Osteoradionecrosis of the jaws--a current overview--part 1: Physiopathology and risk and predisposing factors

Fibular free flap necrosis after mandibular reconstruction surgery with osteoradionecrosis: Establishment and verification of an early warning model

OBJECTIVE

Fibular free flap necrosis (FFFN) is the most common complication in patients with osteoradionecrosis (ORN) after mandibular reconstruction surgery. However, there are no effective forecasting tools at present. This research is aimed to establish and verify a nomogram model to predict the risk of FFFN after mandibular reconstruction surgery in ORN patients.

METHODS

A total of 193 ORN patients with mandibular reconstruction using fibular free flap (150 cases in the model group and 43 cases in the validation group) were enrolled in this study. In the model group, the variables were optimized by lasso regression. Then the prediction model was established by binary logistic regression analysis, and the nomogram was drawn. The bootstrap self-sampling method was used for internal verification. Moreover, 43 cases in the validation group were used for external validation.

RESULTS

The results of lasso regression and binary logistic regression analysis showed that the radiotherapy interval (≤2 years), trismus, diabetes, without deep venous anastomoses, and American society of anesthesiologists (ASA) III were the independent risk factors for FFFN after mandibular reconstruction surgery in ORNJ patients (P<0.05). Based on the above-mentioned risk factors, the nomogram model was established. The AUC values of the model group and the validation group were 0.936 and 0.964, respectively. The curve analysis showed that when the probability thresholds of the model group and the validation group were 5.699%∼98.229% and 0.413%∼99.721%, respectively. So the patient's clinical net profit rate was the highest.

CONCLUSION

A nomogram combining the factors of radiotherapy interval (≤2 years), trismus, diabetes, without deep venous anastomoses, and ASA III provided a comparatively effective way to predict the risk of FFFN after mandibular reconstruction surgery in ORN patients, which has distinct applied clinical value.

[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.

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.

Mandibular Osteoradionecrosis: Defining the Microbial Milieu and Antimicrobial Resistance at the Time of Rescue Flap Surgery

OBJECTIVE

To report the microorganisms and their antibiotic sensitivity profile from tissue cultures and stains at the time of anterolateral thigh fascia lata (ALTFL) rescue flap for management of mandibular osteoradionecrosis (ORN).

METHODS

Retrospective chart review of patients who underwent ALTFL rescue flap for native mandibular ORN between 2011 and 2022.

RESULTS

Twenty-six cases comprising 24 patients (mean age 65.4 years, 65.4% male) with mandibular ORN from whom tissue cultures and gram stain were obtained at the time of ALTFL rescue flap. 57.7% grew bacterial species, while 34.6% grew fungal species. Multibacterial speciation was noted in 26.9% of cultures. A combination of bacterial and fungal growth was also seen in 15.4% of cases. All gram-positive cocci (GPC) were pansensitive to antibiotics except for one case of Staphylococcus aureus, which was resistant to levofloxacin. Gram-negative bacilli (GNB) species were isolated in 50.0% of cases. All fungal growth was due to Candida species. No growth was noted in 23.1% of cases. Multidrug resistance was noted in 53.8% of cases when GNB was isolated.

CONCLUSION

We report 76.9% of our cases of mandibular ORN had microbial growth from tissue cultures obtained at the time of the ALTFL rescue flap. Fungal growth was noted in a substantial number of cases and should be obtained as a specimen when pursuing culture-driven antibiotic therapy. Most GPCs were pansensitive to antibiotics, while GNBs were often the harbinger of multidrug resistant mandibular ORN.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:166-169, 2024.

A systematic review and meta-analysis of osteoradionecrosis following proton therapy in patients with head and neck cancer

INTRODUCTION

Head and neck cancer ranks as the seventh most common cancer worldwide. Proton therapy is widely used in head and neck cancer. Osteoradionecrosis(ORN) is currently a commonly investigated side effect of proton therapy. A meta-analysis is needed to investigate this topic.

MATERIAL/METHODS

Two authors searched three databases, including PubMed, Embase, and Cochrane Library; the search period was from inception to June 2023. The search keyword was set to be ((("osteoradionecrosis") OR ("osteonecrosis")) AND ("proton")).

RESULTS

We initially collected 410 articles, and after article selections, 22 articles remained in our systematic reviews. Due to the overlapping of patient populations, 17 studies were finally included in our meta-analysis. The pooled grade 3 or more ORN rate is 0.01(95 % CI = 0.01-0.03). Subgroup analysis showed that IMPT didn't reduce grade 3 or more ORN compared with 3DCPT (p = 0.15).

CONCLUSIONS

Our meta-analysis showed that severe ORN rarely occurred in proton therapy for head and neck cancer patients.

Use of Phototherapy and Er-YAG Laser in the Management of Mandible Osteoradionecrosis: A Case Report

Introduction: Osteoradionecrosis (ORN) is a secondary complication from radiotherapy, which is difficult to manage and significantly reduces the life quality of the affected patients. Case Report: A 59-year-old female patient, diagnosed with infiltration by squamous cell carcinoma in the left cervical region, underwent adjuvant cervical-facial radiotherapy with a total dose of 66.6 Gy of radiation. Eight years after the diagnosis, the patient underwent multiple extractions and, subsequently, the installation of osseointegrated implants, evolving to extensive intraoral bone exposure associated with oral cutaneous fistula. The patient was initially exposed to photobiomodulation therapy (PBMT), with a low-power laser at wavelengths of 660 nm and 808 nm, and thereafter to antimicrobial photodynamic therapy (aPDT). After an improvement in the clinical condition and resolution of the oral cutaneous fistula, a surgical procedure with the Er: YAG laser was performed to remove the remaining necrotic bone. Once the ORN condition was completely treated, the patient's oral rehabilitation was implemented by the installation of an upper mucous-supported total prosthesis and a lower implant-supported prosthesis. Conclusion: The patient is in a clinical follow-up and has no signs of bone necrosis recurrence, suggesting that low and high-power laser treatment can be an effective therapeutic alternative to resolve this condition.

Utility of pre-chemoradiotherapy Pan-Immune-Inflammation-Value for predicting the osteoradionecrosis rates in locally advanced nasopharyngeal cancers

PURPOSE

The aim of this retrospective study was to explore whether pretreatment Pan-Immune-Inflammation-Value (PIV) measurements might predict the risk of mandibular osteoradionecrosis (ORN) in patients receiving concurrent chemoradiotherapy (CCRT) for locally advanced nasopharyngeal cancer (LA-NPC).

