Potential risk factors for jaw osteoradionecrosis after radiotherapy for head and neck cancer

Analysis of health insurance data on dental treatment and the occurrence of osteoradionecrosis of the jaw

BACKGROUND

Radiotherapy (RT) is a key component in the multimodal treatment approach for head and neck cancer (HNC). Post-therapeutic surgical and/or dental interventions on the jawbone carry a risk of developing osteoradionecrosis (ORN). To mitigate this risk, dental examinations and, if necessary, treatment should be conducted prior to RT. However, the consistent implementation of these recommendations in routine dental practice remains uncertain. This study aimed to evaluate whether insured persons of AOK Saxony-Anhalt (AOK ST) utilise dental services in accordance with current treatment recommendations and whether this behaviour influences the need for post-therapeutic tooth removal and the occurrence of ORN.

METHODS

Anonymised health claims data were analysed from individuals newly diagnosed with HNC between 2017 and 2021, who received RT and were continuously insured by AOK ST from 1 year before the start of RT to 2022. Three dependent variables were evaluated: dental treatment prior to RT, tooth extraction after RT, and ORN occurrence. Independent variables included sex, age, tooth extraction before RT, need for care, exemption from copayment, bisphosphonate prescription, diabetes, chronic obstructive pulmonary disease, alcohol abuse, chemotherapy, and guideline adherence.

RESULTS

Data from 1,086 patients with HNC diagnoses (75.9% male) were analysed. The median follow-up time from the first RT was 796 days (first quartile: 316 days; third quartile: 1,210 days). Twenty-one patients (1.9%) developed ORN after RT. More than 50% of the study population received dental care in accordance with guideline recommendations prior to RT. Need for care had the most significant negative effect on the utilisation of dental treatment prior to RT.

CONCLUSION

This study did not find evidence of consistent implementation of the recommended guidelines for dental assessment/therapy prior to RT. Patients in need for care and those with chronic comorbidities were less likely to receive and/or require dental care. Although no significant influence on ORN development was observed, the reliability of this finding is limited by the small cohort size and low ORN incidence. Further studies with larger cohorts are needed to validate these findings.

Pan-immune-inflammatory value and systemic immune-inflammatory index in relation to osteoradionecrosis of the jaws: a single institutional experience over 15 years

Osteoradionecrosis of the jaws (ORNJ) is a pernicious complication of radiation therapy that significantly affects the quality of life of patients with head and neck cancer. The present study aims to investigate the risk factors for the clinical prognosis of ORNJ in the same scenario. A cross-sectional study was designed and implemented in a tertiary teaching hospital from January 2005 to December 2020. A total of 106 patients were divided into normal wound-healing group (n = 79) and delayed wound-healing group (n = 27) according to two different prognosis. The risk factors associated with the prognosis in patients with ORNJ were comparatively analyzed via performing one-way and multifactorial logistic analyses. The majority of the study cohort (n = 59, 55.7%) was found to be characterized with Glanzmann and Gratz grade 2 and followed up for a median of 38.6 months. Diabetes mellitus (p = 0.045), Charlson comorbidity index (p = 0.042), American Society of Anesthesiologists score (p < 0.001), primary tumor site (p = 0.012), T stage (p = 0.008), ORNJ grade at initial diagnosis (p < 0.001), pan-immune-inflammatory value and systemic immune-inflammatory index at initial radiotherapy (p = 0.01 and p < 0.001 respectively) were detected as risk factors associated with poor prognosis in patients with ORNJ. We conclude that there are abundant risk factors for poor prognosis in these patients, and it is important to be evaluated before irradiation so that suitable post-radiated treatments can be given.

Critical review of patient outcome study in head and neck cancer radiotherapy

Rapid technological advances in radiation therapy have significantly improved dose delivery and tumor control for head and neck cancers. However, treatment-related toxicities caused by high-dose exposure to critical structures remain a significant clinical challenge, underscoring the need for accurate prediction of clinical outcomes-encompassing both tumor control and adverse events (AEs). This review critically evaluates the evolution of data-driven approaches in predicting patient outcomes in head and neck cancer patients treated with radiation therapy, from traditional dose-volume constraints to cutting-edge artificial intelligence (AI) and causal inference framework. The integration of linear energy transfer in patient outcomes study, which has uncovered critical mechanisms behind unexpected toxicity, was also introduced for proton therapy. Three transformative methodological advances are reviewed: radiomics, AI-based algorithms, and causal inference frameworks. While radiomics has enabled quantitative characterization of medical images, AI models have demonstrated superior capability than traditional models. However, the field faces significant challenges in translating statistical correlations from real-world data into interventional clinical insights. We highlight that how causal inference methods can bridge this gap by providing a rigorous framework for identifying treatment effects. Looking ahead, we envision that combining these complementary approaches, especially the interventional prediction models, will enable more personalized treatment strategies, ultimately improving both tumor control and quality of life for head and neck cancer patients treated with radiation therapy.

Association between microvascular free-flap arterial anastomosis caliber and risk for development of osteoradionecrosis

OBJECTIVES

Osteoradionecrosis (ORN) following radiation therapy (RT) is a serious complication for patients undergoing head and neck cancer treatment. Recent literature has found an association between ipsilateral external carotid artery (ECA) diameter and the development of ORN. This study evaluates microvascular free-flap arterial anastomosis diameter and the development of ORN.

MATERIALS AND METHODS

Sixty-six patients underwent fibular free-flap reconstruction followed by RT between 2012-2019 at the University of Florida. Anastomosis and ECA diameters pre- and post-RT were measured from computed tomography images. Multivariate regression analysis identified significant factors in the development of ORN.

RESULTS

Incidence of ORN was 33.3 % (N = 22/66). Mean post-RT anastomosis diameters were 2.3 and 2.2 for the ORN group and no-ORN group, respectively (p = 0.548). Mean post-RT ipsilateral ECA diameters were 4.7 and 4.2 for the ORN group and no-ORN groups, respectively (p = 0.040). The change in pre-RT versus post-RT ipsilateral ECA diameters was different in patients with RT dose above and below 55 Gy (p = 0.041). Neither post-RT anastomosis (OR = 1.78, 95% CI: 0.43, 8.65, p = 0.434), nor ECA (OR = 1.44, 95% CI: 0.78, 2.83, p = 0.250) diameters were associated with development of ORN while controlling RT dose (OR = 1.15, 95% CI: 1.04, 1.28, p = 0.006), post-operative fistula (OR = 9.11, 95% CI: 1.65, 93.7, p = 0.010), and post-operative infection (OR = 3.48. 95% CI = 1.01, 12.7, p = 0.048), and CCI (OR = 0.61, 95 % CI: 0.36, 0.96, p = 0.031).

CONCLUSION

A higher degree of narrowing in ipsilateral ECA following RT may be linked to development of ORN. RT doses ≥ 55 Gy were associated with a high risk of ORN.

Effectiveness of a protocol with antimicrobial photodynamic therapy for treating osteoradionecrosis: a retrospective study

OBJECTIVE

To compare the treatment of osteoradionecrosis (ORN) using a protocol that incorporates antimicrobial photodynamic therapy with a conventional treatment protocol.

METHODOLOGY

This retrospective study analyzed 55 patients diagnosed with ORN at a reference hospital between 2002 and 2021. Patients were treated using two different clinical protocols. Clinical treatment success was defined as the epithelialization of the ORN lesion, along with the absence of pain and local infection.

