Mandibular Osteoradionecrosis

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.

[Prevention, diagnosis and management of osteoradionecrosis: Where do we stand?]

Osteoradionecrosis (ORN) is a late secondary iatrogenic complication of external radiotherapy for cancers of the upper aero-digestive tract. Despite the systematization of intensity-modulated radiotherapy and its potential for preserving salivary secretion and limiting the dose delivered to the supporting bone, ORN remains a feared and frequent complication. The objective of this literature review was to provide an overview of the management of ORN and to determine the key points that would make it possible to improve patient care. The diagnosis of ORN requires to eliminate tumor recurrence then is based on clinical arguments and imaging by CT or Cone Beam evolving in a chronic mode (more than 3-6 months). The harmonization of its classifications aims to offer comprehensive and multidisciplinary care as early as possible. Primary prevention is based on pre-therapeutic oral and dental preparation, then associated with fluoroprophylaxis if salivary recovery is insufficient and requires supervision of invasive dental care and prosthetic rehabilitation. Semi-automatic contouring tools make it possible to identify doses delivered to dental sectors and guide dental care with personalized dosimetric mapping. Conservative medical treatment is offered at an early stage where innovative medical treatments, highlighted by early studies, could be of interest in the future. In the event of advanced ORN, a non-conservative treatment is then proposed and frequently consists of interruptive mandibulectomy associated with reconstruction by bony free flap, the conditions of implantation remaining to be defined with the support of prospective clinical trials.

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.

The Role of Dental Practitioners in the Management of Oncology Patients: The Head and Neck Radiation Oncology Patient and the Medical Oncology Patient

This narrative review addresses the role of a dentist in the management of oncology patients, highlighting the oral complications that arise in head and neck radiation oncology patients and medical oncology patients. The prevention and management of these complications are discussed.

Dental Care in Head and Neck Cancer Patients Undergoing Radiotherapy

External beam radiotherapy is an integral part of the management of head and neck cancer. Radiotherapy for head and neck cancer lead to many treatment-related toxicities, including a wide range of dental morbidities. These complications depend on the various patient and treatment-related factors. Patients with poor oral hygiene, pre-existing periodontal disease, and the conventional mode of radiotherapy delivery are major factors leading to acute and severe late dental problems. Most of the complications are preventable with proper oral and dental care before, during and after radiotherapy. Pre radiotherapy dental evaluation to diagnose patients with potential risk and timely intervention can reduce long-term morbidities like carries, osteoradionecrosis, etc., thereby improving patients' quality of life. This article highlights the various aspects of dental care and management in head neck cancer patients before, during and after radiation therapy.

Outcomes after definitive surgery for mandibular osteoradionecrosis

OBJECTIVES

To analyze charges, complications, survival, and functional outcomes for definitive surgery of mandibular osteoradionecrosis (ORN).

MATERIALS AND METHODS

Retrospective analysis of 76 patients who underwent segmental mandibulectomy with reconstruction from 2000 to 2009.

RESULTS

Complications occurred in 49 (65%) patients and were associated with preoperative drainage (odds ratio [OR] 4.40, 95% confidence interval [CI] 1.01-19.27). The adjusted median charge was $343 000, and higher charges were associated with double flap reconstruction (OR 8.15, 95% CI 2.19-30.29) and smoking (OR 5.91, 95% CI 1.69-20.72). Improved swallow was associated with age <67 years (OR 3.76, 95% CI 1.16-12.17) and preoperative swallow (OR 3.42, 95% CI 1.23-9.51). Five-year ORN-recurrence-free survival was 93% while overall survival was 63% and associated with pulmonary disease (HR [hazard ratio] 3.57, 95% CI 1.43-8.94).

CONCLUSIONS

Although recurrence of ORN is rare, surgical complications are common and charges are high. Poorer outcomes and higher charges are associated with preoperative factors.

Utilising radiotherapy dose to guide 3D surgical reconstructions for mandibular osteoradionecrosis

Introduction:

Following radiotherapy for head and neck cancer, a proportion of patients present with mandibular osteoradionecrosis (ORN). Reported incidence and presentation of ORN vary widely, although often initiated by trauma with radiotherapy being the biggest risk factor. Evolved disease requires surgery, mandibular resection and reconstruction. As ORN is a progressive disease, it can manifest beyond resected volumes, compromising surgery. To minimise surgical failures, we present incorporating radiotherapy dose into the surgical design and decision processes—dose guided surgery (DGS).

Method:

Five mandibular ORN patients, referred for resection and reconstruction, underwent DGS—mandible visualised on diagnostic CT, propagated to radiotherapy planning CT, radiotherapy dose displayed on the mandible, high-risk mandible converted to stl files and incorporated in the surgical design.

Results:

DGS ensures high-dose, high-risk ORN mandible is resected, and fixation devices are located in low-dose, low-risk areas.

Conclusions:

DGS represents a potential new standard of care for patients presenting with mandibular ORN post-radiotherapy. Formal follow-up of this small cohort is ongoing although DSG is anticipated to increase the success rate of this high cost, high burden procedure compared to surgery designed on clinical and radiological assessments alone.