METHODS

The platelet, monocyte, neutrophil, and lymphocyte counts acquired on the first day of CCRT were used to compute pretreatment PIV levels: PIV = (Platelets × Monocytes × Neutrophils) ÷ Lymphocytes. Receiver operating characteristic curve analysis was used to determine the association between ORN rates and PIV levels. Spearman correlation analysis was used to examine the probable intergroup correlations. The potential link between the pretreatment PIV levels and the post-treatment ORN rates was determined as the primary objective.

RESULTS

21 (10.0%) of 210 eligible patients were diagnosed with ORN. The optimal pre-CCRT PIV cutoff was 833, which separated patients into two PIV groups with divergent ORN prevalence estimates: Group 1: PIV < 833 (N = 153), and Group 2: PIV ≥ 833 (N = 57). The comparison analysis found that the PIV ≥ 833 cohort had significantly higher ORN rates than the PIV < 833 cohort (29.8% vs. 2.6%; P < 0.001). Other characteristics linked to significantly higher ORN rates were the patient's continuing smoking, the use of the Three-dimensional conformal radiation therapy technique, the mean mandibular dose of ≥ 58.1 Gy, the number of tooth extractions before CCRT ≥ 4, and the presence of tooth extractions after CCRT. The independent importance of all factors on higher ORN occurrence rates were retained in multivariate analysis (P < 0.05).

CONCLUSIONS

Our findings revealed a strong link between aggravated inflammatory response and ORN genesis, with high pretreatment PIV levels related to significantly higher ORN rates.

Valero's host index is useful in predicting radiation-induced trismus and osteoradionecrosis of the jaw risks in locally advanced nasopharyngeal carcinoma patients

BACKGROUND

In the absence of previous research, we sought to assess the H-Index's predictive significance for radiation-induced trismus (RIT) and osteoradionecrosis of the jaw (ORNJ) in patients with locally advanced nasopharyngeal carcinoma (LA-NPC) receiving concurrent chemoradiotherapy (C-CRT).

PATIENTS AND METHODS

The research comprised 295 LA-NPC patients who had C-CRT and pre- and post-C-CRT oral exams between June 2010 and December 2021. The H-Index was calculated using neutrophils, monocytes, lymphocytes, hemoglobin, and albumin measurements obtained on the first day of C-CRT. Patients were divided into three and two H-index groups, respectively, based on previously established cutoff values (1.5 and 3.5) and the cutoff value determined by our receiver operating characteristic (ROC) curve analysis. The primary objective was the presence of any significant connections between pretreatment H-Index groups and post-C-CRT RIT and ORNJ rates.

RESULTS

RIT and ORNJ was diagnosed in 46 (15.6%) and 13 (7.8%) patients, respectively. The original H-Index grouping could only categorize RIT and ORNJ risks at a cutoff value of 3.5, with no significant differences in RIT and ORNJ rates between groups with H-Index 1.5 and 1.5 to 3.5 (P < 0.05 for each). The ideal H-Index cutoff for both RIT and ORNJ rates was found to be 5.5 in ROC curve analysis, which divided the entire research population into two groups: H-Index ≤ 5.5 (N = 195) and H-Index > 5.5 (N = 110). Intergroup comparisons revealed that patients in the H-Index > 5.5 group had significantly higher rates of either RIT (31.8% vs. 5.9%; P < 0.001) or ORNJ (17.3% vs. 2.2%; P < 0.001) than their H-Index ≤ 5.5 counterparts. The results of the multivariate analysis showed that H-Index > 5.5 was independently linked to significantly higher RIT (P < 0.001) and ORNJ (P < 0.001) rates.

CONCLUSION

Pre-C-CRT H-Index > 5.5 is associated with significantly increased RIT and ORNJ rates in LA-NPC patients receiving definitive C-CRT.

Clinical outcomes of dental implants in head and neck cancer patients: An overview

OBJECTIVE

The aim of this study was to evaluate the clinical outcomes of dental implants (DIs) in patients with head and neck cancer (HNC) treated with radiotherapy (RT), isolated chemotherapy, or bone modifying agents (BMAs).

STUDY DESIGN

This study was registered in the Prospective Register of Systematic Reviews (CRD42018102772); conducted via the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist; and based on PubMed, Scopus, Embase, Cochrane Library, Web of Science, and gray literature searches. The selection of studies was performed in 2 phases by 2 independent reviewers. The risk of bias (RoB) was assessed by the Measurement Tool to Assess the Methodological Quality of Systematic Reviews 2.

RESULTS

Twenty systematic reviews were included in the qualitative analysis. The majority scored as having high RoB (n = 11). Primary DIs placement in the mandible of patients with HNC subjected to RT doses <50 Gy was associated with better survival rates.

CONCLUSIONS

The placements of DIs could be considered safe in patients with HNC in sites of alveolar bone that received RT (≤5000 Gy); however, no conclusions could be made in patients with cancer managed by chemotherapy or BMAs. Due to the heterogeneity of studies included, the recommendation for DIs placement in patients with cancer should be carefully considered. Future better controlled randomized clinical trials are required to provide enhanced clinical guidelines for best patient care.

Can the prophylactic use of pentoxifylline and tocopherol before dental extractions prevent osteoradionecrosis? A systematic review

PURPOSE

This systematic review aimed to determine whether the pentoxifylline and tocopherol (PENTO) protocol effectively reduce the risk of osteoradionecrosis (ORN) in patients undergoing tooth extraction after head and neck radiotherapy.

METHODS

We searched PubMed, SCOPUS, LILACS, EMBASE, Web of Science, and Cochrane databases up to August 2022. We considered only studies that included patients diagnosed with head and neck cancer undergoing tooth extraction with PENTO prophylaxis after radiotherapy.

RESULTS

Of the 642 studies identified, 4 were included. Across the included studies, 387 patients had 1871 teeth extracted while on PENTO prophylaxis. The interval of the PENTO protocol differed among the studies included. Overall, a total of 12 (3.1%) patients had ORN, whereas at the individual tooth level analysis the ORN rate was 0.9%.

CONCLUSIONS

Insufficient evidence exists to promote using the PENTO protocol before dental extractions to prevent ORN.

