CD155 on Tumor Cells Drives Resistance to Immunotherapy by Inducing the Degradation of the Activating Receptor CD226 in CD8+ T Cells.

The activating receptor CD226 is expressed on lymphocytes, monocytes, and platelets and promotes anti-tumor immunity in pre-clinical models. Here, we examined the role of CD226 in the function of tumor-infiltrating lymphocytes (TILs) and resistance to immunotherapy. In murine tumors, a large proportion of CD8+ TILs had decreased surface expression of CD226 and exhibited features of dysfunction, whereas CD226hi TILs were highly functional. This correlation was seen also in TILs isolated from HNSCC patients. Mutation of CD226 at tyrosine 319 (Y319) led to increased CD226 surface expression, enhanced anti-tumor immunity and improved efficacy of immune checkpoint blockade (ICB). Mechanistically, tumor-derived CD155, the ligand for CD226, initiated phosphorylation of Y319 by Src kinases, thereby enabling ubiquitination of CD226 by CBL-B, internalization, and proteasomal degradation. In pre-treatment samples from melanoma patients, CD226+CD8+ T cells correlated with improved progression-free survival following ICB. Our findings argue for the development of therapies aimed at maintaining the expression of CD226.

Surgical Resection and Reconstruction of Ameloblastoma: A 13-Year Retrospective Review.

BACKGROUND: Ameloblastoma is a locally aggressive, benign tumor presenting in the maxilla and mandible prone to recurrence. Resection greatly limits recurrence; however, reconstruction becomes critical to preserve patients' functionality and esthetics. PURPOSE: The aim of this study was to describe surgical resection and reconstructive approaches in the treatment of ameloblastoma and compare clinical outcomes to conservative methods of treatment. STUDY DESIGN, SETTING, SAMPLE: A retrospective case series was completed through analysis of patient records. The study population was composed of patients treated for ameloblastoma at the Royal Brisbane Hospital (Queensland, Australia) in the Oral and Maxillofacial Surgery Unit from January 1, 2008, to December 31, 2020. Patients without histological confirmation of intraosseous ameloblastoma were excluded from the study sample. PREDICTOR VARIABLE: Not applicable. MAIN OUTCOME VARIABLE(S): The primary outcome variable was time to recurrence. Secondary outcome variables included any surgical complications incurred. COVARIATES: The covariate variables collected included age at diagnosis/treatment, gender, ethnicity, location of lesion and site(s) of involvement, tumor extent, alveolar expansion, histopathological growth pattern, and soft tissue involvement. ANALYSES: Descriptive statistics were computed for each study variable. RESULTS: A total of 48 cases of histologically confirmed ameloblastoma were identified (41 mandibular, 7 maxillary) involving 50 excisional operations (44 resections, 6 enucleations). Of these cases, 44 were followed up > 12 months, with a mean length of follow-up time of 65.6 months. No recurrence was detected for resected lesions. One enucleated lesion recurred at 25 months. Thirty-seven reconstructive procedures were undertaken, including 32 immediate free flaps. All reconstructive flaps and grafts survived, and no major complications were recorded. CONCLUSION AND RELEVANCE: Resection of ameloblastoma limits recurrence and should be considered curative. Immediate microvascular free flap reconstruction of maxillary and mandibular defects from resection of ameloblastoma is safe and predictable.

Do Post-injury Prophylactic Antibiotics Reduce Infection for Isolated Midface Fractures: A Cohort Study.

PURPOSE: Fractures of the midface are a core component to the practice of contemporary oral and maxillofacial trainees and surgeons. As such, in an era where antibiotic resistance is increasing it is important to investigate if antibiotics are required after midface fractures to prevent infections before follow-up in an outpatient setting. The purpose of this study is to determine whether postinjury prophylactic preoperative antibiotics reduce rates of infection after midface fracture. METHODS: A retrospective multicenter cohort study was conducted in Queensland, Australia. Patients who presented to Royal Brisbane Hospital and Townsville Hospital with isolated midface fractures between January 2017 and January 2019 were included. Clinical and demographic data of patients who received postinjury prophylactic antibiotics were compared to those who did not using the χ2 test. Logistic regression was used to determine factors associated with increased odds of postinjury prophylactic antibiotic prescription. RESULTS: In total, 1,353 patients with midfacial fractures over the 2-year period were included. In addition, 724 (53.5%) patients received postinjury antibiotics and 629 (46.5%) patients did not. The overall rate of infection was very low: 1 patient who received postinjury prophylactic antibiotics (0.1%) developed infection compared to 2 patients (0.3%) who did not receive postinjury prophylactic antibiotics, and this difference was not significant (χ2 = 0.49; P = .48). Male sex (odds ratio 1.4; 95% confidence interval, 1.1 to 1.7; P = .02) and tobacco use (odds ratio 1.4; 95% confidence interval, 1.1 to 1.7; P = .008) were associated with an increased odds of postinjury prophylactic antibiotic prescription in the univariate analyses, but were no longer significant once site, age, and fracture type were adjusted for in the multivariate model. CONCLUSIONS: The rate of infection after midface fracture was low and there was no significant difference in infection rates for patients who received postinjury prophylactic antibiotics compared to those who did not. Use of postinjury prophylactic preoperative antibiotics for midfacial fractures should be reconsidered.