RESULTS

A total of 53 ORN lesions were included, with a median development time of 30 months. The patient cohort was predominantly male (83.02%), with a median age of 58 years. The main causes of ORN were prosthetic trauma (28.30%) and dental extractions due to infection (32.07%). Good oral hygiene and hygiene of the lesion were identified as protective factors for achieving clinical success, with a significant correlation to lesion epithelialization (p ≤ 0.0001). ORN developed more rapidly in tumors of the oral cavity, with a median time of 8 months, compared to oropharyngeal tumors, which had a median time of 39 months (p = 0.01).

CONCLUSION

The proposed treatment protocol, which includes antimicrobial photodynamic therapy, demonstrated greater effectiveness compared to the conventional protocol, achieving clinical success in 75% of the lesions analyzed in a shorter timeframe (p ≤ 0.0001). Additionally, maintaining proper oral and lesion hygiene is crucial for successful outcomes, and ORN develops more rapidly in patients with oral cavity tumors.

Prognostic Factors of Mandibular Osteoradionecrosis Including Accurate Colocalization of Avulsions and Dosimetric Dental Mapping Software, a Case-control Study

PURPOSE

Osteoradionecrosis (ORN) of the mandible remains a significant complication in the intensity modulated radiation therapy (IMRT) era. Dental dose cannot be predicted from heterogeneous IMRT dose distributions; mandibular dose metrics cannot guide dentist avulsion decisions in high-risk ORN situations. Using a mapping tool to report dental root dose, avulsions, and ORN sites, we re-examined ORN risk factors in a case-control study.

METHODS AND MATERIALS

From 2008 to 2019, 897 consecutive patients with oral cavity/oropharynx or unknown primary cancer undergoing IMRT were analyzed to identify ORN cases. These were matched (1 ORN/2 controls) retrospectively for tumor location, surgery, and tobacco consumption in a monocentric case-control study. Univariate and multivariate analyses integrated ORN factors and accurate dental dose data (grouped into 4 mandibular sectors). Generalizability was investigated in a simulated population database.

RESULTS

A total of 171 patients were included. The median follow-up was 5.2 and 4.5 years in the ORN and control groups, respectively. The median time to ORN was 12 months. In univariate analysis, post-IMRT avulsions at the ORN site (hazard ratio [HR] = 3.6; 95% confidence interval [CI] = 1.5-8.9; P = .005), tumor laterality (HR, 4.4; 95% CI, = 1.4-14, P = .01), mean mandibular dose (HR, 1.1; 95% CI, = 1.01-1.1; P = .018) and mean dose to the ORN site (HR, 1.1; 95% CI, = 1.1-1.2; P < .001) correlated with higher ORN risk. In multivariate analysis, mean dose to the ORN site (HR, 1.1; 95% CI, = 1.1-1.2; P < .001) and post-IMRT avulsions at the ORN site (HR, 4.6; 95% CI, = 1.5-14.7; P = .009) were associated with ORN. For each increase in gray in dental dose, the ORN risk increased by 12%. Simulations confirmed study observations.

CONCLUSIONS

Dental dose and avulsions are associated with ORN, with a 12% increase in risk with each additional gray. Accurate dose information can help dentists in their decisions after IMRT.

Timing of development of osteoradionecrosis post head and neck radiotherapy: does a safe time interval exist for dental extraction?

INTRODUCTION

Risk factors for developing osteoradionecrosis (ORN) are well known, but less is known about factors influencing the interval between radiotherapy and the onset of ORN. Also, it is unknown whether there is any specific period post-radiotherapy with a reduced probability of ORN when irradiated teeth require extraction.

PURPOSE

The primary aim of this study was to identify factors influencing the interval in developing ORN in the following subgroups of patients: (1) patients who spontaneously developed ORN, (2) surgical-intervention-related ORN with a particular focus on patients after mandibulectomy. The secondary aim was to attempt to identify a possible time for safer dental intervention after primary treatment.

MATERIALS AND METHODS

The authors retrospectively analysed 1608 head and neck cancer (HNC) patients treated in a single centre. Time intervals were measured from the end of radiotherapy to the development of ORN and further analysed in the subgroups listed above.

RESULTS

In all, 141 patients (8.8%) developed intra-oral ORN. Median time from radiotherapy to ORN development in the whole cohort was 9 months. Median interval for spontaneous ORN was 8 months, 6.5 months for intervention-related ORN, and 15 months for patients post-mandibulectomy. In patients who required dental extraction preradiotherapy, median interval of ORN onset was 5 months.

CONCLUSION

In our study, a slightly higher proportion of patients with intervention developed ORN earlier in comparison with spontaneous ORN. The period from 12-18 months after radiotherapy was identified as having the highest probability of developing ORN in patients after mandibulectomy. A time for safer dental intervention after primary treatment was not identified.

Effect of Statins on Patients With Osteoradionecrosis of the Jaw

BACKGROUND

Osteoradionecrosis of the jaw (ORN) is a late complication of radiation therapy. Radiation-induced fibrosis is the most likely mechanism for developing ORN, and statins are effective against radiation-induced fibrosis. However, no reports have indicated the direct effectiveness of statins in treating ORN.

PURPOSE

This study aimed to measure the association between statin exposure and ORN disease resolution.

STUDY DESIGN, SETTING, SAMPLE

This retrospective cohort study included patients with ORN diagnosed between January 2008 and December 2020 at the Hospital's Department of Oral and Maxillofacial Surgery. Patients who were immunocompromised or followed up for < 6 months were excluded.

PREDICTOR VARIABLE

The predictor variable was statin exposure, which was defined as the use of statins for dyslipidemia.

MAIN OUTCOME VARIABLE

The main outcome variable was ORN disease progression status (good prognosis). Patients who showed full recovery and improvement were included in the good prognosis group, and those who showed invariance and deterioration were included in the poor prognosis group.

COVARIATES

We analyzed the clinicodemographic including the age of onset, sex, history of smoking, alcohol consumption, history of chemotherapy, tumor site, association with dental treatment, location (maxilla or mandible), the time to ORN onset from radiation therapy, and stage of ORN, and treatment characteristics including hyperbaric oxygen therapy, long-term macrolide administration, and sequestrectomy.

ANALYSES

We analyzed the association between statin exposure or covariates and time to ORN improvement using bivariate and multivariate Cox regression. The significance level was set at P = .05.

RESULTS

We analyzed 102 patients, and the improvement rate was 32.4%. The favorable prognostic factors were statin exposure (adjusted hazard ratio [HR], 3.71; 95% confidence interval [CI], 1.62 to 8.50; P = .002), onset in the maxilla (HR, 2.15; 95% CI, 1.02 to 4.55; P = .045), and stage 1 of ORN (HR, 2.65; 95% CI, 1.20 to 5.83; P = .016).

CONCLUSION AND RELEVANCE

In this study, statin exposure, onset in the maxilla, and stage 1 of Lyons's classification were favorable prognostic factors for ORN. Although this study's findings were insufficient to recommend statin use for ORN, statins may be a novel and effective treatment for ORN.

The incidence of osteoradionecrosis of the jaws in oral cavity cancer patients treated with intensity-modulated radiotherapy: a systematic review and meta-analysis

OBJECTIVE

A systematic review with meta-analysis was conducted to define the incidence of osteoradionecrosis (ORN) in patients with oral cavity cancer (OCC) treated with intensity-modulated radiotherapy (IMRT), and to identify the risk factors influencing its development.