Evaluation of Anterolateral Thigh Fascia Lata Rescue Flap for Mandibular Osteoradionecrosis

Importance

Mandibular osteoradionecrosis (ORN) is a progressive disease that can be difficult to treat. Conservative measures often fail, while conventional definitive management requires a morbid segmental resection with osteocutaneous reconstruction. Evidence of the anterolateral thigh fascia lata (ALTFL) rescue flap technique's safety, effectiveness, and long-term outcomes is needed.

Objective

To determine the long-term outcomes of the ALTFL rescue flap procedure for treating patients with mandibular ORN.

Design, Settings, and Participants

This was a retrospective medical record review performed at a single tertiary-level academic health care institution with patients who were appropriate candidates for the ALTFL procedure to treat mandibular ORN from March 3, 2011, to December 31, 2022. Data analyses were performed from January 1 to March 26, 2023.

Main Outcomes and Measures

Patient characteristics, preoperative radiographic Notani staging, intraoperative defect size, length of stay, complication rates, and clinical and radiographic findings of progression-free intervals.

Results

The study population of 43 patients (mean [SD] age, 66.1 [47-80] years; 24 [55.8%] male individuals) included 52 cases of mandibular ORN. The preoperative Notani staging of the study population was known for 46 of the 52 total cases: 11 cases (23.9%) were stage I; 21 (45.7%), stage II; and 14 (30.4%), stage III. The mean defect area was 20.9 cm2. Successful arrest of ORN disease progression was noted in the clinical and radiographic findings of 50 of the 52 (96.2%) cases, with only 2 (3.8%) cases subsequently requiring fibular free flap reconstruction. The major complication rate was 1.9% (1 case). Clinical and radiographic progression-free intervals were assessed, and no statistically significant differences were noted between Notani staging groups (log-rank P = .43 and P = .43, respectively); ie, patients with stage III disease had no significant difference in risk of clinical (HR, 0.866; 95% CI, 0.054-13.853) or radiographic (HR, 0.959; 95% CI, 0.059-15.474) progression vs those with stage I disease. Weibull profiling revealed 96.9%, 94.6%, and 93.1% successful mandibular ORN arrest at 1, 3, and 5 years, respectively. The major complication rate was 1.9%. Mean (SD) length of stay was 2.7 (0.0-7.0) days. Mean (SD) radiographic follow-up was 29.3 (30.7) months.

Conclusions and Relevance

The findings of this large retrospective patient case series support the continued success of the ALTFL rescue flap technique, a safe and highly effective long-term treatment for mandibular ORN in carefully selected patients.

The predictive value of pretreatment hemoglobin-to-platelet ratio on osteoradionecrosis incidence rates of locally advanced nasopharyngeal cancer patients managed with concurrent chemoradiotherapy

BACKGROUND

This retrospective study aimed to investigate whether the pretreatment hemoglobin-to-platelet ratio (HPR) could predict the risk of osteoradionecrosis (ORN) in patients receiving concurrent chemoradiotherapy (C-CRT) for locally advanced nasopharyngeal carcinoma (LA-NPC).

METHODS

ORN cases were reported from the records of LA-NPC patients who had oral examinations before and after C-CRT. The pretreatment HPR values were calculated on the first day of C-CRT. The connection between HPR values and ORN occurrences was determined using receiver operating characteristic curve analysis. The primary endpoint was the relationship between the pretreatment HPR values and post-C-CRT ORN incidence rates, while secondary endpoints included the identification of other putative ORN risk factors.

RESULTS

We distinguished 10.9% incidences of ORN during the post-C-CRT follow-up period among 193 LA-NPC patients. The optimal cutoff for pre-C-CRT HPR was 0.48 that grouped the patients into two HPR groups with fundamentally different post-C-CRT ORN incidence rates: Group 1: HPR ≤ 0.48 (N = 60), and Group 2: HPR > 0.48 (N = 133). The comparative analysis indicated a significantly higher ORN incidence in HPR ≤ 0.48 group (30%; P < 0.001). The other factors associated with meaningfully increased ORN rates included the presence of pre-C-CRT ≥ 5 teeth extractions, mandibular volume receiving ≥ 64 Gy, post-C-CRT tooth extractions, mean mandibular dose ≥ 50.6 Gy, and C-CRT to tooth extraction interval > 5.5 months.

CONCLUSION

Low pretreatment HPR levels were independently and unequivocally linked to significantly increased incidence of ORN post-C-CRT. Pre-C-CRT HPR levels may be used to estimate the incidence of ORN and be useful for taking preventive and therapeutic measures in these patients such as monitoring oral hygiene with strict follow-up, avoidance of unnecessary tooth extractions, particularly after C-CRT, and use of more rigorous mandibular RT dose limits.

Applications of Hydrogels in Drug Delivery for Oral and Maxillofacial Diseases

Oral and maxillofacial diseases have an important impact on local function, facial appearance, and general health. As a multifunctional platform, hydrogels are widely used in the biomedical field due to their excellent physicochemical properties. In recent years, a large number of studies have been conducted to adapt hydrogels to the complex oral and maxillofacial environment by modulating their pore size, swelling, degradability, stimulus-response properties, etc. Meanwhile, many studies have attempted to use hydrogels as drug delivery carriers to load drugs, cytokines, and stem cells for antibacterial, anticancer, and tissue regeneration applications in oral and maxillofacial regions. This paper reviews the application and research progress of hydrogel-based drug delivery systems in the treatment of oral and maxillofacial diseases such as caries, endodontic diseases, periodontal diseases, maxillofacial bone diseases, mucosal diseases, oral cancer, etc. The characteristics and applications of hydrogels and drug-delivery systems employed for the treatment of different diseases are discussed in order to provide a reference for further research on hydrogel drug-delivery systems in the future.

Pre-chemoradiotherapy low hemoglobin levels indicate increased osteoradionecrosis risk in locally advanced nasopharyngeal cancer patients

PURPOSE

We aimed to determine whether pretreatment hemoglobin (Hb) levels can predict the risk of osteoradionecrosis (ORN) in patients receiving concurrent chemoradiotherapy (CCRT) for locally advanced nasopharyngeal carcinoma (LA-NPC).

METHODS

ORN cases were identified from the records of LA-NPCs who had oral exams before and after CCRT. All Hb measurements were obtained on the first day of treatment. Receiving operating characteristic curve analysis was used to determine the relationship between Hb levels and ORN rates. The relationship between pretreatment Hb levels and ORN rates served as the primary endpoint, and secondary endpoints included the discovery of additional potential ORN risk factors.