Osseointegrated implant survival, success and prosthodontic outcomes in composite free flaps: A 10-year retrospective cohort study.

OBJECTIVES: To evaluate implant survival, success and prosthodontic outcomes in a variety of composite free flaps. MATERIAL AND METHODS: A retrospective analysis of patient records was used for data collection of implants placed into flaps. Free flap donor sites included fibula, iliac crest, scapula, medial femoral condyle and radial forearm. Kaplan-Meier survival curves were used to estimate survival. Cox regression was used to assess variables affecting survival, and binary logistic regression was utilised to determine effect of variables on prosthodontic outcomes. RESULTS: There were 150 implants placed into 45 fibula, 98 implants into 29 iliac crest, 62 implants into 22 scapula, 6 implants into 3 medial femoral condyle and 2 implants in radial forearm composite free flaps. There was no difference in survival or success between or within the various flaps. Active smoking, increasing age, male gender and radiotherapy were associated with implant failure. Of patients completing prosthodontic rehabilitation, 93% were successful. There was no difference in likelihood of failure between different flap types. Fixed implant-supported dentures were associated with poor oral hygiene compared with removable designs (OR2.9, 95%CI 1.1-7.8, p = .03). CONCLUSIONS: There is adequate survival and success of implants in common flaps. Caution is required when planning implants in patients exposed to radiotherapy and smokers. Ability to maintain adequate oral hygiene is an important prosthetic design consideration.

Missed opportunities for oral cancer screening in Australia.

OBJECTIVES: Most patients with oral cancer lack early symptoms, therefore most present with advanced stage of disease. Early detection of oral cancer and oral potentially malignant disorders (OPMDs) in the asymptomatic phase via an opportunistic oral cancer screening examination is important as survival rates are significantly improved if the disease is treated at an earlier stage. The objective is to identify opportunities to achieve early stage diagnosis of oral cancer in Australian patients. MATERIALS AND METHODS: A cohort of 103 patients newly diagnosed with oral cancer were surveyed at a tertiary hospital Head and Neck Clinic. Patient awareness, knowledge, risk factors and diagnostic delay in oral cancer diagnosis were investigated. The asymptomatic period before diagnosis was studied to identify opportunities for improving opportunistic screening rates in Australia. RESULTS: Australian patients have poor awareness of oral cancer with 46% having never heard of oral cancer, and poor knowledge of risk factors for oral cancer. Only 7% were diagnosed in the asymptomatic phase and all by dental practitioners. Once symptomatic, median diagnostic delay was 9 weeks. In the asymptomatic phase before diagnosis, patients attended general medical practitioners far more often than general dental practitioners. Both groups rarely discussed risk factors for oral cancer (<10%) or performed opportunistic oral cancer screening examinations (<10%) with their patients. CONCLUSION: Asymptomatic diagnosis of oral cancer at an earlier stage of disease is possible in the primary medical setting but increased awareness and knowledge are required in both patients and health practitioners.

The ENHANCES study: a randomised controlled trial of a nurse-led survivorship intervention for patients treated for head and neck cancer.