STUDY DESIGN

Six databases were searched systematically. A meta-analysis was performed to determine overall, spontaneous, and dental extraction-attributed incidences of ORN. The Grading of Recommendations Assessment, Development, and Evaluation tool evaluated evidence certainty.

RESULTS

Out of 11 eligible studies, 6 underwent meta-analysis for the overall aggregated ORN incidence in OCC patients receiving IMRT, resulting in an incidence rate of 8% (95% CI: 6%-11%). Regarding development reasons, 2 studies were assessed, revealing an incidence of 36% (95% CI: 1%-98%) for spontaneous ORN, and 17% (95% CI: 5%-44%) ensued from dental extraction exclusively pre-RT. All rates had very low certainty of evidence. Factors significantly correlated with ORN development included postoperative RT use (78%), employment of therapeutic doses above 50 Gy, and mandibular involvement (80.5%).

CONCLUSION

The findings suggest that IMRT alone is not sufficient to decrease ORN rates in OCC patients, underscoring the importance of precisely identifying the involved risk factors. However, further detailed primary studies will be necessary.

Osteoradionecrosis Rates After Head and Neck Radiation Therapy: Beyond the Numbers

PURPOSE

Osteoradionecrosis (ORN) is a severe late complication of head and neck radiation therapy shown to have profound negative effect on the quality of life of cancer survivors. Over the past few decades, improvements in radiation delivery techniques have resulted in a decrease in the incidence of ORN. However, even with modern radiation therapy techniques, ORN remains an important clinical concern. In recent literature, there is a wide range of reported ORN rates from 0% to as high as 20%. With such a high level of variability in the reported incidence of ORN, oncologists often encounter difficulties estimating the risk of this serious radiation therapy toxicity.

METHODS AND MATERIALS

In this review, the authors present a summary of the factors that contribute to the high level of variability in the reported incidence of ORN.

RESULTS

Variable definition, variable grading, and heterogeneity of both study inclusion criteria and treatment parameters can each significantly influence the reporting of ORN rates.

CONCLUSIONS

Given numerous factors can affect the reported incidence of ORN, a thorough understanding of the clinical context behind the reported ORN rates is needed to comprehend the true risk of this important radiation therapy toxicity.

Good Gone Bad: Complications of Chemotherapy, Immunotherapy, and Radiotherapy on the CNS

With recent advancements in cancer therapy, especially immunotherapy, overall survival of many cancers has increased and patient toxicity has been reduced. However, many complications of traditional cancer therapy are still prevalent and complications of novel therapies are just beginning to appear. The neuroradiologist may be the first to visualize signs of these complications on imaging. This article describes the notable imaging findings of several unique and characteristic complications of CNS cancer therapy, including toxicities of chemotherapies, immunotherapies, and radiotherapy. Complications of chemotherapeutic agents covered include methotrexate-induced and disseminated necrotizing leukoencephalopathy, and chemotherapy-induced myelopathy. Immunotherapy complications included are Tacrolimus-related Optic Neuropathy, Rituximab and Immune reconstitution inflammatory syndrome-associated Progressive Multifocal Leukoencephalopathy, Bevacizumab-associated late radiation-induced neurotoxicity, and Ipilimumab-induced hypophysitis. Lastly, radiation-induced neurotoxicities are covered, including myelopathy, radiation necrosis, cerebral atrophy, leukoencephalopathy, optic neuropathy, mineralizing microangiopathy, stroke-like migraine attacks, osteonecrosis, and vasculopathies. Neuroradiologists will increasingly encounter patients who have undergone treatment with more than 1 therapeutic modality, resulting in overlapping findings as well. Recognition of the common complications of these therapies on imaging is critical to minimizing the effects of these potential short- and long-term complications.

Long-term follow-up of osteoradionecrosis of the mandible

AIM

Investigating the prevalence of mandibular ORN in a single Swedish Oncology Center.

METHODS

A total of 450 patients, treated with radiotherapy for squamous cell carcinoma in the oropharynx between 2004 and 2014 were included. Three different techniques of radiotherapy were studied. ORN diagnosis was set when clinical signs according to Marx were observed, or if radiological signs were staged according to Schwartz and Kagan.

RESULTS

Using the staging system, 90 patients (20%) were diagnosed with ORN. The mean age of the ORN patients was 56.6 years, the older the patient the lower the risk of developing ORN (p = .01). The risk of developing ORN for patients receiving Intensity Modulated Radiotherapy was lower compared to patients treated with the other techniques in the multivariable analysis. Brachytherapy significantly increases the risk of ORN. The risk of ORN increased by 8% each year after radiation (p = .04). The mean time to the ORN diagnosis was 3.9 years. In the multivariate analysis, the risk of ORN increased by 13% each year after radiation (p = .0013).

CONCLUSION

The mean radiation dose was of greater importance for the risk of ORN than the maximum dose. Elderly people with oropharyngeal cancer were less prone to develop ORN.

Comparison of Machine-Learning and Deep-Learning Methods for the Prediction of Osteoradionecrosis Resulting From Head and Neck Cancer Radiation Therapy

Purpose

Deep-learning (DL) techniques have been successful in disease-prediction tasks and could improve the prediction of mandible osteoradionecrosis (ORN) resulting from head and neck cancer (HNC) radiation therapy. In this study, we retrospectively compared the performance of DL algorithms and traditional machine-learning (ML) techniques to predict mandible ORN binary outcome in an extensive cohort of patients with HNC.

Methods and Materials

Patients who received HNC radiation therapy at the University of Texas MD Anderson Cancer Center from 2005 to 2015 were identified for the ML (n = 1259) and DL (n = 1236) studies. The subjects were followed for ORN development for at least 12 months, with 173 developing ORN and 1086 having no evidence of ORN. The ML models used dose-volume histogram parameters to predict ORN development. These models included logistic regression, random forest, support vector machine, and a random classifier reference. The DL models were based on ResNet, DenseNet, and autoencoder-based architectures. The DL models used each participant's dose cropped to the mandible. The effect of increasing the amount of available training data on the DL models' prediction performance was evaluated by training the DL models using increasing ratios of the original training data.

Results

The F1 score for the logistic regression model, the best-performing ML model, was 0.3. The best-performing ResNet, DenseNet, and autoencoder-based models had F1 scores of 0.07, 0.14, and 0.23, respectively, whereas the random classifier's F1 score was 0.17. No performance increase was apparent when we increased the amount of training data available for DL model training.

Conclusions

The ML models had superior performance to their DL counterparts. The lack of improvement in DL performance with increased training data suggests that either more data are needed for appropriate DL model construction or that the image features used in DL models are not suitable for this task.

Efficacy of curcumin for amelioration of radiotherapy-induced oral mucositis: a preliminary randomized controlled clinical trial

BACKGROUND

Oral mucositis (OM) is one of the main problems in almost all patients undergoing head and neck radiotherapy (RT). Owning to the antioxidant and anti-inflammatory properties of curcumin, the effect of both oral and topical formulations of curcumin was assessed on radiation-induced OM (ROM) in this study.

METHODS

The safety and efficacy of curcumin mouthwash 0.1% (w/v) and curcumin-nanocapsule were evaluated in ameliorating severity and pain/burning associated with OM during RT. The current randomized, placebo-controlled trial was conducted on 37 patients with head and neck cancers. Patients with grades 1 to 3 of ROM were randomized to receive one of the three interventions: curcumin mouthwash (0.1% w/v); Sinacurcumin soft gel containing 40 mg curcuminoids as nano-micelles (SinaCurcumin®40); or placebo mouthwash with a similar transparent appearance to curcumin mouthwash for 1 min three times daily during RT. Study evaluations were conducted at baseline and weekly thereafter for up to 3 weeks using the Numeric rating scale (NRS) and world health organization (WHO) scale.