Advances in Organ Preservation for Laryngeal Cancer

OPINION STATEMENT

At the University of Wisconsin, all treatment of head and neck cancer patients begins with discussion at our multi-disciplinary tumor board. Most patients with T4 disease, with existing laryngeal dysfunction, considered unlikely to complete definitive CRT or who have a high risk of persistent aspiration after non-operative management undergo total laryngectomy. A laryngeal sparing approach is attempted on most other patients. Radiotherapy is delivered over 6.5 weeks, preferably with concurrent weekly cisplatin. If the patient is hesitant of chemotherapy or has contraindications to cisplatin, concurrent cetuximab may be offered. Patients treated with RT alone are often treated to the same dose, but via an accelerated schedule by adding a 6th fraction per week. The 6th fraction is given by delivering two treatments at least 6 h apart on a weekday of the patient's choosing. We consider the following to be major risk factors for clinically significant weight loss during treatment: a 10% or greater loss of weight in the 6 months prior to starting treatment, delivery of concurrent cisplatin, and treatment of the bilateral neck with radiation. Patients who have 2-3 of these characteristics are often given gastrostomy tubes prophylactically. Patients are seen 2 weeks after completion of therapy, and then every 3 months after completion for 2 years. A CT neck and PET-CT are performed at the first 3-month visit. They are seen twice in year three, and then yearly until years 5-7. At each of these visits, we have a low threshold to present the patient at our multidisciplinary tumor board for consideration of salvage laryngectomy if there are signs of progression.

Radiation necrosis of the bone, cartilage or cervical soft-tissues following definitive high-precision radio(chemo)therapy for head-neck cancer: uncommon and under-reported phenomenon

Background

The impact of modern high-precision conformal techniques on rare but highly morbid late complications of head and neck radiotherapy, such as necrosis of the bone, cartilage or soft-tissues, is not well described.

Method

Medical records of head and neck cancer patients treated in prospective clinical trials of definitive high-precision radiotherapy were reviewed retrospectively to identify patients with necrosis.

Results

Twelve of 290 patients (4.1 per cent) developed radiotherapy necrosis at a median interval of 4.5 months. There was no significant difference in baseline demographic (age, gender), disease (primary site, stage) and treatment characteristics (radiotherapy technique, total dose, fractionation) of patients developing radiotherapy necrosis versus those without necrosis. Initial management included antibiotics or anti-inflammatory agents, tissue debridement and tracheostomy as appropriate followed by hyperbaric oxygen therapy and resective surgery for persistent symptoms in selected patients.

Conclusion

Multidisciplinary management is essential for the prevention, early diagnosis and successful treatment of radiotherapy necrosis of bone, cartilage or cervical soft tissues.

Platelet-rich fibrin as a treatment option for osteoradionecrosis: A literature review

The aim of this review is to establish the usefulness and effectiveness of using platelet-rich fibrin (PRF) in the treatment of osteoradionecrosis (ORN) lesions. A review of the literature was performed using keywords through the PubMed-Medline and Cochrane Library search engine. Inclusion criteria were: (1) original publication in either the French or the English language, (2) studies conducted in humans, (3) presence of ORN lesions following head and neck radiotherapy (RT), (4) use of PRF or derivates in the treatment of ORN lesions, (5) clinical variables and outcomes mentioned in the study. Overall, four case reports were retained. Two publications were removed from the initial seven results after application of the inclusion criteria. A recent randomised clinical trial was not considered since the group analysed the effectiveness of leukocyte-enriched Plasmas-Rich-Fibrin (LPRF) in preventing ORN, but not in treating it. Therefore, four publications were retained for analysis. Results suggest that using PRF as an adjunct to surgical therapy is beneficial in treating ORN lesions although no controlled studies were found. Therefore, additional controlled clinical studies are warranted to better define the effectiveness and recommendation of this approach.

Computed Tomography Radiomics Kinetics as Early Imaging Correlates of Osteoradionecrosis in Oropharyngeal Cancer Patients

Osteoradionecrosis (ORN) is a major side-effect of radiation therapy in oropharyngeal cancer (OPC) patients. In this study, we demonstrate that early prediction of ORN is possible by analyzing the temporal evolution of mandibular subvolumes receiving radiation. For our analysis, we use computed tomography (CT) scans from 21 OPC patients treated with Intensity Modulated Radiation Therapy (IMRT) with subsequent radiographically-proven ≥ grade II ORN, at three different time points: pre-IMRT, 2-months, and 6-months post-IMRT. For each patient, radiomic features were extracted from a mandibular subvolume that developed ORN and a control subvolume that received the same dose but did not develop ORN. We used a Multivariate Functional Principal Component Analysis (MFPCA) approach to characterize the temporal trajectories of these features. The proposed MFPCA model performs the best at classifying ORN vs. Control subvolumes with an area under curve (AUC) = 0.74 [95% confidence interval (C.I.): 0.61–0.90], significantly outperforming existing approaches such as a pre-IMRT features model or a delta model based on changes at intermediate time points, i.e., at 2- and 6-month follow-up. This suggests that temporal trajectories of radiomics features derived from sequential pre- and post-RT CT scans can provide markers that are correlates of RT-induced mandibular injury, and consequently aid in earlier management of ORN.

[Predictive factors for mandibular osteoradionecrosis after irradiation of head and neck cancers]

The identification of the different risk factors for mandibular osteoradionecrosis (ORN) must be done before and after the management of patients with head and neck cancer. Various clinical criteria for this severe radiation-induced complication are related to the patient (intrinsic radiosensitivity, malnutrition associated with thin weight loss, active smoking intoxication, microcapillary involvement, precarious oral status, hyposalivation) and/or related to the disease (oral cavity, large tumor size, tumor mandibular invasion). Therapeutic risk factors are also associated with a higher risk of ORN (primary tumor surgery, concomitant radio-chemotherapy, post-irradiation dental avulsion, preventive non-observance with the absence of stomatological follow-up and daily installation of gutters fluoride and, non-observance curative healing treatments). Finally, various dosimetric studies have specified the parameters in order to target the dose values distributed in the mandible, which increases the risk of ORN. An mean mandibular dose greater than 48-54Gy and high percentages of mandibular volume receiving 40 to 60Gy appear to be discriminating in the risk of developing an ORN.

Hypomagnesemia and incidence of osteoradionecrosis in patients with head and neck cancers

BACKGROUND

We aimed to determine whether hypomagnesemia predicts osteoradionecrosis development in patients with squamous cell carcinoma of the oropharynx and oral cavity who received platinum-based concurrent chemoradiation with or without induction therapy.