PURPOSE: A randomised controlled trial was conducted to evaluate the effectiveness of a nurse-delivered Head and Neck Cancer Survivor Self-Management Care Plan (HNCP) for patients who had completed treatment for head and neck cancer (HNC). METHODS: Ten oncology nurses were trained to deliver the HNCP. The HNCP consisted of one face-to-face hour-long meeting in which the patient's treatment was recorded, as were contact details of health professionals involved in their care and follow-up schedules. Patients were guided to nominate up to three goals for their future well-being and assisted to devise an action plan to achieve these. The HNCP was given to the patient and a copy was forwarded to their primary care physician. One hundred and nine patients were randomised after definitive curative intent treatment, 36 to HNCP, 36 to receive information about survivorship, and 37 to usual care. The primary outcome, analysed by intention-to-treat, was change in quality of life measured by the FACT-H&N from baseline to 6-month follow-up. RESULTS: Quality of life of all groups decreased at 3 months but was close to baseline at 6 months. Compared with the usual care group, the only statistically significant mean difference at 6 months was for the information group on the physical well-being domain (mean difference 0.4, 95% - 1.8, 2.6, p < 0.05). CONCLUSIONS: A single-session nurse-delivered intervention is insufficient to improve the quality of life in HNC survivors compared with usual care. Provision of detailed written information about HNC survivorship is associated with improved physical well-being. TRIAL REGISTRATION: ACTRN12613000542796.

A culture shock in dental hygiene: Exploring the management of oral health after head and neck cancer.

OBJECTIVES: Managing oral health after the treatment for head and neck cancer requires meticulous daily oral hygiene practices and regular professional dental care; however, the individual factors and health system structures required to achieve oral health are often not well considered. This study aimed to explore how oral health was understood and managed after head and neck cancer treatment and identify factors that influenced oral health behaviours and dental service utilization. METHODS: A qualitative, inductive approach was used for data collection and analysis. Sampling of participants was purposive, using a maximum variation approach, and data were analysed using thematic analysis. Participants were recruited from the maxillofacial clinic at a tertiary facility in Brisbane, Queensland, Australia. RESULTS: Twenty-one participants took part in the study. Findings described individual and structural factors that influenced the management of oral health post-treatment. Individual determinants of oral health behaviours included a cognitive shift towards lifelong oral health; management of unexpected barriers; and management of competing priorities. Structural factors included availability, accessibility of services, and continuity of care. The ability to fund oral health emerged as a salient theme that influenced both individual and structural factors. CONCLUSIONS: Strong self-efficacy and financial and spousal support enhanced the management of oral health, whereas difficulty managing competing issues post-treatment, such as psychological and financial stress, limited participants' capacity to prioritize and manage oral health. Policy initiatives are needed to address the structural barriers caused by a lack of timely access to general and preventive dental care post-treatment.

Postoperative Radiotherapy for Oral Squamous Cell Carcinoma With Histologic Risk Factors: Are We Over-Treating?

PURPOSE: The role of postoperative radiotherapy (PORT) remains controversial for patients with low-risk oral squamous cell carcinoma (OSCC) and adverse histologic features. The aim of this study was to examine the survival benefits in the role of PORT, when compared with surgery alone, among these patients. MATERIALS AND METHODS: In this systematic review, relevant published literature was identified in the PubMed database and eligible studies were included. Predictor variables were perineural invasion (PNI), lymphovascular invasion, and unfavorable grade. The primary outcomes were patient survival and recurrence rates. Because of the heterogeneity and insufficiency of the reported data, quantitative meta-analysis was precluded. Qualitative analysis and pooled analysis on overall survival were performed for study patients. RESULTS: Six eligible studies were included, with a median study period of 10 years. All studies evaluated the role of PORT in pN0 OSCC patients with PNI, and 3 studies evaluated the role of PORT in patients with PNI in isolation. Overall, study patients had similar treatment outcomes between the PORT and non-PORT groups. In the pooled analysis of 325 patients, PORT was not associated with an improved overall survival rate compared with surgery alone (70.3% vs 80.2%, P = .059). CONCLUSIONS: No evidence was found to support the application of PORT given the indication of histologic risk factors alone. The prescription of PORT for PNI, lymphovascular invasion, and unfavorable grading among otherwise low-risk OSCC needs to be approached with caution to avoid the unnecessary harm of radiation exposure.

Increasing Use of Intensive Care Unit for Odontogenic Infection Over One Decade: Incidence and Predictors.