RESULTS

Among the 263 eligible LA-NPCs, we identified 8.7% ORN cases. The ideal cutoff Hb before CCRT was 10.6 g/dL. It was revealed that HPR ≤ 10.6 group had a significantly higher ORN rate (32.5% vs. 1.5% for Hb > 10.6; P < 0.001). The mandibular V59.8 ≥ 36% Gy, pre-CCRT ≥ 4 tooth extractions, the presence of post-CCRT tooth extractions, and the time of post-CCRT tooth extractions > 8 months were the other factors associated with significantly increased ORN rates (P < 0.05 for each).

CONCLUSION

Low pre-CCRT Hb levels appeared to be independently linked to significantly higher ORN rates. Pretreatment Hb levels may be used to establish preventive measures and predict ORN.

Osteoradionecrosis versus Cancer Recurrence: An Unresolved Clinical Dilemma

INTRODUCTION

Osteoradionecrosis is a rare and debilitating risk of definitive chemoradiotherapy for head and neck squamous cell carcinoma. It is difficult to distinguish between osteoradionecrosis and recurrent or progressive disease, as clinical and radiologic features may be similar. Our aim was to compare the clinical presentation and radiologic features of osteonecrosis with those of recurrent or progressive cancer.

METHODS

We conducted a single-center case series of 19 patients with head and neck squamous cell carcinoma diagnosed between 2011 and 2019 who subsequently developed clinical and/or radiological suspicion of osteoradionecrosis. The population was a referred sample from head and neck cancer physicians at Northwell Health Cancer Institute. Clinician notes and imaging reports were reviewed to assign a final diagnosis of either cancer, osteonecrosis, or indeterminate.

RESULTS

No differences were found in the clinical presentation or radiologic features between groups. Median time between treatment and development of symptoms was longer in patients with a final diagnosis of osteoradionecrosis than recurrent or progressive disease (5 vs. 3 months), but this difference was not statistically significant. Radiation dose and type were not associated with diagnosis. Mean standard uptake value maximums on positron emission tomography/computed tomography were significantly higher in the cancer group (median 14.8 vs. 9.1, p < 0.0152). At 1 year after first suspicion of osteoradionecrosis, 100% of osteoradionecrosis patients were alive, versus 28.6% of cancer patients.

DISCUSSION/CONCLUSION

There is significant overlap in clinical and radiologic features of osteoradionecrosis and cancer. Standard uptake maximums may be helpful in predicting diagnosis. Occurrence of symptoms within 6 months of completing chemoradiotherapy should raise the concern for malignancy.

Advances and Controversies in the Management of Osteoradionecrosis After Head and Neck Cancer Treatment: A Narrative Review

Osteoradionecrosis (ORN) is a painful and debilitating serious late complication following treatment for head and neck cancer (HNC) often requiring surgical resection of the jaw and complex multidisciplinary management. An important aggravating factor for mandibular ORN is surgical trauma, commonly dental extractions or implant placement following head and neck radiotherapy. The evidence on the treatment protocols ranges from conservative management to more radical surgical strategies including the use of hyperbaric oxygen therapy. The available evidence on the preventive approaches for ORN includes prophylactic dental care prior to radiotherapy, the use of hyperbaric oxygen (HBO) treatment and prophylactic antibiotics for post-radiotherapy extractions. However, the efficacy of hyperbaric oxygen therapy has been questioned recently signifying poor understanding of the pathophysiology of the condition and therapies targeting the fibroatrophic process have become a focus of ORN treatment. Implementing recent IMRT radiation techniques has also shown evidence to reduce the incidence of ORN. This review provides an insight into the variations in definition and classification of the ORN, the controversies in its pathophysiology and the advances in the prevention and management.

Photobiomodulation therapy in management of cancer therapy-induced side effects: WALT position paper 2022

Disclaimer

This article is based on recommendations from the 12th WALT Congress, Nice, October 3-6, 2018, and a follow-up review of the existing data and the clinical observations of an international multidisciplinary panel of clinicians and researchers with expertise in the area of supportive care in cancer and/or PBM clinical application and dosimetry. This article is informational in nature. As with all clinical materials, this paper should be used with a clear understanding that continued research and practice could result in new insights and recommendations. The review reflects the collective opinion and, as such, does not necessarily represent the opinion of any individual author. In no event shall the authors be liable for any decision made or action taken in reliance on the proposed protocols.

Objective

This position paper reviews the potential prophylactic and therapeutic effects of photobiomodulation (PBM) on side effects of cancer therapy, including chemotherapy (CT), radiation therapy (RT), and hematopoietic stem cell transplantation (HSCT).

Background

There is a considerable body of evidence supporting the efficacy of PBM for preventing oral mucositis (OM) in patients undergoing RT for head and neck cancer (HNC), CT, or HSCT. This could enhance patients’ quality of life, adherence to the prescribed cancer therapy, and treatment outcomes while reducing the cost of cancer care.

Methods

A literature review on PBM effectiveness and dosimetry considerations for managing certain complications of cancer therapy were conducted. A systematic review was conducted when numerous randomized controlled trials were available. Results were presented and discussed at an international consensus meeting at the World Association of photobiomoduLation Therapy (WALT) meeting in 2018 that included world expert oncologists, radiation oncologists, oral oncologists, and oral medicine professionals, physicists, engineers, and oncology researchers. The potential mechanism of action of PBM and evidence of PBM efficacy through reported outcomes for individual indications were assessed.

Results

There is a large body of evidence demonstrating the efficacy of PBM for preventing OM in certain cancer patient populations, as recently outlined by the Multinational Association for Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). Building on these, the WALT group outlines evidence and prescribed PBM treatment parameters for prophylactic and therapeutic use in supportive care for radiodermatitis, dysphagia, xerostomia, dysgeusia, trismus, mucosal and bone necrosis, lymphedema, hand-foot syndrome, alopecia, oral and dermatologic chronic graft-versus-host disease, voice/speech alterations, peripheral neuropathy, and late fibrosis amongst cancer survivors.

Conclusions

There is robust evidence for using PBM to prevent and treat a broad range of complications in cancer care. Specific clinical practice guidelines or evidence-based expert consensus recommendations are provided. These recommendations are aimed at improving the clinical utilization of PBM therapy in supportive cancer care and promoting research in this field. It is anticipated these guidelines will be revised periodically.