METHODS

We reviewed data from patients with head and neck cancers who had undergone chemoradiation with weekly cisplatin/carboplatin between January 1, 2010 and December 31, 2014 at our institution. Pathologic features, laboratory test results, disease stage, and social histories were recorded. The association between hypomagnesemia and osteoradionecrosis was analyzed controlling for known confounding factors.

RESULTS

Hypomagnesemia during cancer treatment was associated with osteoradionecrosis development (HR = 2.72, P = .037) independent of total radiation dose (HR = 1.07, P = .260) and smoking history (HR = 2.05, P = .056) among the patients who received platinum-based induction chemotherapy followed by concurrent chemoradiation.

CONCLUSIONS

Hypomagnesemia was predictive of the development of osteoradionecrosis in patients with cancers of the oropharynx and oral cavity receiving platinum-based induction followed by concurrent chemoradiation.

Bone Regeneration Effect of Hyperbaric Oxygen Therapy Duration on Calvarial Defects in Irradiated Rats

Objective

In this study, we evaluated changes in bone remodeling in an irradiated rat calvarial defect model according to duration of hyperbaric oxygen therapy.

Materials and Methods

The 28 rats were divided into four groups. Radiation of 12 Gy was applied to the skull, and 5-mm critical size defects were formed on both sides of the skull. Bone grafts were applied to one side of formed defects. From the day after surgery, HBO was applied for 0, 1, and 3 weeks. At 6 weeks after bone graft, experimental sites were removed and analyzed for radiography, histology, and histomorphometry.

Results

Micro-CT analysis showed a significant increase in new bone volume in the HBO-3 group, with or without bone graft. When bone grafting was performed, BV, BS, and BS/TV all significantly increased. Histomorphometric analysis showed significant increases in %NBA and %BVN in the HBO-1 and HBO-3 groups, regardless of bone graft.

Conclusion

Hyperbaric oxygen therapy was effective for bone regeneration with only 1 week of treatment.

Modern management of osteoradionecrosis

PURPOSE OF REVIEW

Despite recent advances in radiotherapy, osteoradionecrosis (ORN) remains a common and difficult complication of radiation therapy in head and neck cancer patients. Available treatment options are complementary to its complex pathophysiology and the currently available theories of ORN development. The efficacy of hyperbaric oxygen therapy has recently been questioned, and therapies targeting the fibroatrophic process have become a focus of ORN treatment. The objective of this review is to evaluate the literature regarding ORN of the mandible, with a focus on available treatment options.

RECENT FINDINGS

The recently proposed fibroatrophic theory has challenged the traditional hypovascular-hypoxic-hypocellular theory as the mechanism of ORN. Medical management targeting this fibroatrophic process offers promising results, but has yet to be confirmed with robust clinical trials. The routine use of hyperbaric oxygen therapy is not substantiated in the literature, but may be justified for select patients. Systemic steroids may also have a role, though data are limited.

SUMMARY

The fibroatrophic process has gained acceptance as a main mechanism of ORN. No gold standard treatment or consensus guidelines exist, though a combination of therapeutic strategies should be considered, taking into account the severity of disease and individual patient characteristics.

Teriparatide therapy for severe, refractory osteoradionecrosis of the jaw

Although osteoradionecrosis (ORN) is a serious complication of craniofacial radiotherapy, the current management methods remain suboptimal. Teriparatide (TPTD), a recombinant human parathyroid hormone (1-34), has shown beneficial effects on osseous regeneration in medication-related osteonecrosis of the jaw or periodontitis. However, TPTD therapy in irradiated bones has not been indicated yet because of the theoretical risk of osteosarcoma seen in rat models. Hence, we first report here two patients with tongue cancer with late-emerging ORN who were successfully treated with TPTD for 4-6 months with serum calcium and vitamin D supplementation. In contrast to the usual progress of ORN, the bone defect regenerated well and bone turnover markers including serum C-terminal telopeptide of type 1 collagen and osteocalcin were restored with TPTD therapy. Our experience might suggest that TPTD therapy with careful monitoring can provide an effective treatment option for patients with ORN in select refractory cases, with the benefits outweighing the potential risks.

Osteoradionecrosis of the jaws: definition, epidemiology, staging and clinical and radiological findings. A concise review

Osteoradionecrosis (ORN) of the jaws is a pernicious complication of radiation therapy for head and neck tumours. This article aims to provide an update on data related to the definition, epidemiology, staging, and clinical and radiological findings of ORN of the jaws. Using certain keywords, an electronic search was conducted spanning the period from January 1922 to April 2014 to identify the available related investigations. Pooled data were then analysed. ORN is described as exposed irradiated bone that fails to heal over a period of 3 months without evidence of persisting or recurrent tumour. The prevalence of ORN varies in the literature. Several staging or scoring systems of ORN have been proposed. Clinical findings include ulceration or necrosis of the mucosa with exposure of necrotic bone. Radiological findings are not evident in the early stages of ORN. Furthermore ORN may not be apparent in imaging even when the disease is advanced. Taking into account the severity of ORN and the difficulties in diagnosing it early and accurately, the clinician should be aware of this complex entity in order to prevent its appearance or the development of more severe complications.

Risk factors for and the role of dental extractions in osteoradionecrosis of the jaws: A national-based cohort study

BACKGROUND

The purpose of this study was to investigate the risk factors, especially the use of certain drugs and the dental procedures, for osteoradionecrosis of the jaw (ORNJ) in patients with head and neck cancer undergoing irradiation as their primary treatment.

METHODS

The cohort was composed of 23,527 patients with head and neck cancer. Cox proportional hazard models were used for risk factors analysis.

RESULTS

The overall incidence of ORNJ is 3.93 per 100 person-years. Buccal cancer carried the highest ORNJ risk. The use of steroids had a protective effect. Preradiotherapy extraction posed no excess risk, whereas postradiotherapy extraction was associated with gradually increased risk of ORNJ over time that peaked at 4 to 5 years.