PURPOSE: To determine whether intensive care unit (ICU) admissions for odontogenic infections have increased during the past decade and whether certain clinical features are associated with a greater rate of ICU admission. MATERIALS AND METHODS: The data from patients undergoing surgery for odontogenic infections at the Royal Brisbane and Women's Hospital in the 24 month from January 2003 to December 2004 were compared with those from patients treated from January 2013 to December 2014. A χ2 analysis was used to compare the demographic, admission, and clinical patient data in each cohort. A multiple logistic regression model was used to determine which clinical features were associated with greater rates of ICU admission. RESULTS: The rate of ICU admission increased significantly from 7 to 24% during the decade (χ2 = 12.74; P = .000), although the clinical presentation of patients admitted to the ICU was similar in both cohorts. The mean number of days spent in the ICU increased significantly from 1.7 ± 0.5 to 3.24 ± 2.5 days (t = -3.63; P = .001), and the overall length of stay increased from 1.7 ± 0.5 to 3.5 ± 4.1 days (t = 2.99; P = .004). The use of preoperative computed tomography (CT) increased significantly from 42.9 to 93.3% (χ2 = 13.25; P = .000). The most significant predictors of ICU admission were lower third molar involvement (P = .026), dysphagia (P = .020), and C-reactive protein (CRP) levels exceeding 150 mg/L (P = .039). CONCLUSIONS: The use of the ICU in the management of odontogenic infection has increased significantly at the Royal Brisbane and Women's Hospital over 1 decade. The demographic data and clinical presentation of the patients admitted to the ICU did not change significantly. However, the length of ICU stay and the total length of stay have both increased. A significant increase in CT usage for odontogenic infections also occurred. Third molar infections, dysphagia, and elevated CRP might be relevant clinical predictors of a more complicated course of care requiring ICU admission. More judicious use of CT scanning, combined with prompt surgical consultation and intervention, might reduce the rate of ICU admissions for odontogenic infections.

A Tip for the Reconstruction of Larger Maxillary Defects in Complicated Cleft Patients.

Residual alveolar cleft deficits can be difficult to treat. This is particularly the case in older and multiply operated patients as well as those with large oronasal defects and extensive scar tissue. In large and recalcitrant defects vascularized free tissue transfer should be considered as a definitive procedure. Vascularized free tissue transfer provides a 95% success rate and provides excellent bone for placement of osseointegrated implants for dental rehabilitation (Schwabegger et al., 2004). We feel that the scapula tip has a number of important advantages. These include reduced morbidity from the donor site, good bone quality and contour for implant placement, and a longer pedicle length.

Quality of life of head and neck cancer patients in urban and regional areas: An Australian perspective.

OBJECTIVE: Head and neck cancer treatment affects quality of life. There are differences in quality of life outcomes and perceived supportive care needs between cancer patients living in metropolitan and regional-remote areas. This study investigated quality of life over the first 6 months following head and neck cancer diagnosis and observed differences in quality of life by geographical location. DESIGN: Prospective observational study. SETTING: Tertiary hospital in Brisbane, Australia. PARTICIPANTS: Newly diagnosed patients who were referred for the diagnosis, and/or treatment of head and neck cancer. MAIN OUTCOME MEASURE(S): Quality of life was measured by the University of Washington Quality of Life Survey, version 4 (UW-QoL). Participants completed the UW-QoL questionnaire prior to starting treatment, 1 month and 6 months post treatment. Metropolitan and regional or remote status was classified according to the Australian Standard Geographic Classification-Remoteness Area system. RESULTS: Ninety-five participants were included at baseline; 49 and 41 participants completed the 1-month and 6-month follow-ups, respectively. Scores in most UW-QoL domains decreased between baseline and 1 month post treatment and increased towards pre-treatment scores at the 6-month follow-up (except for anxiety and saliva). Pain at baseline was significantly worse in the regional-remote participants compared with metropolitan participants. No other statistically significant differences in UW-QoL score by geographical location were observed. CONCLUSION: The findings generally did not support significant differences in quality of life outcome between metropolitan and regional-remote head and neck cancer patients. The difference in pain experience between metropolitan and regional-remote groups requires further investigation.

High-Volume Surgeons Deliver Larger Surgical Margins in Oral Cavity Cancer.

PURPOSE: In oral cavity cancer surgery there are many factors that contribute to the surgical margin; thus, the factors determining patient outcomes are still not completely understood. The aim of this study was to determine which variable or variables had the greatest influence on increasing the size of the surgical margin. MATERIALS AND METHODS: A retrospective cohort study was conducted at the Royal Brisbane and Women's Hospital of patients who underwent resective surgery for a primary oral cavity cancer from January 1, 2008 through December 31, 2012. The primary outcome variable was the surgical margin, defined as the closest distance between the surgical edge and invasive cancer. A heterogeneous set of predictor variables was identified as potentially affecting the primary outcome variable: demographic, 5 surgical, and 7 histologic variables. The data then underwent statistical analysis using univariable linear regression, and variables that were found to have a statistical association were retained in a non-interaction multivariable model. RESULTS: This study included 250 patients. The results showed that high-volume surgeons delivered larger surgical margins than low-volume surgeons. The single most important variable associated with larger surgical margins was who performed the resective operation. The following variables also were associated with smaller surgical margins: retromolar trigone location, non-squamous cell carcinomas, perineural invasion, and a lip-split mandibulectomy surgical approach. CONCLUSION: There was a strong association between high-volume surgeons and larger surgical margins, supporting the rationalization of oral cavity cancer management in high-volume centers and by high-volume surgeons.