RESULTS

Among the 45 patients randomized, 37 (mean (SD) age of 53.36 (15.99) years; 14 [37.8%] women) completed the treatment according to the protocol. Patients treated with either oral or topical curcumin showed a significantly reduced severity and burning related to OM during the first 3 weeks after administration (P-Value < 0.001) as compared with the placebo. At study termination, more than 33% of subjects utilizing curcumin mouthwash and 15% of patients utilizing curcumin-nanocapsule remained ulcer free while all of the placebo-receiving subjects had OM. The reduction of NRS and WHO scale between curcumin groups was comparable without significant differences.

CONCLUSION

Both curcumin mouthwash and nanocapsule were effective, safe, and well-tolerated in the treatment of radiation-induced OM. Higher doses of curcumin and larger sample sizes can be used for further investigation in future studies.

TRIAL REGISTRATION

https://irct.ir/ IRCT20190810044500N17 (13/08/2021).

Early detection of mandible osteoradionecrosis risk in a high comorbidity veteran population

OBJECTIVE

Osteoradionecrosis (ORN) of the mandible is a devastating complication of external beam radiation therapy (EBRT) for head and neck squamous cell carcinoma (HNSCC). We sought to ascertain ORN risk in a Veteran HNSCC population treatment with definitive or adjuvant EBRT and followed prospectively.

STUDY DESIGN

Retrospective analysis of prospective cohort.

SETTING

Tertiary care Veterans Health Administration (VHA) medical center.

METHODS

Patients with HNSCC who initiated treatment at the Michael E. DeBakey Veterans Affairs Medical Center (MEDVAMC) are prospectively tracked for quality of care purposes through the end of the cancer surveillance period (5 years post treatment completion). We retrospectively analyzed this patient cohort and extracted clinical and pathologic data for 164 patients with SCC of the oral cavity, oropharynx, larynx, and hypopharynx who received definitive or adjuvant EBRT (2016-2020).

RESULTS

Most patients were dentate and 80 % underwent dental extractions prior to EBRT of which 16 (16 %) had complications. The rate of ORN was 3.7 % for oral cavity SCC patients and 8.1 % for oropharyngeal SCC patients. Median time to ORN development was 156 days and the earliest case was detected at 127 days post EBRT completion. All ORN patients were dentate and underwent extraction prior to EBRT start.

CONCLUSION

ORN development can occur early following EBRT in a Veteran population with significant comorbid conditions but overall rates are in line with the general population. Prospective tracking of HNSCC patients throughout the post-treatment surveillance period is critical to early detection of this devastating EBRT complication.

Factors Influencing the Survival Rate of Teeth and Implants in Patients after Tumor Therapy to the Head and Neck Region-Part 2: Implant Survival

During prosthetic rehabilitation after tumor therapy (TT) in the head and neck region, the dentist must assess whether the prognosis of the remaining teeth is sufficiently good or whether implants should be used to anchor dentures. Thus, the aim of the present study was to compare the survival rate of teeth and implants after TT and to evaluate factors potentially influencing implant survival. One hundred fifteen patients (male: 70.3%; mean age: 63.2 ± 12.4 years) having received dental treatment before and after TT at the Martin Luther University Halle-Wittenberg were enrolled in the study. Clinical examination including assessment of dental status and stimulated salivary flow rate was performed. Information about disease progression and therapy was retrieved from medical records. After TT, from a total of 1262 teeth, 27.2% had to be extracted. Of 308 implants inserted after TT, 7.0% were lost. Teeth exhibited lower 5-year survival probability (76.8%) than implants (89.9%; p = 0.001). The risk of loss (RL) of implants increased with age, nicotine use, intraoral defects, and RCT. Radiotherapy did not independently increase the RL. Thus, implants seem to be a reliable treatment option in case of progressive tooth decay after TT, particularly after RT.

Factors Influencing the Survival Rate of Teeth and Implants in Patients after Tumor Therapy to the Head and Neck Region-Part 1: Tooth Survival

We aimed to evaluate possible factors influencing the long-term survival of teeth after tumor therapy (TT) to the head and neck region with and without radiation. Between January 2019 and January 2020, patients who underwent TT for head and neck cancer and received dental treatment before and after TT at the Department of Prosthetic Dentistry of the Martin Luther University Halle-Wittenberg were enrolled in the study. Clinical examination with assessment of dental status and stimulated salivary flow rate (SFR) was performed and information about disease progression and therapy was retrieved from medical records. Of 118 patients (male: 70.3%; mean age: 63.2 ± 12.4 years), 95 received radiotherapy (RT), and 47 were administered radio-chemotherapy (RCT). The teeth of irradiated patients exhibited a lower 5-year survival probability (74.2%) than those of non-irradiated patients (89.4%). The risk of loss (RL) after RT increased with nicotine use, presence of intraoral defects, reduced SFR, RCT and regarding mandibular teeth, and decreased with crowning following TT. Lower SFR increased the RL even without RT. Consideration of patient's treatment history, individual risk profile, and clinical findings during the prosthetic planning phase could enable earlier, more targeted dental treatment after TT (e.g., timely crowning).

Osteoradionecrosis after postoperative radiotherapy for oral cavity cancer: A retrospective cohort study

OBJECTIVE

Osteoradionecrosis (ORN) is a severe late complication after radiotherapy but current knowledge on ORN risks in the setting of postoperative radiotherapy (PORT) is limited. We studied the incidence and risk factors of ORN in patients with oral cavity cancers (OCC, treated with PORT.

PATIENTS AND METHODS

A retrospective cohort study was conducted including OCC patients (mainly squamous cell) treated with postoperative intensity modulated radiotherapy between 2010 and 2018 with > 1 year disease-free survival. Cumulative incidences of ORN were computed using the Kaplan Meier method. Clinical and dosimetric risk factors for mandibular ORN were evaluated using Cox regression models.

RESULTS

Within our cohort (N = 227, median follow-up 49 months) we observed 46 cases of ORN, mainly in the mandible (n = 41). The cumulative incidence of mandibular ORN was 15.9 % (SE 2.5 %) at three years and 19.8 % (SE 3.0 %) at five years. At univariable analysis, smoking, mandibular mandibulotomy or segment resection, mean dose to the mandible, and mandible volume (%) ≥ 60 Gy (V60) were significantly associated with increased ORN risks. At multivariable analysis, smoking (HR 2.13, 95 %CI 1.12-4.06) and V60 (HR 1.02 per 1 % increase, 95 %CI 1.01-1.04) remained predictive factors. For active smokers with a high V60 ≥ 40 % we observed rapid ORN development with a 1-year incidence of 29 % vs 6 % for others (p < 0.01).

CONCLUSION

OCC Patients treated with PORT are at high risk for mandibular ORN. We identified the mandibular volume receiving ≥ 60 Gy as the dominant risk factor, especially in active smokers. Limiting high-dose volumes at treatment planning may decrease ORN risks.

Progression and postoperative complications of osteoradionecrosis of the jaw: a 20-year retrospective study of 124 non-nasopharyngeal cancer cases and meta-analysis

BACKGROUND

To assess the contributing risk factors for the progression of, and the postoperative poor prognosis associated with, osteoradionecrosis of jaw (ORNJ) following non-nasopharyngeal cancer treatment in head and neck.