CONCLUSION

ORNJ warrants life-long attention for head and neck cancer survivors. The present study strongly confirms the role of preirradiation dental extractions. Meanwhile, efforts should be made to prevent posttreatment extractions, especially in the first posttreatment 4 years. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1313-1321, 2017.

Three-dimensional morphological changes of the temporomandibular joint and functional effects after mandibulotomy

BACKGROUND

The midline and paramedian mandibulotomy are surgical procedures that divide the mandibular bone into two halves and disconnects the condylar heads of the TMJ from each other. This study aimed to prospectively evaluate the temporomandibular joint (TMJ) functional and morphological changes after mandibulotomy using a reconstructed 3D models of the TMJ.

METHODS

Sixteen adult patients diagnosed with oral and oropharyngeal tumors with planned surgical mandibulotomy (test group, 9 patients) or transoral (control group, seven patients) treatments were included in the study. MRI and CBCT images were obtained immediately preceeding surgery and 6-8 weeks after surgery. Using the MRI-CBCT registered images, TMJ tissues were segmented at the two occasions by the same operator and 3D models were reconstructed for morphological assessment. Changes across time were measured using the volume overlap and Hausdorff distance of the disc and condyle 3D models. Disc-condyle relationship was measured using point-based and color map analysis. To assess the early functional changes, the Jaw function limitation scale (JFLS) and the maximum mouth opening were measured. Two-sample Hotelling T² t-test was performed to determine the significance of the morphological and clinical outcomes' differences between the two groups.

RESULTS

The two-sample Hotelling T² t-test showed significant differences (T² (df1,df2) = 0.97 (5,26), p <0.01) between the mean values of all outcomes among the 2 groups. The change in disc displacement was significantly different between the two groups (p <0.05). However, the condylar displacement was not significantly different between the two groups (p =0.3). The average of the JFLS score was five times larger after mandibulotomy, and was 2 times larger after transoral surgery (p < 0.01). Patients showed decrease in the average of the maximum interincisal mouth opening by 11 mm after mandibulotomy, and by 5.4 mm after transoral surgery.

CONCLUSION

The quantitative assessment of the TMJ showed minimal changes of the condylar position and variable degrees of articular disc displacement associated with the paramedian split mandibulotomy. As well, limited jaw functions and vertical mouth opening were noticed more in the mandibultomy group compared to the transoral group in 6- weeks after surgery.

Dental Prophylaxis and Osteoradionecrosis: A Population-Based Study

The aim of this study was to investigate the association of different dental prophylactic modalities and osteoradionecrosis (ORN) and determine the risk of ORN under different timing periods of scaling, with the use chlorhexidine mouth rinse after surgery and with different strategies of fluoride gel application in head and neck cancer (HNC) participants. A cohort of 18,231 HNC participants, including 941 ORN patients and 17,290 matched control cases, were enrolled from a Longitudinal Health Insurance Database for Catastrophic Illness Patients (LHID-CIP) in Taiwan. Based on different dental prophylactic modalities before radiotherapy, including chlorhexidine mouth rinse, scaling, and fluoride gel, all HNC subjects were stratified into different groups. The Cox proportional hazard regression was used to compare ORN incidences under different dental prophylactic modalities. The results revealed that scaling and chlorhexidine mouth rinse were significantly related to ORN risk ( P = 0.004 and P < 0.0001). Chlorhexidine mouth rinse was highly correlated to ORN occurrence (hazard ratio [HR], 1.83–2.66), as exposure increased the risk by 2.43-fold among oral cancer patients, regardless of whether they had received major oral surgery or not. Oral cancer patients receiving scaling within 2 wk before radiotherapy increased their incidence of ORN by 1.28-fold compared with patients who had not undergone scaling within 6 mo. There is no significance of fluoride application for dental prophylaxis in increasing ORN occurrence. In conclusion, dental prophylaxis before radiotherapy is strongly correlated to ORN in HNC patients. Chlorhexidine exposure and dental scaling within 2 wk before radiotherapy is significantly related to ORN risk, especially in oral cancer patients. The use of 1.1% NaF topical application did not significantly increase the risk of ORN in HNC patients. An optimal dental prophylaxis protocol to reduce ORN should concern cancer location, cautious prescription of chlorhexidine mouth rinse, and proper timing of scaling.

The prevalence and risk factors associated with osteoradionecrosis of the jaw in oral and oropharyngeal cancer patients treated with intensity-modulated radiation therapy (IMRT): The Memorial Sloan Kettering Cancer Center experience

OBJECTIVE

To determine the prevalence and correlation of various risk factors [radiation dose, periodontal status, alcohol and smoking] to the development of osteoradionecrosis (ORN).

PATIENTS AND METHODS

The records of 1023 patients treated with IMRT for oral cavity cancer (OCC) and oropharyngeal cancer (OPC) between 2004 and 2013 were retrospectively reviewed to identify patients who developed ORN. Fisher exact tests were used to analyze patient characteristics between ORN patients with OCC and OPC. Paired Wilcoxon tests were used to compare the dose volumes to the ORN and contralateral non-ORN sites. To evaluate an association between ORN and risk factors, a case-control comparison was performed. One to 2 ORN-free patients were selected to match each ORN patient by gender, tumor site and size. General estimation equations models were used to compare the risk factors in ORN cases and matched controls.

RESULTS

44 (4.3%) patients developed ORN during a median follow-up time of 52.5months. In 82% of patients, ORN occurred spontaneously. Patients with OPC are prone to develop ORN earlier compared to patients with OCC (P=0.03). OPC patients received a higher Dmax compared to OCC patients (P=0.01). In the matched case-control analysis the significant risk factors on univariate analysis were poor periodontal status, history of alcohol use and radiation dose (P=0.03, 0.002 and 0.009, respectively) and on multivariate analysis were alcohol use and radiation dose (P=0.004 and 0.026, respectively).

