticatory function, and EAT-10 levels, categorized as Type I (Transport type) and Type III (Occlusion type) postoperative oral dysfunctions, between each MNA-SF group. Multiple regression analysis showed a statistically significant association with MNA-SF in terms of masticatory function and EAT-10 levels, categorized as Type I. Type I and Type III are risk factors for malnutrition, confirming that different types of postoperative oral dysfunction require unique nutritional guidance.

MASCC/ISOO expert opinion on the management of oral problems in patients with advanced cancer.

PURPOSE: The Palliative Care Study Group in conjunction with the Oral Care Study Group of the Multinational Association for Supportive Care in Cancer (MASCC) formed a sub-group to develop evidence-based guidance on the management of common oral problems in patients with advanced cancer. METHODS: This guidance was developed in accordance with the MASCC Guidelines Policy. A search strategy for Medline was developed, and the Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials were explored for relevant reviews and trials, respectively. Guidance was categorised by the level of evidence, and "category of guideline" (i.e., "recommendation", "suggestion" or "no guideline possible"). RESULTS: Twelve generic suggestions (level of evidence - 5), three problem-specific recommendations and 14 problem-specific suggestions were generated. The generic suggestions relate to oral hygiene measures, assessment of problems, principles of management, re-assessment of problems and the role of dental/oral medicine professionals. CONCLUSIONS: This guidance provides a framework for the management of common oral problems in patients with advanced cancer, although every patient requires individualised management.

Oral Health Management and Rehabilitation for Patients with Oral Cancer: A Narrative Review.

Surgery is the current first choice for oral cancer treatment. Intensity-modulated radiation therapy, molecular targeted drugs, and immune checkpoint inhibitors are still used as adjuvant therapy for advanced cancer. In addition, postoperative rehabilitation and multidisciplinary treatment have also been developed in recent years. Multidisciplinary team approaches and supportive care in oral cancer treatment reportedly shorten the time to treatment and improve outcomes. Although there is enough evidence confirming the role of oral and maxillofacial surgeons, dentists, and dental hygienists in supportive care in oral cancer treatment, there are very few systematic studies. In particular, oral health management is a concept that encompasses oral function management, oral hygiene management, and oral care during oral cancer treatment. We provide a narrative review focusing on oral health management from a multidisciplinary and supportive care perspective, applicable in oral cancer treatment.

Discrepancy between subjective and objective postoperative oral dysfunction assessment after oral cancer treatment: A single-center cross-sectional study.

OBJECTIVES: It has been reported that in many cancer types, the evaluation of complications and side effects of treatment differs between subjective and objective evaluations. The purpose of this study is to verify whether the evaluation of postoperative oral dysfunction following oral cancer treatment was consistent subjective and objective evaluations. MATERIALS AND METHODS: This cross-sectional study collected background data and evaluated the oral function (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function and eating assessment tool [EAT-10]) of 75 patients from September 2019 to December 2021. The postoperative oral dysfunction-10 (POD-10) was used for the subjective assessment of dysfunction in oral cancer patients. Also, Matsuda-Kanno classification was used for the objective assessment. The kappa coefficient between POD-10 and oral dysfunction was calculated for the degree of agreement. The relationship between oral function measurements and POD-10 was examined by multiple regression analysis. RESULTS: The patients' median age was 72.0 (25-75 percentile: 64.0-78.0) and 69.3% were male. The kappa coefficients indicating the degree of agreement with POD-10 were 0.41 (P < 0.01) for occlusal force, 0.27 (P = 0.01) for masticatory function, and 0.59 (P < 0.01) for EAT-10. Multiple regression analysis showed a significant association of occlusal force (ß = -0.33, P = 0.03) and EAT-10 (ß = 0.80, P < 0.01) with POD-10. CONCLUSIONS: For postoperative oral dysfunction type III (occlusal type), the evaluations of subjective and objective evaluations tended to be consistent. However, for type I (transport type) and II (oral hygiene type), these evaluations may be prone to overestimation or underestimation by either the medical professional or the patient.

Development of a Subjective Symptom Rating Scale for Postoperative Oral Dysfunction in Patients with Oral Cancer: Reliability and Validity of the Postoperative Oral Dysfunction Scale-10.