METHODS

A retrospective study of 124 non-nasopharyngeal carcinoma patients in head and neck treated at one institution between 2001 and 2020 was conducted. A cumulative meta-analysis was conducted according to PRISMA protocol and the electronic search was performed on the following search engines: PubMed, Embase, and Web of Science. After assessing surgery with jaw lesions as a risk factor for the occurrence of ORNJ, 124 cases were categorized into two groups according to the "BS" classification, after which jaw lesions, chemotherapy, flap reconstruction and onset time of ORNJ were analyzed through the chi-square test and t-test to demonstrate the potential association between them and the progression of ORNJ. Postoperative outcomes of wound healing, occlusal disorders, and nerve injury were statistically analyzed.

RESULTS

With the statistically significant results of the meta-analysis (odds ratio = 3.07, 95% CI: 1.84-5.13, p < 0.0001), the chi-square test and t-test were used to validate our hypotheses and identified that surgery with jaw lesions could aggravate the progression and accelerate the appearance of ORNJ. Patients who underwent chemotherapy tended to suffer from severe-to-advanced osteonecrosis but did not shorten the onset time of ORNJ. Flap reconstruction presented obvious advantages in wound healing (p < 0.001) and disordered occlusion (p < 0.005). The mean onset time of ORNJ in non-nasopharyngeal cancer patients (4.5 years) was less than that in patients with nasopharyngeal cancer (NPC) (6.8 years).

CONCLUSIONS

Iatrogenic jaw lesions are evaluated as a significant risk factor in the occurrence and progression of ORNJ in non-nasopharyngeal carcinoma patients who tend to have more severe and earlier osteonecrosis after radiotherapy than NPC patients. Flap reconstruction is a better choice for protecting the remaining bone tissue and reducing postoperative complications of ORNJ.

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.

Conservative orthodontic treatment for severe pathologic migration following total glossectomy: A case report

Glossectomy combined with radiotherapy causes different levels of tongue function disorders and leads to severe malocclusion, with poor periodontal status in cancer survivors. Although affected patients require regular access to orthodontic care, special considerations are crucial for treatment planning. This case report describes the satisfactory orthodontic management for the correction of severe dental crowding in a 43-year-old female 6 years after treatment for tongue cancer with total glossectomy combined with radiotherapy, to envision the possibility of orthodontic care for oral cancer survivors. Extraction was performed to correct dental crowding and establish proper occlusion following alignment, after considering the possibility of osteoradionecrosis. Orthodontic mini-implants were used to provide skeletal anchorage required for closure of the extraction space and intrusion of the anterior teeth. The dental crowding was corrected, and Class I occlusal relationship was established after 36 months of treatment. The treatment outcome was sustained after 15 months of retention, and long-term follow-up was recommended.

Exposed bone in patients with head and neck cancer treated with radiation therapy: An analysis of the Observational Study of Dental Outcomes in Head and Neck Cancer Patients (OraRad)

BACKGROUND

Patients with head and neck cancer (HNC) treated with radiation therapy (RT) are at risk for jaw osteoradionecrosis (ORN), which is largely characterized by the presence of exposed necrotic bone. This report describes the incidence and clinical course of and risk factors for exposed intraoral bone in the multicenter Observational Study of Dental Outcomes in Head and Neck Cancer Patients (OraRad) cohort.

METHODS

Participants were evaluated before RT and at 6, 12, 18, and 24 months after RT. Exposed bone was characterized by location, sequestrum formation, and other associated features. The radiation dose to the affected area was determined, and the history of treatment for exposed bone was recorded.

RESULTS

The study enrolled 572 participants; 35 (6.1%) were diagnosed with incident exposed bone at 6 (47% of reports), 12 (24%), 18 (20%), and 24 months (8%), with 60% being sequestrum and with 7 cases (20%) persisting for >6 months. The average maximum RT dose to the affected area of exposed bone was 5456 cGy (SD, 1768 cGy); the most frequent associated primary RT sites were the oropharynx (42.9%) and oral cavity (31.4%), and 76% of episodes occurred in the mandible. The diagnosis of ORN was confirmed in 18 participants for an incidence rate of 3.1% (18 of 572). Risk factors included pre-RT extractions (P = .008), a higher RT dose (P = .039), and tobacco use (P = .048).

CONCLUSIONS

The 2-year incidence of exposed bone in the OraRad cohort was 6.1%; the incidence of confirmed ORN was 3.1%. Exposed bone after RT for HNC is relatively uncommon and, in most cases, is a short-term complication, not a recurring or persistent one.

Molecular and Cellular Mechanisms of Perineural Invasion in Oral Squamous Cell Carcinoma: Potential Targets for Therapeutic Intervention

Simple Summary

Squamous cell carcinoma is the most common type of oral cavity cancer. It can spread along and invade nerves in a process called perineural invasion. Perineural invasion can increase the chances of tumor recurrence and reduce survival in patients with oral cancer. Understanding how oral cancer interacts with nerves to facilitate perineural invasion is an important area of research. Targeting key events that contribute to perineural invasion in oral cavity cancer may reduce tumor recurrence and improve survival. In this review, we describe the impact of perineural invasion in oral cancer and the mechanisms that contribute to perineural invasion. Highlighting the key events of perineural invasion is important for the identification and testing of novel therapies for oral cancer with perineural invasion.

Abstract

The most common oral cavity cancer is squamous cell carcinoma (SCC), of which perineural invasion (PNI) is a significant prognostic factor associated with decreased survival and an increased rate of locoregional recurrence. In the classical theory of PNI, cancer was believed to invade nerves directly through the path of least resistance in the perineural space; however, more recent evidence suggests that PNI requires reciprocal signaling interactions between tumor cells and nerve components, particularly Schwann cells. Specifically, head and neck SCC can express neurotrophins and neurotrophin receptors that may contribute to cancer migration towards nerves, PNI, and neuritogenesis towards cancer. Through reciprocal signaling, recent studies also suggest that Schwann cells may play an important role in promoting PNI by migrating toward cancer cells, intercalating, and dispersing cancer, and facilitating cancer migration toward nerves. The interactions of neurotrophins with their high affinity receptors is a new area of interest in the development of pharmaceutical therapies for many types of cancer. In this comprehensive review, we discuss diagnosis and treatment of oral cavity SCC, how PNI affects locoregional recurrence and survival, and the impact of adjuvant therapies on tumors with PNI. We also describe the molecular and cellular mechanisms associated with PNI, including the expression of neurotrophins and their receptors, and highlight potential targets for therapeutic intervention for PNI in oral SCC.

Overcoming Nuclear Winter: The Cutting-edge Science of Bone Healing and Regeneration in Irradiated Fields

Background:

The incidence of cancer worldwide is expected to be more than 22 million annually by 2030. Approximately half of these patients will likely require radiation therapy. Although radiotherapy has been shown to improve disease control and increase survivorship, it also results in damage to adjacent healthy tissues, including the bone, which can lead to devastating skeletal complications, such as nonunion, pathologic fractures, and osteoradionecrosis. Pathologic fractures and osteoradionecrosis are ominous complications that can result in large bone and soft tissue defects requiring complex reconstruction. Current clinical management strategies for these conditions are suboptimal and dubious at best. The gold standard in treatment of severe radiation injury is free tissue transfer; however, this requires a large operation that is limited to select candidates.