CONCLUSION

In our study, higher radiation dose, poor periodontal status and alcohol use are significantly related to the risk of developing ORN.

Approaches for building bioactive elements into synthetic scaffolds for bone tissue engineering

Bone tissue engineering (BTE) is emerging as a possible solution for regeneration of bone in a number of applications. For effective utilization, BTE scaffolds often need modifications to impart biological cues that drive diverse cellular functions such as adhesion, migration, survival, proliferation, differentiation, and biomineralization. This review provides an outline of various approaches for building bioactive elements into synthetic scaffolds for BTE and classifies them broadly under two distinct schemes; namely, the top-down approach and the bottom-up approach. Synthetic and natural routes for top-down approaches to production of bioactive constructs for BTE, such as generation of scaffold-extracellular matrix (ECM) hybrid constructs or decellularized and demineralized scaffolds, are provided. Similarly, traditional scaffold-based bottom-up approaches, including growth factor immobilization or peptide-tethered scaffolds, are provided. Finally, a brief overview of emerging bottom-up approaches for generating biologically active constructs for BTE is given. A discussion of the key areas for further investigation, challenges, and opportunities is also presented.

Osteoradionecrosis and intensity modulated radiation therapy: An overview

Osteoradionecrosis (ORN) is an ongoing topic, especially about its definition, pathogenesis, staging system and management algorithm. But what about its real incidence in intensity modulated radiotherapy (IMRT) era? This paper discusses the mandible in radiation therapy planning as organ at risk and reviews the literature for evidence of radiation damage, discussing likely dose constraints and the use of IMRT to reduce radiation dose to this structure. PubMed search was performed.

Treatment outcome of ion beam therapy in eight patients with head and neck cancers

Ion beam therapy has enabled us to treat formerly untreatable malignant tumors. The aim of the present study was to investigate the long-term follow-up course of patients with head and neck cancers who received ion beam therapy. The subjects were 8 patients (3 men and 5 women aged 43-78 years) with head and neck cancers who visited our department from 2006 to 2015 and received ion beam therapy. Six patients received carbon ion beam therapy, and the other two patients received proton beam therapy. The medical records of the patients were retrospectively analyzed. The primary site was the nasal and paranasal sinuses in six cases, nasopharynx in one case, and external auditory canal in one case. The histological type was olfactory neuroblastoma, malignant melanoma, and adenoid cystic carcinoma in two cases each, and chondrosarcoma and squamous cell carcinoma in one case each. The exposure dose ranged from 64 to 70.4 GyE. The average follow-up period was 42.0 months. Early adverse events were generally mild, and complete therapeutic response was obtained in all cases. However, five patients developed severe late complications including craniospinal dissemination, osteoradionecrosis of the maxilla and skull base, brain necrosis, and loss of eyesight. Three patients died of distant metastasis, local recurrence and/or brain necrosis within 2 years, and four patients have been surviving with distant metastasis or severe late complications. Ion beam therapy exhibits outstanding antitumor effects, but the severe late complications of the therapy must also be recognized.

Recurrent Malignancy in Osteoradionecrosis Specimen

PURPOSE

Osteoradionecrosis (ORN) is a well-known complication of head and neck radiation therapy. Statistically, the mandible is the most commonly affected site. The incidental finding of malignancy in the resection specimen has been documented but is somewhat rare. The aim of this review is to investigate the presence of recurrent carcinoma and sarcoma or new primary malignancies in resection specimens previously diagnosed and treated as ORN.

PATIENTS AND METHODS

This study is a retrospective case series. We conducted a chart review of all cases managed at the University of Miami Miller School of Medicine/Jackson Memorial Hospital. The inclusion criteria included a history of head and neck carcinoma treated with radiation of at least 6,000 cGy; clinical diagnosis of ORN; and surgical intervention with osseous resection for treatment of ORN. The study endpoint measured included microscopic evidence of malignancy in the resected ORN specimen. Additional data collected included gender, age, and type of primary pathology.

RESULTS

A total of 564 patients met the inclusion criteria. Of these patients, 14 had microscopic evidence of cancer in the specimen (2.48%) and 5 had a proven second primary malignancy in the foregut (1 in the lung, 0.18%, and 4 in the oropharynx, 0.70%). In 1 of the 14 patients, a high-grade sarcoma was diagnosed and the patient died within 1 year of diagnosis. In the treatment of our ORN patient population, a total of 19 malignancies were found collectively (3.37%). Of the 564 patients, 352 were men and 212 were women. The median age was 46 years (range, 33 to 97 years). Head and neck squamous cell carcinoma represented 531 cases in our sample, followed by 28 cases of salivary gland carcinoma and only 5 cases of sarcoma.

CONCLUSIONS

Although the finding of malignancy in ORN patients is relatively rare (3.37% in this study), oral and maxillofacial surgeons should be cognizant of its potential presence. The treatment of malignant disease is different than that of ORN, and a multidisciplinary treatment approach is recommended if a malignancy is diagnosed in an ORN patient.

Tissue repair in osteoradionecrosis using pentoxifylline and tocopherol--report of three cases

PURPOSE

Osteoradionecrosis is a complication of head and neck radiotherapy, with a difficult resolution and no well-established treatment. The disease progression can cause important loss on patient's quality of life after cancer treatment. The options for treatment are limited and include clinical monitoring, prescription, or surgical procedures. As an alternative for bone necrosis treatment, a combination of drugs, pentoxifylline and tocopherol, can be used. Studies have shown that this combination significantly reduces chronic radiotherapy damage. The article reports successful treatment with this prescription protocol.