Currently, there is no scale to subjectively assess postoperative oral dysfunction in patients with oral cancer. The purpose of this study was to evaluate the reliability and validity of the Postoperative Oral Dysfunction Scale (POD-10) that we developed. Between September 2019 and August 2021, 62 eligible oral cancer patients (median age, 72 years; 42 men and 20 women) were enrolled in the study. The Cronbach's alpha coefficient, which indicates the internal consistency of the scale, was 0.94, and the intraclass correlation coefficient, which indicates reproducibility, was 0.85 (95% confidential interval: 0.40-0.96, p < 0.05). Concurrent validity testing showed a statistically significant correlation between POD-10 and Eating Assessment Tool (EAT-10) (r = 0.89, p < 0.05). To test discriminant validity, statistically significant differences were found between early-stage cancer (stage I and II) and advanced-stage cancer (stage III and IV) (p < 0.05). Twenty-four points were calculated as the cutoff value for POD-10 using receiver operating characteristic analysis to calculate the cutoff value. The POD-10 was shown to be a clinically reliable and valid scale that can be used to subjectively assess postoperative oral dysfunction in patients with oral cancer and is expected to be used as a simple diagnostic tool.

Relationship between Oral Bacterial Count and Postoperative Complications among Patients with Cardiovascular Disease Treated by Surgery: A Retrospective Cohort Study.

In this retrospective observational study, we evaluated the relationship between perioperative oral bacterial counts and postoperative complications in cardiovascular disease (CVD) patients. From April 2012 to December 2018, all patients scheduled for surgery received perioperative oral management (POM) by oral specialists at a single center. Tongue dorsum bacterial counts were measured on the pre-hospitalization day, preoperatively, and postoperatively. Background data were collected retrospectively. Among the 470 consecutive patients, the postoperative complication incidence rate was 10.4% (pericardial fluid storage, n = 21; postoperative pneumonia, n = 13; surgical site infection, n = 9; mediastinitis, n = 2; and seroma, postoperative infective endocarditis, lung torsion, and pericardial effusion, n = 1 each). Oral bacterial counts were significantly higher in the pre-hospitalization than in the pre- and postoperative samples (p < 0.05). Sex, cerebrovascular disease, and operation time differed significantly between complications and no-complications groups (p < 0.05). Multivariate analysis with propensity score adjustment showed a significant association between postoperative oral bacterial count and postoperative complications (odds ratio 1.26; 95% confidence interval, 1.00-1.60; p = 0.05). Since the development of cardiovascular complications is a multifactorial process, the present study cannot show that POM reduces complications but indicates POM may prevent complications in CVD patients.

Postoperative oral dysfunction following oral cancer resection and reconstruction: A preliminary cross-sectional study.

OBJECTIVES: Oral cancer treatment reportedly causes decreased oral function, but few studies have examined the effects of oral cancer treatment on oral function in depth. This study aimed to comprehensively evaluate the oral function after treatment and classify the conditions related to oral dysfunction in patients with oral cancer. MATERIALS AND METHODS: We recruited participants, collected their background data, and evaluated their oral function from September 2019 to March 2021. Principal component analysis was used to identify the components of oral function measurement and oral health perception. Receiver operating characteristic analysis was performed to investigate the accuracy of oral function measurements in predicting oral intake and nutritional status. RESULTS: Fifty patients treated for oral cancer, including 33 (66.0%) males and 17 (34.0%) females, were included. Their median age was 71.0 years (interquartile range: 63.0-76.0). There were significant differences in oral dryness between males and females, occlusal force among different age groups, tongue pressure based on the tumor stage and performance of reconstructive procedures, and masticatory function and Eating Assessment Tool scores based on whether radiotherapy was performed (P < 0.05). The principal component analysis proposed that oral function measurements and subjective oral health perception could be divided into three main components (transport, oral hygiene, and occlusion type), which explain 61.5% of the variance of the phenomenon. CONCLUSION: A significant decrease in oral function after oral cancer treatment should be diagnosed as postoperative oral dysfunction. Postoperative oral dysfunction can be classified into three types, each of which may present with different pathologies.

Complications of Poly-l-Lactic Acid and Polyglycolic Acid (PLLA/PGA) Osteosynthesis Systems for Maxillofacial Surgery: A Retrospective Clinical Investigation.

Two second-generation PLLA/PGA bioresorbable osteosynthetic plate systems for oral and maxillofacial surgery are available in Japan. The two systems have different PLLA-PGA component ratios (RapidSorb®, 85:15; Lactosorb®, 82:18) and plate and screw shapes. We conducted a retrospective study to compare our clinical evaluation and examine the incidence of postoperative complications between the two plate systems. A retrospective survey was conducted in 148 patients (midfacial fracture/trauma (68.2%) and dentofacial deformity patients (31.8%); males (54.7%); median age, 37.5 years) treated using maxillofacial osteosynthetic plate systems. The complications included plate exposure (7.4%), infection, (2.7%), and plate breakage (0.7%). Multivariate logistic regression analysis showed a significant correlation between sex (female), plate system (Lactosorb®), number of plates, and pyriform aperture and periorbital sites of plate placement (p < 0.05). Additionally, the propensity score-adjusted model showed a significant correlation between Lactosorb® and postoperative complications (odds ratio 1.007 (95% confidence interval, 1.001-1.055), p < 0.01). However, the two plate systems showed a low incidence rate of complications, and the plate integration and survivability were similar using 2.0-mm or 1.5-mm resorbable plate regardless of the plate system. Our findings suggest that female sex and a greater number of plates are risk factors for postoperative complications, whereas pyriform aperture and periorbital plate placements reduce the risk.