Methods:

With the goal to expand current treatment options and to assuage the devastating sequelae of radiation injury on surrounding normal tissue, our laboratory has performed years of translational studies aimed at remediating bone healing and regeneration in irradiated fields. Three therapeutics (amifostine, deferoxamine, and adipose-derived stem cells) have demonstrated great promise in promoting healing and regeneration of irradiated bone.

Results:

Amifostine confers prophylactic protection, whereas deferoxamine and adipose-derived stem cells function to remediate postradiation associated injury.

Conclusions:

These prospective therapeutics exploit a mechanism attributed to increasing angiogenesis and ultimately function to protect or restore cellularity, normal cellular function, osteogenesis, and bone healing to nonirradiated metrics. These discoveries may offer innovative treatment alternatives to free tissue transfer with the added benefit of potentially preventing and treating osteoradionecrosis and pathologic fractures

Radiation Can Regulate the Expression of miRNAs Associated with Osteogenesis and Oxidation in Exosomes from Peripheral Blood Plasma

Objectives

Radiotherapy is a common therapy in head and neck tumors, which may cause a side effect radiation bone injury (RBI). Furthermore, it has been investigated that microRNA (miRNA) expression levels were altered after radiotherapy. Exosomes play a role in bone formation as miRNA containers, while radiation affects exosomes composition, secretion, and function. So, our objective is to explore changes in miRNA levels during bone formation after radiotherapy and identify the differentially expressed miRNAs (DE-miRs) in plasma exosomes during the process of osteogenesis related to irradiation.

Materials and Methods

In this study, we analyzed nine samples from three rabbits exposed twice to radiation (15 Gy each) and detected DE-miRs from irradiated plasma exosomes during the process of osteogenesis by RNA sequencing. Further, we identified DE-miRs with significant differences and predicted their target genes via the bioinformatics analysis tools Targetscan v7.2 and miRPathDB v2.0. Finally, we identified radiation-responsive miRNAs and predicted their target genes during osteogenesis.

Results

Taken together, we have identified some DE-miRs in irradiated plasma exosomes, which were involved in several vital signaling pathways related to bone physiology, such as the Wnt pathway, MAPK cascade, and calcium modulating pathway.

Conclusions

We have found that plasma exosomes are one of the ways by which radiation can affect bone metabolism and regeneration. However, the specific mechanisms of how these plasma exosomal miRNAs mediate the osteogenesis pathways must be further investigated. Clinical Relevance. Radiotherapy may cause radiation bone injury, and miRNA expression levels in rabbit plasma exosomes are altered after radiotherapy. High-throughput RNA sequencing can identify the differentially expressed miRNAs in irradiated plasma exosomes during the process of osteogenesis. These findings make sense to develop novel therapeutic strategies for treating radiation-induced bone injury disorders.

Osteomyocutaneous Free Fibula Flap Prevents Osteoradionecrosis and Osteomyelitis in Head and Neck Cancer Reconstruction

BACKGROUND

 Osteoradionecrosis (ORN) is one of the most severe complications of free fibula reconstruction after radiotherapy. The gold standard treatment of osteomyelitis involves extensive debridement, antibiotics, and sufficiently vascularized muscle flap coverage for better circulation. Therefore, we hypothesized that free fibula flap with muscle could decrease the risk of ORN.

METHODS

 This study consisted of 85 patients who underwent reconstruction with free fibula flap in head and neck cancer by a single reconstructive surgeon at Kaohsiung Veterans General Hospital over a period of 19 years (1998-2016). Patients with postoperative adjuvant radiotherapy were included in the study and were grouped by either free fibula osteocutaneous flap or free fibula osteomyocutaneous flap (with flexor hallucis longus muscle), and the incidence of ORN was compared.

RESULTS

 Of the 85 patients, 15 were reconstructed with osteocutaneous fibula flap and 70 were with osteomyocutaneous fibula flap. The rate of ORN or osteomyelitis was significantly lower in the muscle group (18.6%, n = 13/70 vs. 46.7%, n = 7/15, p = 0.020, Chi-square test).

CONCLUSION

 Vascularized muscle transfer increases perfusion of surrounding tissues and the bone flap, thereby decreasing the incidence of osteomyelitis or osteonecrosis.

Risk factors for osteoradionecrosis of the jaw in patients with head and neck squamous cell carcinoma

BACKGROUND

To evaluate factors associated with osteoradionecrosis of the jaw (ORNJ) in patients with head and neck squamous cell carcinoma (HNSCC), focusing on jaw-related dose-volume histogram (DVH) parameters.

METHODS

We retrospectively reviewed the medical records of 616 patients with HNSCC treated with curative-intent or postoperative radiation therapy (RT) during 2008-2018. Patient-related (age, sex, history of smoking or alcohol use, diabetes mellitus, performance status, pre-RT dental evaluation, pre- or post-RT tooth extraction), tumor-related (primary tumor site, T-stage, nodal status), and treatment-related (pre-RT surgery, pre-RT mandible surgery, induction or concurrent chemotherapy, RT technique) variables and DVH parameters (relative volumes of the jaw exposed to doses of 10 Gy-70 Gy [V10-70]) were investigated and compared between patients with and without ORNJ. The Mann-Whitney U test was used to compare RT dose parameters. Univariate and multivariate Cox regression analyses were used to assess factors associated with ORNJ development. Kaplan-Meier analyses were performed for cumulative ORNJ incidence estimation.

RESULTS

Forty-six patients (7.5%) developed ORNJ. The median follow-up duration was 40 (range 3-145) months. The median time to ORNJ development was 27 (range 2-127) months. DVH analysis revealed that V30-V70 values were significantly higher in patients with than in those without ORNJ. In univariate analyses, primary tumor site, pre-RT mandible surgery, post-RT tooth extraction, and V60 > 14% were identified as important factors. In multivariate analyses, V60 > 14% (p = 0.0065) and primary tumor site (p = 0.0059) remained significant. The 3-year cumulative ORNJ incidence rates were 2.5% and 8.6% in patients with V60 ≤ 14% and > 14%, respectively (p < 0.0001), and 9.3% and 1.4% in patients with oropharyngeal or oral cancer and other cancers, respectively (p < 0.0001).

CONCLUSIONS

V60 > 14% and oropharyngeal or oral cancer were found to be independent risk factors for ORNJ. These findings might be useful to minimize ORNJ incidence in HNSCC treated with curative RT.

Osteoradionecrosis: Exposing the Evidence Not the Bone

Osteoradionecrosis is a relatively rare but potentially morbid and costly complication of radiation therapy for head and neck cancer. Multidisciplinary diagnosis and treatment are essential. Despite evidence guiding individual aspects of care for osteoradionecrosis, there is a lack of broad consensus on the overall diagnosis and management of this condition. This study comprehensively reviews the literature, with a focus on the past 10 years, to guide evaluation and treatment.

Tumor subsites and risk of osteoradionecrosis of the jaw in patients with oral cavity cancer: a national-based cohort study

PURPOSE

The association between the tumor subsites of the oral cavity and the risk of osteoradionecrosis of the jaw (ORNJ) remains unclear. We study the correlation between oral cavity tumor subsites and the risk of ORNJ in a nationwide population-based database.

METHODS

We enrolled 16,701 adult patients with oral cavity cancers who were treated with radiotherapy between 2000 and 2013. The subsites of the oral tumor, treatments of oral cavity cancers, and the timing of tooth extraction were examined for their association with ORNJ in oral cancer patients.