METHODS

We report three cases of patients referred to the Service of Oral and Maxillofacial Surgery at Erasto Gaertner Hospital, in Curitiba, Brazil. They were submitted to radiotherapy for the treatment of malignant head and neck tumors and later developed osteoradionecrosis. They were treated with the combination pentoxifylline and tocopherol.

RESULTS

All patients achieved complete remission in less than 1 year, with complete healing of bone exposure and without clinical symptoms.

CONCLUSIONS

This results show that this combination of drugs is beneficial in cases of bone necrosis induced by radiation, avoiding more aggressive treatments and reducing morbidity.

An Athymic Rat Model for Mandibular Osteoradionecrosis Allowing for Direct Translation of Regenerative Treatments

Objective

We aim to create a model of mandibular osteoradionecrosis in athymic rats. Athymic rats provide an immunosuppressed environment whereby human stem cells and biomaterials can be used to investigate regenerative solutions for osteoradionecrosis, bridging the gap between in vivo testing and clinical application.

Study Design

Prospective animal study.

Setting

Academic otolaryngology department laboratory.

Subjects and Methods

After Institutional Animal Care and Use Committee approval, 10 athymic nude rats were divided into 2 groups. The experimental group (n = 6) underwent irradiation (20 Gy), while the control group (n = 4) underwent sham irradiation catheter placement only. All 10 rats underwent extraction of the second mandibular molar 7 days later. The rats were sacrificed 28 days after dental extraction, and their mandibles were harvested. The mandibles were examined with histologic analysis and bone volume analysis based on 3-dimensional micro–computed tomography.

Results

All 10 rats survived the experiment period. Radiographic and histologic analysis revealed decreased bone formation in the experimental group compared with the control group. Jaw region volume ratio was 0.83 for the experimental group versus 0.97 in the control group ( P = .003). The region-of-interest volume ratio was 0.75 in the experimental group and 0.97 in the control group ( P = .005). Histologically, there were increased osteoclasts ( P = .02) and decreased osteoblasts ( P = .001) as well as increased fibrosis in the experimental group versus the control group.

Conclusion

Mandibular osteoradionecrosis can be effectively and reproducibly produced in an athymic rat model. This will allow further research to study regenerative medicine in an athymic rat model.

How we fix free flaps to the bone in oral and oropharyngeal reconstructions

PURPOSE

The use of suture anchors has been described in orthopedic, hand, oculoplastic, temporomandibular joint and in aesthetic surgery, but no study reports the use of the Mitek® anchors (Depuy Mitek Surgical Products, Inc. Raynham, Massachusetts) for fixing the free flaps used in oncologic oral and oropharyngeal reconstruction.

MATERIALS AND METHODS

In this prospective non-randomized study, 9 patients underwent surgical resection of oral or oropharyngeal cancer followed by a free flap reconstruction; mini anchors were used to fix the flap directly to the bone. We collected data regarding the patients, the tumor stage, the surgical procedure, the radiotherapy and the number of anchors used.

RESULTS

The average follow-up was 28months (range 24-38).We observed no complications with trans-oral, sub-mandibular and trans-mandibular approach in both oral and oropharyngeal reconstructions. All anchors became osteo-integrated and no complications occurred after radiotherapy.

CONCLUSIONS

In our opinion this device favors free flap adhesion to the bone. We registered no postoperative complications related to the use of the device which looks suitable for use in irradiated tissues. The radiotherapy did not cause any long-term complications related to the use of Mitek® mini bone anchors.

Three-phase bone scintigraphy for imaging osteoradionecrosis of the jaw

This study evaluates the diagnostic utility of 3-phase bone scintigraphy for diagnosing osteoradionecrosis of the jaw (ORNJ).

METHODS

Thirty-two consecutive patients with a history of radiation to the head and neck region (range, 62-70 Gy; mean, 68 Gy; median, 69 Gy) due to squamous cell cancer and suspected ORNJ underwent 3-phase bone scans after injection of 520 to 750 MBq of Tc-MPD. In addition to planar scans, tomographic images (SPECT) were acquired in the second phase and SPECT/CT images during the third phase. Histopathologic findings (n = 18) and clinical follow-up (n = 14) served as reference standard for osteoradionecrosis.

RESULTS

The first, second, and third phases of planar images were rated positive in 18/32 patients (56.3%), 25/32 (78.1%), and 27/32 patients (84.4%), respectively. The late SPECT was positive in all patients (32/32, 100%), respectively. Histopathologic findings available in 18/32 patients (56.3%) confirmed ORNJ in all subjects. Acute inflammation was histologically proven in 18/18 specimens (100%) and additional chronic inflammation in 12/18 (66.7%). In 13/18 (72.2%) specimens, superinfection was evident histopathologically. A photopenic defect with surrounding hypermetabolism, a reported hallmark of ORJN, was found in less than 5%.

CONCLUSIONS

The predominant scintigraphic pattern of osteoradionecrosis includes increased bone mineralization phase in all patients. Central photopenia, reportedly a typical bone scan finding in bisphosphonate-induced osteonecrosis, was not characteristic for ORNJ. A differentiation of acute from chronic inflammatory processes was not possible.

Effects of the dose-volume relationship on and risk factors for maxillary osteoradionecrosis after carbon ion radiotherapy

Background

Osteoradionecrosis (ORN) is a critical complication after carbon ion (C-ion) or photon radiotherapy (RT) for head and neck tumors. However, the risk factors for ORN after C-ion RT remain unclear. Therefore, the present study aimed to investigate the effects of the dose-volume relationship on and risk factors for ORN development after C-ion RT. We, however, focused on the maxillary bone because most tumors treated with C-ion RT were primarily located in the sinonasal cavity.