Utilization of a Chimeric Medial Femoral Condyle Free Flap for Mandibular Osteoradionecrosis

BACKGROUND

Primary options for oromandibular reconstruction with osteocutaneous free flaps are the vascularized fibula and iliac crest. Complications of mandible reconstruction are not uncommon and include osteomyelitis, malunion, and osteoradionecrosis (ORN) after radiation therapy. The medial femoral condyle (MFC) free flap is an established salvage option for carpal reconstruction in hand surgery, frequently used for scaphoid nonunion and avascular necrosis. We hypothesize that the MFC flap can be utilized to restore blood supply and reverse the negative effects of radiotherapy in patients who require mandibular reconstruction due to ORN.

METHODS

A retrospective chart review was conducted at Beaumont Health System, Royal Oak, for patients who underwent MFC free flap reconstruction for mandibular ORN between the years 2012 and 2018. Demographic data, operative details, complications, medical comorbidities, and patient outcomes were retrospectively gathered.

RESULTS

A total of four patients were isolated. Four patients developed ORN after resection of squamous cell carcinoma and adjuvant radiotherapy. No patients experienced donor site deficits. Revisions after MFC reconstruction were dependent on individual aesthetics and involvement of neighboring tissue. All four patients continue to be followed with no current issues to the osseous component of the MFC flap.

CONCLUSION

Utilization of the MFC periosteal flap is a viable option in selected patients to salvage nonunion/resorption of mandible reconstruction and ORN of the mandible. Our experience found that the MFC is able to provide pain resolution and healing of intraoral soft tissue defects, and may halt the progression of ORN of the mandible.

Osteoradionecrosis of the jaw: A mini review

Osteoradionecrosis (ORN) of the jaw is one of the most dreaded complications of head and neck radiation therapy. Despite the evolution of radiation treatment modalities, ORN continues to remain a therapeutic challenge and its etiopathogenesis still remains unclear. It is clinically characterized by exposed necrotic bone within the head and neck radiation field. Over the past years, several studies have reported on the definition, staging, incidence, etiology, and management of this oral complication. In this review, we summarize the literature on ORN and discuss our institutional experience and management strategies that aim to predict and mitigate risk for ORN.

The Potential Therapeutic Role of Mesenchymal Stem Cells-Derived Exosomes in Osteoradionecrosis

As one of the most serious complications of radiotherapy, osteoradionecrosis (ORN) seriously affects the quality of life of patients and even leads to death. Vascular injury and immune disorders are the main causes of bone lesions. The traditional conservative treatment of ORN has a low cure rate and high recurrent. Exosomes are a type of extracellular bilayer lipid vesicles secreted by almost all cell types. It contains cytokines, proteins, mRNA, miRNA, and other bioactive cargos, which contribute to several distinct processes. The favorable biological functions of mesenchymal stem cells-derived exosomes (MSC exosomes) include angiogenesis, immunomodulation, bone regeneration, and ferroptosis regulation. Exploring the characteristic of ORN and MSC exosomes can promote bone regeneration therapies. In this review, we summarized the current knowledge of ORN and MSC exosomes and highlighted the potential application of MSC exosomes in ORN treatment.

Bacterial Colonization of the Condyle in Patients with Advanced Mandibular Osteoradionecrosis: Analysis of Hemimandibulectomy Specimens

Advanced mandibular osteoradionecrosis (ORN) sometimes requires extended resection (e.g., hemimandibulectomy). Bacterial infection contributes to ORN pathogenesis. To control infection and determine the extent of debridement required, an understanding of bacterial spread within sites of mandibular ORN is important. The current study used a histopathological approach to assess bacterial colonization in the mandibular condyle and elucidate possible paths of bacterial spread towards the mandibular condyle. Four hemimandibulectomy specimens were selected. Areas of bone destruction were macroscopically assessed and confirmed using hematoxylin and eosin staining. Bacterial presence within mandibular condyle was confirmed with Gram staining. Bone exposure was observed in the molar area in all specimens. Macroscopic bone destruction was apparent especially near the medial side of the cortical wall. Gram staining revealed bacterial colonization of the mandibular condyle in three of the four specimens. In conclusion, bacteria tended to spread posteriorly and through the medial side of the mandibular cortical wall. In patients with advanced ORN, the potential for bacterial colonization of the mandibular condyle should be considered during treatment.

Imaging Features of Postradiotherapy Changes in Head and Neck Cancers

Radiation therapy is the mainstay in the treatment of head and neck cancers, in addition to surgery and chemotherapy. Expected radiotherapy changes evolving over time may be confused with recurrent tumor. Conversely, even residual or recurrent tumor in the setting of postradiotherapy changes may be difficult to identify clinically or even by radiological imaging. Therefore, it is important to be familiar with the temporal evolution of these changes. The purpose of this pictorial essay is thus to illustrate distinctly the expected radiotherapy changes and radiotherapy-related complications in the head and neck region and to differentiate them from tumor recurrence on routine cross-sectional imaging techniques (computed tomography and magnetic resonance imaging).

The Balance between Orthodontic Force and Radiation in the Jawbone: Microstructural, Histological, and Molecular Study in a Rat Model

Simple Summary

Patients with head and neck cancer are frequently treated by radiation, which results in a lifelong risk of damage (necrosis) to the jawbones. Some of the irradiated young patients at a later time in life may be interested in orthodontic treatment for esthetic or functional purposes. We undertook this study in order to investigate changes that occur in irradiated jawbones when mild orthodontic force is applied in a rat laboratory model. We found that one low dose of radiation had negatively affected the jawbones and that these changes were visible in X-ray images as well as in microscopic slides. The irradiated bones seemed to be denser in the X-rays and had fewer cells that usually regulate normal bone turnover, compared to non-irradiated bones. However, when orthodontic force was applied after radiation, the changes in the irradiated bones were largely, but not completely, reversed in both X-rays and microscopy to the point that bone properties were approaching those of non-irradiated, orthodontically treated, bones. The findings of this study indicate that orthodontic force may have a beneficial effect on the maintenance of jawbone vitality after radiation, but additional studies using different time-lags between radiation and orthodontic force and higher radiation doses are warranted to support these findings.