Primary angiosarcoma of the mandible: a case report.

Angiosarcomas are rare but aggressive vascular cancers of endothelial cell origin. Characteristically, they have a high local recurrence rate and an early metastatic potential. They rarely migrate to the skeleton, and even more unlikely, they may originate in the bones of the face. We present a rare occurrence of a primary angiosarcoma of the mandible. This case highlights the scarce literature available and difficulties in diagnosing and managing this aggressive tumor.

Impact of dental state and surgical factors on postoperative neck infection in oral cancer patients.

Postoperative neck infection (PONI) is a known complication of neck dissection. In this study we explored the impact of dental status on the development of PONI, using orthopantomograms to assess edentulism, periodontal health, and caries status. Retrospective analysis was performed for all new oral cancer patients who had neck dissection between January 2008 and January 2020 in a tertiary head and neck centre. PONI risk factors assessed included patient characteristics, dental status, tumour, and surgical factors. Development of PONI was the primary outcome. Edentulous patients had lower risk of PONI (OR 0.06, p = 0.026) compared to those with 21 or more teeth. Periodontitis and dental caries were not statistically significant. Current smokers (OR 2.09, p = 0.044) and free flap reconstruction (OR 5.41, p < 0.001) were also significant predictors for development of PONI. This study highlights the presence of teeth as a potential source of infection post neck dissection and that orthopantomogram assessment may be inadequate to identify at risk patients. Future studies are required on direct clinical assessment of dentition to evaluate the impact of dental optimisation in prevention of PONI.

Human papillomavirus associated oropharyngeal cancer now the most common mucosal head and neck cancer in Queensland.

INTRODUCTION: The profile and outcomes of head and neck cancer throughout Australia has changed over the past decade. The aim of this study was to perform a population-based analysis of incidence, demographics, stage, treatments and outcomes of patients diagnosed with oropharyngeal squamous cell carcinoma (OPSCC), with a particular focus on HPV-associated disease. METHODS: This was a retrospective analysis of prospectively collected data within the Queensland Oncology Repository (QOR) and analysed by the Queensland Cancer Control Analysis Team. The cohort included patients diagnosed in Queensland between 1 January 2015 and 31 December 2019. Outcome measures included incidence of new OPSCC cases, age-standardised rates (ASR) (3-year average), demographics, p16 status, stage (8th Edition American Joint Commission on Cancer), treatments, and 2- and 5-year overall survival. RESULTS: There were 1527 newly diagnosed OPSCC, representing 96% (1527/1584) of all oropharyngeal cancers. It was the most common head and neck cancer diagnosed, with oral cavity cancer being the second most common (n = 1171). Seventy-seven percent were p16 positive (1170/1527), of which 87% (1019/1170) were male. The median age was 61 years and 49% (568/1170) presented with Stage I disease. The ASR was 6.3/100,000, representing a 144% incidence increase since 1982 (2.6/100,000). Radiotherapy was utilised in 91% of p16+ cases with 2- and 5- year overall survival of 89% and 79%, respectively. CONCLUSION: OPSCC is now the most common mucosal head and neck cancer diagnosed in Queensland, having surpassed oral cavity cancer. The majority are HPV-associated (p16+), presenting with early-stage disease with a favourable prognosis.

A novel saliva-based miRNA profile to diagnose and predict oral cancer.