Methods

The patients enrolled in this study received more than 10% of the prescribed total dose of 57.6 Gy equivalent (GyE) in 16 fractions to their maxilla. All patients were followed up for more than 2 years after C-ion RT. Those with tumor invasion to the maxilla before C-ion RT or local recurrence after the treatment were excluded from the study to accurately evaluate the effects of irradiation on the bone. Sixty-three patients were finally selected. The severity of ORN was assessed according to the Common Terminology Criteria for Adverse Events version 4.0. The correlation between clinical and dosimetric parameters and ORN incidence was retrospectively analyzed.

Results

The median follow-up period was 79 months. Of the 63 enrolled patients, 26 developed ORN of grade ≥1. Multivariate analysis revealed that the maxilla volume receiving more than 50 GyE (V50) and the presence of teeth within the planning target volume were significant risk factors for ORN. Dose-volume histogram analysis revealed that V10 to V50 parameters were significantly higher in patients with ORN than in those without ORN.

Conclusions

V50 and the presence of teeth within the planning target volume were independent risk factors for the development of ORN after C-ion RT using a 16-fraction protocol.

MRI findings of radiation-induced changes of masticatory muscles: a systematic review

BACKGROUND

Radiotherapy to the head and neck regions can result in serious consequences to the temporomandibular joint (TMJ) and chewing muscles. Magnetic resonance imaging (MRI) demonstrates soft-tissue alterations after radiotherapy, such as morphology and signal intensity.

OBJECTIVE

The purpose of this review is to critically and systematically analyse the available evidence regarding the masticatory muscles alterations, as demonstrated on MRI, after radiotherapy for head and neck cancer.

DATA SOURCES

Electronic search of MEDLINE, EMBASE, EBM reviews and Scopus.

INCLUSION CRITERIA

Reports of any study design investigating radiation-induced changes in masticatory muscles after radiotherapy in patients with head and neck cancer were included.

RESULTS AND SYNTHESIS METHODS

An electronic database search resulted in 162 papers. Sixteen papers were initially selected as potentially relevant studies; however, only four papers satisfied all inclusion criteria. The included papers focused on the MRI appearance of masticatory muscles following radiotherapy protocol. Two papers reported outcome based on retrospective clinical and imaging records, whereas the remaining two papers were case reports. Irradiated muscles frequently show diffuse increase in T2 signal and post-gadolinium enhancement post-irradiation. Also, muscle size changes were reported based on subjective comparison with the contralateral side. The quality of all included papers was considered poor with high risk of bias.

CONCLUSION

There is no evidence that MRI interpretations indicate specific radiation-induced changes in masticatory muscles. There is a clear need for a cohort study comparing patients with pre- and post-radiotherapy MRI.

Multicenter phase II trial of preoperative chemoradiotherapy with S-1 for locally advanced oral squamous cell carcinoma

Purpose

We evaluated whether preoperative chemotherapy with S-1 and concurrent radiotherapy is feasible and efficacious in the treatment of advanced oral squamous cell carcinoma.

Methods

Participants comprised 39 patients with oral carcinoma (stage III, n = 15; stage IVA, n = 24). All patients received a total radiation dose of 40 Gy, in once-daily 2-Gy fractions, and received S-1 at 65 mg/m²/day for 5 consecutive days, over 4 consecutive weeks with concurrent radiotherapy.

Results

Hematological toxicity was mild and reversible. The most common non-hematological toxicity was grade 3 mucositis, but this was transient and tolerable. Radical surgery was performed for 37 patients, with the remaining 2 patients declining the surgery. Postoperatively, local failure developed in 1 patient, and neck failure in 2 patients. Distant metastases were identified in 4 patients. At a median follow-up of 38.0 months (range 23–88 months), locoregional control, disease-specific survival, and overall survival rates at 3 years were 91.5, 83.8, and 83.8 %, respectively.

Conclusion

Concurrent administration of S-1 and radiotherapy combined with surgery offers a well-tolerated method of successfully treating advanced oral squamous cell carcinoma. The locoregional control rate remains high even at 3 years of follow-up, and no serious adverse effects have been encountered.

Osteoradionecrosis and radiation dose to the mandible in patients with oropharyngeal cancer

PURPOSE

To determine the association between radiation doses delivered to the mandible and the occurrence of osteoradionecrosis (ORN).

METHODS AND MATERIALS

We reviewed the records of 402 oropharyngeal cancer patients with stage T1 or T2 disease treated with definitive radiation between January 2000 and October 2008 for the occurrence of ORN. Demographic and treatment variables were compared between patients with ORN and those without. To examine the dosimetric relationship further, a nested case-control comparison was performed. One to 2 ORN-free patients were selected to match each ORN patient by age, sex, radiation type, treatment year, and cancer subsite. Detailed radiation treatment plans for the ORN cases and matched controls were reviewed. Mann-Whitney test and conditional logistic regression were used to compare relative volumes of the mandible exposed to doses ranging from 10 Gy-60 Gy in 10-Gy increments.

RESULTS

In 30 patients (7.5%), ORN developed during a median follow-up time of 31 months, including 6 patients with grade 4 ORN that required major surgery. The median time to develop ORN was 8 months (range, 0-71 months). Detailed radiation treatment plans were available for 25 of the 30 ORN patients and 40 matched ORN-free patients. In the matched case-control analysis, there was a statistically significant difference between the volumes of mandible in the 2 groups receiving doses between 50 Gy (V50) and 60 Gy (V60). The most notable difference was seen at V50, with a P value of .02 in the multivariate model after adjustment for the matching variables and dental status (dentate or with extraction).

CONCLUSIONS

V50 and V60 saw the most significant differences between the ORN group and the comparison group. Minimizing the percent mandibular volume exposed to 50 Gy may reduce ORN risk.

Clinical evaluation of intensity-modulated radiotherapy for head and neck cancers

Radiotherapy and surgery are the principal curative modalities in treatment of head and neck cancer. Conventional two-dimensional and three-dimensional conformal radiotherapy result in significant side effects and altered quality of life. Intensity-modulated radiotherapy (IMRT) can spare the normal tissues, while delivering a curative dose to the tumour-bearing tissues. This article reviews the current role of IMRT in head and neck cancer from the point of view of normal tissue sparing, and also reviews the current published literature by individual head and neck cancer subsites. In addition, we briefly discuss the role of image guidance in head and neck IMRT, and future directions in this area.