Abstract

Irradiation of facial bones is associated with a lifelong risk of osteonecrosis. In a rat model, maxillae were exposed to a single 5 Gy dose of external beam radiation and orthodontic force was applied for 2 weeks on the first maxillary molar; control rats were treated identically without radiation. Tooth movement in irradiated jaws was 30% less than in controls, representing radiation-related damage. Micro-CT, histological, and molecular outcomes of orthodontic tooth movement were studied. Microstructurally, bone parameters (trabecular thickness, bone volume fraction, bone mineral density) were significantly affected by orthodontic force but not by radiation. Histological parameters were influenced only by orthodontic force, especially by an increase in osteoclasts. A molecular study revealed a differential distribution of cells expressing pre-osteoclast markers (RANK+—majority, CD11b+, CD14+—minority), with changes being influenced by orthodontic force (increased CD11b+ and CD14+ cells) and also by radiation (decreased RANK+ cells). The activation status of osteoclasts (TRAP staining) showed an orthodontic-force-related increase, which probably could not fully compensate for the radiation-associated impairment. The overall balance showed that orthodontic force had elicited a substantial microstructural, histological, and functional normalization process in irradiated maxillae but a radiation-induced impact was still conspicuous. Additional studies are needed to validate these findings.

[State of art of photobiomodulation in the management of radiotherapy adverse events: Indications and level of evidence]

PURPOSE

To evaluate the current and potential indications of photobiomodulation (PBM) and their level of evidence in the prevention or management of radiation therapy-related side effects.

MATERIALS AND METHODS

The Embase, Medline/PubMed, Cochrane, EBSCO, Scopus, and LILACS databases were systematically reviewed to include and analyze publications of clinical studies that have assessed PBM in the prevention or management of radiotherapy-related side effects. The keywords used were "photobiomodulation"; "low level laser therapy"; "acute oral mucositis"; "acute dysphagia"; "acute radiation dermatitis"; "lymphedema"; "xerostomia"; "hyposalivation"; "trismus"; "bone necrosis"; "osteoradionecrosis"; and "radiation induced fibrosis". Prospective studies were included, whereas retrospective cohorts and non-original articles were excluded from the analysis.

RESULTS

PBM in the red or infrared spectrum has demonstrated efficacy in randomized controlled trials in the prevention and management of radiotherapy-related side effects, especially acute oral mucositis, acute radiation dermatitis, and upper extremity lymphedema. The level of evidence associated with PBM was heterogeneous, but overall was still moderate. The main shortcomings were the diversity and lack of detail in treatment protocols, which could have compromised efficiency and reproducibility of PBM results.

CONCLUSION

The published data suggest that PBM may be considered as a full-fledged supportive care for patients treated with radiotherapy, or at least in the setting of a therapeutic clinical trial. However, until strong evidence has been published on its long-term safety, the use of PBM should be considered with caution, specifically when applied near areas with proven or potential tumors. The patient should be informed of the theoretical benefits and risks of PBM in order to obtain his informed consent before treatment.

Clinical features and dosimetric evaluation of carbon ion radiation-induced osteoradionecrosis of mandible in head and neck tumors

BACKGROUND AND PURPOSE

Osteoradionecrosis (ORN) affects the patient's quality of life by making eating and maintaining oral hygiene painful. This study aimed to analyze carbon ion radiotherapy (C-ion RT)-induced ORN of the mandible.

MATERIALS AND METHODS

A retrospective study of 199 patients with head and neck tumors treated with C-ion RT was performed from 2010 to 2019. Only 11 patients with tumors located in the oropharynx and floor of the mouth were analyzed. C-ion RT consisted of 57.6 Gy or 64.0 Gy (relative biological effectiveness) in 16 fractions. The mandible was analyzed for magnetic resonance imaging (MRI) changes and bone exposure. The relationship between the radiation dose and ORN of the mandible was analyzed.

RESULTS

Five patients (45.5%) had ORN of the mandible. The median follow-up time was 68 months. The median onset times based on MRI changes and bone exposure were 9 and 15 months, respectively. Doses of 30 Gy (relative biological effectiveness) to the mandible and teeth showed the most significant effect, causing ORN at 29.5 ± 6.7 cc and 3.9 ± 1.8 cc, respectively, with cut-off values at 16.5 cc (p = 0.002) and 1.8 cc (p = 0.0059), respectively.

CONCLUSION

This is the first study reporting the incidence, onset time, and risk-predictive dosimetry parameters of C-ion RT-induced ORN of the mandible. Our study will be useful for establishing clinical strategies for C-ion RT to the head and neck near the mandible.

Practical Approach to Radiopaque Jaw Lesions

Radiopaque lesions of the jaw are myriad in type and occasionally protean in appearance. In turn, the radiologic analysis of these lesions requires a systematic approach and a broad consideration of clinical and imaging characteristics to enable reliable radiologic diagnosis. Initially categorizing lesions by attenuation pattern provides a practical framework for organizing radiopaque jaw lesions that also reflects important tissue characteristics. Specifically, the appearance of radiopaque lesions can be described as (a) densely sclerotic, (b) ground glass, or (c) mixed lytic-sclerotic, with each category representing a distinct although occasionally overlapping differential diagnosis. After characterizing attenuation pattern, the appreciation of other radiologic features, such as margin characteristics or relationship to teeth, as well as clinical features including demographics and symptoms, can aid in further narrowing the differential diagnosis and lend confidence to clinical decision making. The authors review the potential causes of a radiopaque jaw lesion, including pertinent clinical and radiologic features, and outline a simplified approach to its radiologic diagnosis, with a focus on cross-sectional CT. An invited commentary by Buch is available online. ^©RSNA, 2021.

[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.

Is Adjunctive Hyperbaric Oxygen Treatment Alone or with Surgery the Proper Management for Active and Persistent Osteoradionecrosis?

ABSTRACT

This study enrolled patients with stage 3 osteoradionecrosis. There were three treatment modalities: antibiotics, hyperbaric oxygen therapy (HBOT), and surgery. Complete healing was the primary outcome. Multiple logistic regression analysis demonstrated that surgery with HBOT improved wound healing better than HBOT alone.

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.

Does the administration of meloxicam before head and neck radiotherapy reduce the risk of mandibular osteoradionecrosis? An animal model study

OBJECTIVE

To assess whether the administration of meloxicam before head and neck radiotherapy reduces the risk of mandibular osteoradionecrosis in rats.