Oral cancer (OC) is the most common form of head and neck cancer. Despite the high incidence and unfavourable patient outcomes, currently, there are no biomarkers for the early detection of OC. This study aims to discover, develop, and validate a novel saliva-based microRNA signature for early diagnosis and prediction of OC risk in oral potentially malignant disorders (OPMD). The Cancer Genome Atlas (TCGA) miRNA sequencing data and small RNA sequencing data of saliva samples were used to discover differentially expressed miRNAs. Identified miRNAs were validated in saliva samples of OC (n = 50), OPMD (n = 52), and controls (n = 60) using quantitative real-time PCR. Eight differentially expressed miRNAs (miR-7-5p, miR-10b-5p, miR-182-5p, miR-215-5p, miR-431-5p, miR-486-3p, miR-3614-5p, and miR-4707-3p) were identified in the discovery phase and were validated. The efficiency of our eight-miRNA signature to discriminate OC and controls was: area under curve (AUC): 0.954, sensitivity: 86%, specificity: 90%, positive predictive value (PPV): 87.8% and negative predictive value (NPV): 88.5% whereas between OC and OPMD was: AUC: 0.911, sensitivity: 90%, specificity: 82.7%, PPV: 74.2% and NPV: 89.6%. We have developed a risk probability score to predict the presence or risk of OC in OPMD patients. We established a salivary miRNA signature that can aid in diagnosing and predicting OC, revolutionising the management of patients with OPMD. Together, our results shed new light on the management of OC by salivary miRNAs to the clinical utility of using miRNAs derived from saliva samples.

Improving accuracy in nodal staging of oral cancer: Proposal of a new system.

BACKGROUND: Despite introduction of extranodal extension (ENE) into the AJCC 8th edition of oral cancer staging, previous criticisms persist, such as limited discrimination between sub-stages and doubtful prognostic value of contralateral nodal disease. The purpose of this study was to compare our novel nodal staging system, based on the number of positive nodes and ENE, to the AJCC staging system in surgically treated patients. METHODS: Retrospective analysis of 4710 patients with oral squamous cell carcinoma (OSCC) treated with surgery±adjuvant therapy in 8 institutions in Australia, North America and Asia. With overall survival (OS) and disease specific survival (DSS) as endpoint, the prognostic performance of AJCC 8th and 7th editions were compared using hazard consistency, hazard discrimination, likelihood difference and balance. RESULTS: Our new nodal staging system (PN) a progressive and linear increase in hazard ratio (HR) from pN0 to pN3, with good separation of Kaplan Meier curves. Using the predetermined criteria for evaluation of a staging system, our proposed staging model outperformed AJCC 8th and 7th editions in prediction of OS and DSS. CONCLUSION: PN was the lymph node staging system that provided the most accurate prediction of OS and DSS for patients in our cohort of OSCC. Additionally, it can be easily adopted, addresses the shortcomings of the existing systems and should be considered for future editions of the TNM staging system.

Workflow for Fabricating 3D-Printed Resorbable Personalized Porous Scaffolds for Orofacial Bone Regeneration.

Resorption of alveolar bone following tooth extraction is a physiological process that can often prevent the placement of dental implants due to the limited bone remaining. In severe cases, vertical bone augmentation, which aims to restore bone in an extraskeletal dimension (outside of the skeletal envelope), is required prior to implant placement. While current treatment strategies rely on autologous grafts, or "Guided Bone Regeneration" involving the placement of particulate bone grafting biomaterials under a protective membrane, the field is shifting to patient-matched solutions. Herein, we describe the various steps required for modeling the patient data, creating the patient-matched scaffold geometry and 3D-printing using the biodegradable polymer polycaprolactone for application in the oro-dental and craniofacial areas.

The dental management of patients irradiated for head and neck cancer.

Patients undergoing radiotherapy for head and neck cancers are prone to a range of dental complications, including mucositis, trismus, xerostomia, radiation caries and osteoradionecrosis. Specific considerations include the preventive, restorative and rehabilitative management of such patients, and the prevention and treatment of complications. This article aims to highlight the current understanding and management of dental needs for patients who have had or will undergo radiotherapy.

Prediction nomogram development and validation for postoperative radiotherapy in the management of oral squamous cell carcinoma.

BACKGROUND: Predictive nomograms are useful tools to guide clinicians in estimating disease course. Oral squamous cell carcinoma (OSCC) patients would benefit from an interactive prediction calculator that defines their levels of survival-risk specific to their tumors to guide the use of postoperative radiotherapy (PORT). METHODS: Patients with OSCC surgically treated with curative intent at four Head and Neck Cancer Centres were recruited retrospectively for development and validation of nomograms. Predictor variables include PORT, age, T and N classification, surgical margins, perineural invasion, and lymphovascular invasion. Outcomes were disease-free, disease-specific, and overall survivals over 5 years. RESULTS: 1296 patients with OSCC were in training cohort for nomogram analysis. Algorithms were developed to show relative benefit of PORT in survivals for higher-risk patients. External validation on 1212 patients found the nomogram to be robust with favorable discrimination and calibration. CONCLUSION: The proposed calculator can assist clinicians and patients in the decision-making process for PORT.