Organ-sparing radiation therapy for head and neck cancer

To improve locoregional tumor control and survival in patients with locally advanced head and neck cancer (HNC), therapy is intensified using altered fractionation radiation therapy or concomitant chemotherapy. However, intensification of therapy has been associated with increased acute and late toxic effects. The application of advanced radiation techniques, such as 3D conformal radiation therapy and intensity-modulated radiation therapy, is expected to improve the therapeutic index of radiation therapy for HNC by limiting the dose to critical organs and possibly increasing locoregional tumor control. To date, Review articles have covered the prevention and treatment of radiation-induced xerostomia and dysphagia, but few articles have discussed the prevention of hearing loss, brain necrosis, cranial nerve palsy and osteoradionecrosis of the mandible, which are all potential complications of radiation therapy for HNC. This Review describes the efforts to prevent therapy-related complications by presenting the state of the art evidence regarding advanced radiation therapy technology as an organ-sparing approach.

Mandibular Osteoradionecrosis in Squamous Cell Carcinoma of the Oral Cavity and Oropharynx

Objective. Mandibular osteoradionecrosis (ORN) is a serious complication of radiotherapy (RT) in head and neck cancer patients. The aim of this study was to analyze the incidence of and risk factors for mandibular ORN in squamous cell carcinoma (SCC) of the oral cavity and oropharynx.

Study Design. Case series with chart review.

Setting. University tertiary care center for head and neck oncology.

Subjects and Methods. Seventy-three patients treated for stage I to IV SCC of the oral cavity and oropharynx between 2000 and 2007, with a minimum follow-up of 2 years, were included in the study. Treatment modalities included both RT with curative intent and adjuvant RT following tumor surgery. The log-rank test and Cox model were used for univariate and multivariate analyses.

Results. The incidence of mandibular ORN was 40% at 5 years. Using univariate analysis, the following risk factors were identified: oral cavity tumors ( P < .01), bone invasion ( P < .02), any surgery prior to RT ( P < .04), and bone surgery ( P < .0001). By multivariate analysis, mandibular surgery proved to be the most important risk factor and the only one reaching statistical significance ( P < .0002).

Conclusion. Mandibular ORN is a frequent long-term complication of RT for oral cavity and oropharynx cancers. Mandibular surgery before irradiation is the only independent risk factor. These aspects must be considered when planning treatment for these tumors.

Re-assessment of chronic radio-induced tissue damage in a rat hindlimb model

Radiotherapy is successfully used to treat neoplastic lesions, but may adversely affect normal tissues within the irradiated volume. However, additional clinical and para-clinical data are required for a comprehensive understanding of the pathogenesis of this damage. We assessed a rat model using clinical records and medical imaging to gain a better understanding of irradiation-induced tissue damage. The hindlimbs of the rats in this model were irradiated with a single dose of 30 or 50 Gy. Sequential analysis was based on observation records of stage and planar scintigraphy. Additional radiography, radiohistology and histology studies were performed to detect histological alterations. All animals developed acute and late effects, with an increased severity after a dose of 50 Gy. The bone uptake of (99m)Tc-HDP was significantly decreased in a dose- and time-dependent manner. Histologically, significant tissue damage was observed. After the 50 Gy irradiation, the animals developed lesions characteristic of osteoradionecrosis (ORN). Radiographic and histological studies provided evidence of lytic bone lesions. Our rat model developed tissue damage characteristic of radiation injury after a single 30 Gy irradiation and tissue degeneration similar to that which occurs during human ORN after a 50 Gy irradiation. The development of this animal model is an essential step in exploring the pathogenesis of irradiation-induced tissue damage, and may be used to test the efficacy of new treatments.

Preoperative concurrent chemotherapy with S-1 and radiotherapy for locally advanced squamous cell carcinoma of the oral cavity: phase I trial

Background

This study was conducted to identify a recommended dose for S-1, used in combination with 40-Gy radiation.

Methods

Thirty patients, 15 each with stage III and IVA oral carcinoma, were enrolled. All patients received a total dose of 40-Gy. For the S-1 treatment, patients were given either the standard Japanese dose, calculated according to body surface area, or a reduced dose. Groups consisting of at least three patients were given S-1 according to one of 8 regimens.

Results

Hematologic toxicity was mild and reversible. The most common nonhematologic toxicity was mucositis. At level 8 that was the standard S-1 dose for 5 days per week for 4 weeks, dose-limiting toxicity was observed when 2 patients had grade 4 mucositis. This level was thus deemed the maximum tolerated dose for the regimen.

Conclusions

The recommended dose of S-1 with concurrent radiotherapy was the reduced dose of S-1 given for 5 days per week, for 4 consecutive weeks. Preoperative S-1 and concurrent radiotherapy was well tolerate and feasible and warrants a phase II study.

Advances in radiotherapy for head and neck cancer

Radiotherapy and surgery are the principal curative modalities in treatment of head and neck cancer. Conventional (two dimensional, 2D and three-dimensional conformal radiotherapy, 3DCRT) result in significant side-effects and altered quality of life. Intensity modulated radiotherapy (IMRT) can spare the normal tissues, while delivering a curative dose to the tumour bearing tissues. Technical advances like volumetric intensity modulated arc therapy (VMAT) have helped optimise IMRT further. Image guided radiotherapy (IGRT) can be used to aid target delineation and also help reduce the PTV margins to further enhance the therapeutic ratio. Particle therapy using protons provides significant advantage in terms of normal tissue sparing and is recommended for small cranial tumours and in radiotherapy for paediatric patients.