MATERIAL AND METHODS

Sixty male Wistar rats were randomly divided into 6 groups (n = 10) according to the meloxicam administration and radiation therapy: control (C), irradiated (I), single dose of meloxicam (M1), single dose of meloxicam and irradiated (M1I), triple dose of meloxicam (M3), triple dose of meloxicam and irradiated (M3I). Meloxicam was administrated (20 mg/kg per dose) 1 h before the radiation therapy (single dose of 20 Gy) and 24 h and 48 h after the radiation therapy for groups with two additional doses. Ten days after the radiation therapy, the three right mandibular molars were extracted from all rats, who were euthanatized after 21 or 35 days (n = 5 per group). The mandibles were assessed by macroscopic evaluation and micro-CT analysis.

RESULTS

The right hemimandibles of the irradiated groups revealed macroscopic signs of osteoradionecrosis, and those of the non-irradiated groups revealed complete gingival healing. A significant delay in alveolar socket healing in all irradiated groups was observed in the micro-CT assessment regardless meloxicam treatment.

CONCLUSION

The administration of meloxicam before head and neck radiotherapy does not reduce the risk of mandibular osteoradionecrosis when associated to dental extractions.

CLINICAL RELEVANCE

Since meloxicam has been shown to be a potential radiation-protective agent, and osteoradionecrosis physiopathology is believed to be related to an inflammatory process, possible interactions are relevant to be investigated.

Assessment of jaw osteonecrosis diagnostic criteria in cancer patients with a history of radiation therapy and exposure to bone-modifying agents

BACKGROUND

Osteoradionecrosis (ORN) of the jaw is currently defined by the development of osteonecrosis in head/neck irradiated patients, regardless of lesion exposure. To diagnose medication-related osteonecrosis of the jaw (MRONJ), a history of any radiation therapy to the jaw region must be ruled out. The aim of this study was to assess the accuracy of current osteonecrosis criteria, while introducing new modifications for improved diagnosis and treatment.

METHODS

One hundred and forty-one necrotic lesions were analyzed from patients exposed to bone-modifying agents (BMAs) and/or received head and neck regional radiation therapy, where the maximal dose of radiation exposure to the jaw osteonecrosis site was calculated. Modified diagnostic criteria were used to reassess all cases and a comparison of outcomes was performed using Pearson's Chi-Square/Fisher's exact test.

RESULTS

Only in patients with primary head and neck carcinomas did the maximal mean radiation dose in the necrotic jaw site reach ranges associated with ORN formation (>40 Gy), with individual cases showing exposures as low as 0-2 Gy. Based on the modified diagnostic criteria almost 2/3 of the necrotic cases diagnosed as ORN should be diagnosed as MRONJ.

CONCLUSIONS

ORN diagnosis should only be considered in cases of radiation exposure >40 Gy to prevent misdiagnosis and suboptimal treatment. A modified criterion for MRONJ diagnosis is recommended where radiation exposure <40 Gy in the necrotic site is included. In cases with exposure >40 Gy and BMA administration, an additional modification to diagnostic criteria of 'medication- and radiation-related osteonecrosis of the jaw', should be used.

Medication-related osteonecrosis and osteoradionecrosis of the jaws: Update and current management

Medication related osteonecrosis of the jaws (MRONJ) and osteoradionecrosis of the jaws (ORNJ) are two different diseases of quite similar appearance. MRONJ is mainly due to antiresorptive or antiangiogenic drug therapy and ORNJ to radiotherapy. The present work aimed at presenting and comparing the current knowledge on MRONJ and ORNJ. They both present as an exposure of necrotic bone and differ in some clinical or radiological characteristics, clinical course and mostly in treatment. They share similar risk factors. A tooth extraction is more frequently found as a triggering factor in MRONJ. The frequency of a maxillary localisation seems higher for MRONJ. On computed tomographic images, a periosteal reaction seems characteristic of MRONJ. More frequent pathological fractures seem to occur in ORNJ. It is mandatory, for ORNJ diagnosis, to exclude a residual or recurrent tumour using histological examination. Both MRONJ and ORNJ are challenging to treat and cannot be managed similarly. For both, it would still be worth to optimise awareness within the medical community, patients' oral hygiene and dental cares to improve their prevention and make their incidences decrease. Conservative therapy is more frequently achieved for MRONJ than ORNJ and surgical resection is more often performed for ORNJ. For both diseases, the last treatment possible in refractory cases is a surgical extensive resection with free flap reconstruction. A MRONJ classification is widely used today, whereas no consensus exists to date for ORNJ classification. We propose a classification that could play this role.

Low-Intensity Pulsed Ultrasound Modulates RhoA/ROCK Signaling of Rat Mandibular Bone Marrow Mesenchymal Stem Cells to Rescue Their Damaged Cytoskeletal Organization and Cell Biological Function Induced by Radiation

Osteoradionecrosis of the jaw (ORNJ) is an infrequent yet potentially devastating complication of head and neck radiation therapy. Low-intensity pulsed ultrasound (LIPUS) has been widely accepted as a promising method for the successful management of ORNJ, but the mechanism remains unclear. In this study, the effects of LIPUS on cytoskeletal reorganization, cell viability, and osteogenic differentiation capacity of rat mandible-derived bone marrow mesenchymal stem cells (M-BMMSCs) induced by radiation were determined by immunofluorescence staining, CCK-8 cell proliferation assay, quantification of alkaline phosphatase (ALP) activity, alizarin red staining, and real-time RT-PCR, respectively. Moreover, the involvement of the RhoA/ROCK signaling pathway underlying this process was investigated via western blot analysis. We found that radiation induced significant damage to the cytoskeleton, cell viability, and osteogenic differentiation capacity of M-BMMSCs and downregulated their expression of RhoA, ROCK, and vinculin while increasing FAK expression. LIPUS treatment effectively rescued the disordered cytoskeleton and redistributed vinculin. Furthermore, the cell viability and osteogenic differentiation capacity were also significantly recovered. More importantly, it could reverse the aberrant expression of the key molecules induced by radiation. Inhibition of RhoA/ROCK signaling remarkably aggravated the inhibitory effect of radiation and attenuated the therapeutic effect of LIPUS. In the light of these findings, the RhoA/ROCK signaling pathway might be a promising target for modifying the therapeutic effect of LIPUS on osteoradionecrosis.

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.

Bone microarchitecture and turnover in the irradiated human mandible

OBJECTIVES

The aim of this study was to assess the microarchitecture and turnover in irradiated cancellous mandibular bone and the relation with radiation dose, to elucidate the effects of radiotherapy on the mandible.