RESULTS

903 patients (5.40%) developed ORNJ. Of the relevant variables, pre-RT mandible surgery, tooth extraction either before or after RT, and tumor sites were associated with the risk of ORNJ. The adjusted HRs for ORNJ in the mouth floor, gums, retromolar, and buccal cancer were 2.056 (1.490-2.837), 1.909 (1.552-2.349), 1.683 (1.105-2.562), and 1.303 (1.111-1.528), respectively, compared with the risk of tongue cancer. There was no significant difference in the risk of ORNJ between the pre-RT extraction group, the during-RT extraction group, and the post-RT extraction (less than 6 months) group; the post-RT extraction (more than 6 months) group had a significantly higher risk of ORNJ.

CONCLUSIONS

This study demonstrated that oral cavity tumor subsite is an independent risk factor of ORNJ after RT. Post-RT extraction (less than 6 months) group did not carry a significantly higher risk of ORNJ compared with pre-RT extraction group or during RT extraction group.

Outcomes of microvascular composite reconstruction for mandibular osteoradionecrosis

The aim of this retrospective study was to compare outcomes and reconstruction-related complications in patients receiving a composite free flap reconstruction of the mandible for ORN with those reconstructed for other indications. The records of all patients who underwent composite reconstruction of a mandibular defect at Aintree University Hospital, Liverpool, were reviewed and analysed. Based on radiotherapy exposure and ORN history, the study cohort was divided into three separate case-matched groups. Local wound healing issues were markedly more common in the ORN setting, as was infection and subsequent osteosynthesis plate(s) removal. Free flap survival was similar among all three case-matched groups. Advanced mandibular ORN may be safely and predictably reconstructed with composite free flaps, and that while the rate of local complications is greater than non-irradiated, and non-ORN case-matched controls, the free flap survival rate compares favourably.

Exosome secreted by human gingival fibroblasts in radiation therapy inhibits osteogenic differentiation of bone mesenchymal stem cells by transferring miR-23a

Radiation-induced fibrosis is recently established as a main reason for osteoradionecrosis of the jaw (ORNJ), anti-eradiation fibrosis drugs achieve satisfactory therapeutic effects. However, the molecular mechanism remain to be fully elucidated. In this study, we found the inhibitory effect of irradiation activated gingival fibroblasts on osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs). Moreover, irradiation-activated-fibroblasts significantly increased miR‑23a expression in hBMSCs. Decreased miR‑23a enhanced osteogenic differentiation of BMSCs, and elevated miR‑23a inhibited this process via directly targeting CXCL12. Finally, exosome released from irradiation-activated-fibroblasts inhibited osteogenic differentiation of BMSCs, and these exosome mediated delivery of miR-23a and further regulated miR-23a/CXCL12 axis in hBMSCs. Therefore, our findings suggest that by transferring miR-23a, exosome secreted by human gingival fibroblasts in radiation therapy serves a vital role in osteogenic differentiation of hBMSCs, which may provide novel clinical treatments for ORNJ.

[Concurrent chemoradiotherapy for head neck cancers. Should organs at risk dose constraints be revisited ?]

Concurrent chemoradiotherapy improves the outcome of locally advanced head and neck cancers and the current reference chemotherapy is cisplatin. These results are obtained at the cost of increased toxicities. To limit the risk of toxicity, organ at riskdose constraints have been established starting with 2D radiotherapy, then 3D radiotherapy and intensity-modulated radiotherapy. Regarding grade ≥3 acute toxicities, the scientific literature attests that concurrent chemoradiotherapy significantly increases risks of mucositis and dysphagia. Constraints applied to the oral mucosa volume excluding the planning target volume, the pharyngeal constrictor muscles and the larynx limit this adverse impact. Regarding late toxicity, concurrent chemoradiotherapy increases significantly the risk of postoperative neck fibrosis and hearing loss. However, for some organs at risk, concurrent chemotherapy appears to increase late radiation induced effect, even though the results are less marked (brachial plexus, mandible, pharyngeal constrictor muscles, parotid gland). This additional adverse impact of concomitant chemotherapy may be notable only when organs at risk receive less than their usual dose thresholds and this would be vanished when those thresholds are exceeded as seems to be the situation for the parotid glands. Until the availability of more robust data, it seems appropriate to apply the principle of delivering dose to organs at risk as low as reasonably achievable.

Preradiation tooth extraction and jaw osteoradionecrosis: Nationwide population-based retrospective study in Taiwan

OBJECTIVE

Radiotherapy (RT) for head and neck cancer (HNC) within 7 days of tooth extraction is contraindicated because it may increase the risk of osteoradionecrosis of the jaw (ORNJ). However, delayed RT could compromise survival in patients with HNC. By using a national healthcare database, we reviewed the contraindications and analysed other risk factors for ORNJ.

DESIGN

A retrospective cohort study.

SETTING

By using Taiwan's National Health Insurance Research Database, 5,062 HNC patients with at least one tooth extraction 1-21 days before the first RT day (index day) and without any extractions during or after RT from 2000 to 2013 were included. The patients were divided into two groups according to the time of tooth extraction before the index day: 1-7 days and 8-21 days.

PARTICIPANTS

Taiwanese patients with head and neck cancer.

MAIN OUTCOMES MEASURE

Univariate and multivariate Cox proportional hazard regression models were used to evaluate the risk factors of ORNJ.

RESULTS

The overall incidence of ORNJ in the included patients was 1.03% (mean follow-up duration, 4.07 ± 3.01 years; range, 1.00-13.99 years). Tooth extraction within 7 days before RT was not associated with increased ORNJ risk (hazard ratio [HR] =0.734; P = .312). Significant risk factors for ORNJ included oral cancer (adjusted HR = 3.961), tumour excision surgery within 3 months before RT (adjusted HR = 3.488) and mandibulectomy within 3 months before RT (adjusted HR = 5.985; all P < .001).

CONCLUSION

In a mean follow-up of 4 years, tooth extraction within 7 days before RT for HNC treatment did not increase the ORNJ risk compared with tooth extraction 7-21 days before RT.

External fixation greatly improves outcomes in the surgical treatment of osteoradionecrosis of the jaws without affecting quality of life: a five-year retrospective study

Osteoradionecrosis of the jaw can be treated using both conservative treatment and surgery. External fixation may be used to bridge large resection defects after sequestrectomy for stabilisation and before secondary mandibular reconstruction. We designed a retrospective analysis of 70 patients with osteoradionecrosis treated between the years 2014 and 2018, and found that the use of external fixation greatly improves their outcomes. Patients were grouped according to Notani's classification: those who had Notani I disease were treated surgically but without external fixation; and those with Notani II and Notani III disease were eligible for external fixation. In those with Notani II disease, there was a significant reduction in the number of pathological fractures that occurred with external fixation. In those with Notani III disease, the success rate of primary sequestrectomy was only 1:14; however, those treated with external fixation all successfully healed after their first operation. It was hypothesised that although external fixation would improve outcome, it would come at a detriment to their quality of life (QoL). However, in a subset of these patients, we showed that in addition to increasing successful healing, patients' QoL with the external fixator was no worse than when they had an active osteonecrotic lesion. The treatment of osteoradionecrosis is cumbersome and advanced stages are associated with more complications. The use of an external fixator significantly reduces the probability of pathological fractures and increases the rate of successful healing in patients after mandibular resection. It does this without greatly interfering with patients' lives, while improving their condition sufficiently to allow for subsequent mandibular reconstruction.