Development and Validation of the Oral Health-Related Self-Efficacy Scale for Cancer Patients.

This study aimed to validate the Oral Health-related Self-Efficacy Scale for Patients with Cancer (OSEC), comprised of 17 questions (five factors). To this end, a sample of 203 cancer patients was recruited (August 2018-April 2019) followed by a random subsampling for test-retest reliability. Concurrent validity was tested by correlating scores with the Self-efficacy Scale for Advanced Cancer (SEAC), discriminant validity was tested by comparing high OSEC to low OSEC groups, and predictive validity was tested using a plaque control record. Five OSEC factors had Cronbach's alpha coefficients ranging from 0.75 to 0.88. The intraclass correlation coefficient of the total score was 0.92 upon test-retest reliability. The factor-level scores significantly related to all the SEAC factor-level scores. The differences between the high OSEC and low OSEC groups were statistically significant in the total score and on all factor-level scores (p < 0.01). The plaque control record of the high OSEC group was significantly lower than that of the low OSEC group (p < 0.01). In conclusion, the OSEC can be used for understanding cancer patients' motives for oral care behaviors and applied to program planning to increase self-efficacy and health behaviors.

[Mass Screening of Oral Cancer in Eastern Shimane Prefecture during 2015-2019].

The Department of Oral and Maxillofacial Surgery, Shimane University Faculty of Medicine, has been conducting mass screening of oral cancer using oral abrasion cytology by oral surgeons in eastern Shimane prefecture for public awareness and its early detection. As a result, 3(0.09%)cases of oral cancer were identified. Case 1: The patient was diagnosed with well-differentiated squamous cell carcinoma in the floor of the mouth(pT1N0M0, Stage Ⅰ)after undergoing Matsue city oral cancer screening in 2016. Case 2: The patient underwent oral cancer screening in Izumo city in 2018 and was diagnosed with verrucous carcinoma in the back of the tongue(pT1N0M0, Stage Ⅰ). Case 3: The patient was diagnosed with highly differentiated squamous cell carcinoma of the palate(pT1N0M0, Stage Ⅰ)after undergoing the Izumo city oral cancer screening in 2019. Awareness of oral cancer is important, and cancer screening by oral surgeons using cytology is highly useful and should be continued in the future.

[A Case of Treatment Applicable to Squamous Cell Carcinoma of the Tongue by Mass Screening Examination of Oral Cancer in Western Part of the Shimane Prefecture].

Radical excision, a common oral cancer treatment, produces variable postoperative results depending on the specialized tissues involved and the extent of the cancer. Furthermore, the material selected for reconstruction also influences functional outcomes. Oral dysfunction due to postoperative tissue loss is more common with advanced cancer; therefore, early detection and treatment are important. To improve oral cancer awareness and early detection, mass oral cancer screenings led by maxillofacial surgeons in cooperation with the Shimane prefecture and local dental associations were conducted. We describe the mass screening methods and describe a case of tongue cancer that was detected and treated as a result of our screening efforts.

Relationship between Oral Health Status and Postoperative Fever among Patients with Lung Cancer Treated by Surgery: A Retrospective Cohort Study.

A retrospective observational study using an oral bacteria counter was conducted to evaluate the trends in the number of oral bacteria in the perioperative period of lung cancer patients and to verify the relationship between oral health status and postoperative fever. All patients received perioperative oral management (POM) by oral specialists between April 2012 and December 2018 at Kagawa Prefectural Central Hospital, Kagawa, Japan prior to lung cancer surgery. Bacteria counts from the dorsum of the tongue were measured on the day of pre-hospitalization, pre-operation, and post-operation, and background data were also collected retrospectively. In total, 441 consecutive patients were enrolled in the study. Bonferroni's multiple comparison test showed significantly higher oral bacteria counts at pre-hospitalization compared to pre- and post-operation (p < 0.001). Logistic regression analysis showed that body mass index, performance status, number of housemates, number of teeth, and white blood cell count at pre-operation were significantly associated with postoperative fever. The study showed that POM can reduce the level of oral bacterial counts, that the risk of postoperative complications is lower with dentulous patients, and that appropriate POM is essential for prevent of complications. Therefore, POM may play an important role in perioperative management of lung cancer patients.