Dental prevention of maxillo-mandibular osteoradionecrosis: A ten-year retrospective study

INTRODUCTION

Osteoradionecrosis (ORN) remains a frequent complication of radiotherapy in head and neck cancer. As ORN management is often complex, it is essential to focus on its prevention, mainly by dental prophylaxis. The objectives of this study were to evaluate a dental preventive approach based on ORN data and to highlight individual risk factors statistically associated with time-to-ORN.

MATERIALS AND METHODS

A retrospective study (January 2004-December 2013) included 415 patients with head and neck cancer who received radiotherapy in their treatment with at least 50 Grays on maxillo-mandibular bones. Pre-radiotherapy dental assessment (clinical and radiological) and prevention (with standardised extraction protocol) were performed.

RESULTS

The ORN rate was 7.5%, with a dental origin in 35.5% of cases, mainly represented by dental infection in exclusive mandibular locations. More than 90% of patients were partially or completely dentate, and more than 70% had poor oral hygiene. Dental extractions were performed in 67.9% of patients before radiotherapy and in 42.9% after radiotherapy. Statistically significant risk factors associated with time-to-ORN were addictions (tobacco and alcohol), diabetes, oropharyngeal tumour location, combination of surgery followed by radiotherapy and post-radiotherapy dental extractions.

DISCUSSION AND CONCLUSION

Considering that ORN implies severe disabilities and complex management, the rate of 7.5% is unacceptable. A better dental prevention could reduce this rate by one-third. Dental extractions could be systematic in high-dose irradiation mandibular areas in patients presenting with poor oral hygiene and/or statistically significant risk factors for the occurrence of ORN. Moreover, favourable oral condition after radiotherapy should be maintained.

Risk assessment for osteoradionecrosis of the jaws in patients with head and neck cancer

Objectives

To identify the potential risk factors for the occurrence of osteoradionecrosis (ORN) of the jaws among patients who have been treated with radiotherapy for head and neck malignancy.

Methods

The study comprised of 231 patients treated with radiotherapy for head and neck malignancy at a tertiary referral center. The following details were recorded for each patient: age, gender, histopathological diagnosis, clinical staging, tumor site, treatment modality, radiation dose, radiation field, number of fractions, type of accelerator used, radiation area and duration of follow-up. Patient’s tobacco, alcohol habit history, and history of extraction of teeth before/during/after radiotherapy were also noted.

Results

Thirteen patients had osteoradionecrosis (frequency 5.62%). Among the radiotherapy variables assessed, increased radiation area was found to be significantly associated with the occurrence of osteoradionecrosis. Among the 13 ORN cases, 10 (76.9%) had a history of tobacco consumption, 8 (61.5%) had a time interval between radiotherapy and occurrence of ORN of less than 1-year duration.

Conclusions

We found a low cumulative incidence of osteoradionecrosis and a tendency to occur within a year of starting radiotherapy. Patients of older age, those with a prior tobacco habit may be considered more liable to develop osteoradionecrosis. A larger radiation field may also put patients at hazard for developing osteoradionecrosis.

Chinese expert group consensus on diagnosis and clinical management of osteoradionecrosis of the mandible

Osteoradionecrosis of the mandible (MORN) is one of the most devastating complications caused by radiation therapy in the head and neck region. It is characterized by infection and chronic necrosis of the mandible as the main manifestation. Clinically, MORN-related symptoms include swelling, pain, dysphagia, trismus, masticatory or speech disorders, refractory orocutaneous fistula, bone exposure, and even pathological fracture. MORN has become a challenging clinical problem for oral and maxillofacial surgeons to deal with, but thus far, this problem has not been solved due to the lack of widely accepted treatment algorithms or guidelines. Because of the nonexistence of standardized treatment criteria, most clinical treatment against MORN nowadays is largely based on controversial empirical understandings, while recommendations on post-therapeutic evaluations are scarce. Therefore, to further unify and standardize the diagnosis and treatment of MORN, to decrease the huge waste of medical resources, and ultimately, to improve the wellbeing of the patients, the Chinese Society of Oral and Maxillofacial Surgery (CSOMS) convened an expert panel specialized in MORN from 16 domestic medical colleges and affiliated hospitals to discuss the spectrum of diagnosis and and formulate treatment. In addition, consensus recommendations were also revised with a comprehensive literature review of the previous treatment experiences and research pearls. This 'expert consensus statement on diagnosis and clinical management of MORN' is for clinical reference.

Effect of Radiation on DCE-MRI Pharmacokinetic Parameters in a Rabbit Model of Compromised Maxillofacial Wound Healing: A Pilot Study

PURPOSE

Osteoradionecrosis (ORN), a potentially debilitating complication of maxillofacial radiation, continues to present a challenging clinical scenario, with limited treatment options that often fail. Translational animal models that can accurately mimic the human characteristics of the condition are lacking. In the present pilot study, we aimed to characterize the effects of radiation on the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) pharmacokinetic parameters in a rabbit model of compromised maxillofacial wound healing to determine its potential as a translational model of ORN.

MATERIALS AND METHODS

An experimental group underwent fractionated radiation of the mandible totaling 36 Gy. At 4 weeks after irradiation, the experimental and control groups (n = 8 rabbits each) underwent a surgical procedure to create a critical size defect in the mandibular bone. DCE-MRI scans were acquired 1 week after arrival (baseline; time point 1), 4 weeks after completion of irradiation in the experimental group (just before surgery, time point 2), and 4 weeks after surgery (time point 3).

RESULTS

No differences in the analyzed DCE-MRI parameters were noted within the experimental or control group between the baseline values (time point 1) and those after irradiation (time point 2). The whole blood volume fraction (v_b) in the experimental group was increased compared with that in the control group after irradiation (time point 2; P < .05). After surgery (time point 3), both the forward flux rate of contrast from blood plasma and the extracellular extravascular space and the v_b were increased in the control group compared with the experimental group (P < .05).

CONCLUSIONS

The results of the present study suggest that DCE-MRI of a rabbit model of compromised maxillofacial wound healing could reflect the DCE-MRI characteristics of human patients with ORN and those at risk of developing the condition. Future studies will focus on further characterization of this rabbit model as a translational preclinical model of ORN.

Lumbar vertebral osteoradionecrosis: a rare case report with 10-year follow-up and brief literature review

Background

Osteoradionecrosis (ORN) is a complication that occurs after radiotherapy for head or neck malignancies. ORN of the spine is rare, with only few cases affecting the cervical spine reported to date. To our knowledge, no case of lumbar ORN has been reported. We report a rare case of ORN in the lumbar spine that occurred 2 years after radiotherapy and perform a literature review.

Case presentation

We present a case of lumbar ORN that occurred 2 years after radiotherapy for gallbladder carcinoma. The patient was successfully treated conservatively and followed up for > 10 years.

Conclusions

ORN of the spine is a rare complication of radiotherapy. Spinal ORN is clinically described as a chronic disease with a slow onset. The most common presenting symptom of spinal ORN is pain. However, as ORN progresses, spinal kyphosis and instability can lead to neurological compression and thus to induced myelopathy or radiculopathy. Treatment of spinal ORN is comprehensive, including orthosis, medication, hyperbaric oxygen therapy, surgery, and new treatment combinations of pentoxifylline and tocopherol. The surgical rate for spinal ORN is relatively high.