PATIENTS AND METHODS

Mandibular cancellous bone biopsies were taken from irradiated patients and controls. Micro-CT scanning was performed to analyze microstructural bone parameters. Bone turnover was assessed by histomorphometry. Local radiation dose at the biopsy site (Dmax) was estimated from radiotherapy plans.

RESULTS

Twenty-seven irradiated patients and 35 controls were included. Osteoid volume (Osteoid Volume/Bone Volume, OV/BV) [0.066/0.168 (median/interquartile range (IQR), OV/BV; %), P < 0.001], osteoid surface (Osteoid Surface/Bone Surface, OS/BS) [0.772/2.17 (median/IQR, OS/BS; %), P < 0.001] and osteoclasts number (Osteoclasts per millimetre bone surface, Ocl/mmBS; mm²) [0.026/0.123 (median/IQR, Ocl/mmBS; mm²), P < 0.001] were decreased; trabecular number (Tb.N) was lower [1.63/0.63 (median/IQR, Tb.N; 1/mm^-1), P = 0.012] and trabecular separation (Tb.Sp) [0.626/0.24 (median/IQR, Tb.Sp; μm), P = 0.038] was higher in irradiated mandibular bone. With higher Dmax, trabecular number increases (Spearman's correlation R = 0.470, P = 0.018) and trabecular separation decreases (Spearman's correlation R = -0.526, P = 0.007). Bone mineral density (BMD, milligrams hydroxyappetite per cubic centimetre, mgHA/cm³) [1016/99 (median/IQR, BMD; mgHA/cm³), P = 0.03] and trabecular separation [0.739/0.21 (median/IQR, Tb.Sp; μm), P = 0.005] are higher whereas connectivity density (Conn Dens) [3.94/6.71 (median/IQR, Conn Dens), P = 0.047] and trabecular number [1.48/0.44 (median/IQR, Tb.N; 1/mm^-1), P = 0.002] are lower in Dmax ≤50 Gy compared to controls.

CONCLUSIONS

Radiotherapy dramatically impairs bone turnover in the mandible. Deterioration in microarchitecture only affects bone irradiated with a Dmax of <50 Gy. The 50 Gy value seems to be a critical threshold to where the effects of the radiation is more detrimental.

Should oral foci of infection be removed before the onset of radiotherapy or chemotherapy?

Pretreatment dental screening aims to locate and eliminate oral foci of infection in order to eliminate local, loco-regional, or systemic complications during and after oncologic treatment. An oral focus of infection is a pathologic process in the oral cavity that does not cause major infectious problems in healthy individuals, but may lead to severe local or systemic inflammation in patients subjected to oncologic treatment. As head and neck radiotherapy patients bear a lifelong risk on oral sequelae resulting from this therapy, the effects of chemotherapy on healthy oral tissues are essentially temporary and reversible. This has a large impact on what to consider as an oral focus of infection when patients are subjected to, for example, head and neck radiotherapy for cancer or intensive chemotherapy for hematological disorders. While in patients subjected to head and neck radiotherapy oral foci of infection have to be removed before therapy that may cause problems ultimately, in patients that will receive chemotherapy such, so-called chronic, foci of infection are not in need of removal of teeth but can be treated during a remission phase. Acute foci of infection always have to be removed before or early after the onset of any oncologic treatment.

Effect of α2‑macroglobulin in the early stage of jaw osteoradionecrosis

Advanced osteoradionecrosis (ORN) is one of the most serious complications in patients with head and neck cancer, resulting in poor prognosis. Numerous studies have therefore focused on the pathogenesis and interventions of ORN early stage. The present study aimed to investigate whether α2-macroglobulin (α2M) could prevent early-stage jaw osteoradionecrosis caused by radiotherapy (RT). Following local injection of α2M, a single dose of 30 Gy was delivered to rats for pathological exploration. For 28 days, the irradiated mandible and soft tissues were examined for potential changes. Furthermore, primary human bone marrow mesenchymal stem cells pretreated with α2M followed by 8 Gy irradiation (IR) were also used. Tartrate-resistant acid phosphatase assay, terminal uridine deoxynucleotidyl nick end labeling assay and immunohistochemical staining were performed on irradiated mandibular bone, tongue or buccal mucosa tissues from rats. Cell proliferation was assessed by evaluating the cell morphology by microscopy and by using the cell counting kit-8. Fluorescence staining, flow cytometry and western blotting were conducted to detect the reactive oxygen species level, cell apoptosis and protein expression of superoxide dismutase 2 (SOD2), heme oxygenase-1 (HO-1) and phosphorylated Akt following irradiation. The results demonstrated that α2M attenuated physical inflammation, osteoclasts number and fat vacuole accumulation in mandibular bone marrow and bone marrow cell apoptosis following IR in vivo. Furthermore, α2M pretreatment suppressed the expression of 8-hydroxy-2′-deoxyguanosine in mandibular bone and tongue paraffin embedded sections, which is a marker of oxidative damage, and increased SOD2 expression in mucosa and tongue paraffin embedded sections. The present study demonstrated the efficient regulation of antioxidative enzymes, including SOD2 and heme oxygenase-1, and reduction in oxidative damage by α2M. In addition, in vitro results confirmed that α2M may protect cells from apoptosis and suppress reactive oxygen species accumulation. Overall, the present study demonstrated that α2M treatment may exert some radioprotective effects in early-stage ORN via antioxidant mechanisms, and may therefore be considered as a potential alternative molecule in clinical prophylactic treatments.

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.

Cell therapy stimulates bone neoformation in calvaria defects in rats subjected to local irradiation

BACKGROUND

The purpose of the study was to analyze the effect of cell therapy on the repair process in calvaria defects in rats subjected to irradiation.

METHODS

Bone marrow mesenchymal cells were characterized for osteoblastic phenotype. Calvariae of male Wistar rats were irradiated (20 Gy) and, after 4 weeks, osteoblastic cells were placed in surgically created defects in irradiated (IRC) and control animals (CC), paired with untreated irradiated (IR) and control (C) animals. After 30 days, histological and microtomographic evaluation was performed to establish significant (P < 0.05) differences among the groups.

RESULTS

Higher alkaline phosphatase detection and activity, along with an increase in mineralized nodules, in the IRC, C and CC groups compared to the IR group, confirmed an osteoblastic phenotype. Histology showed impaired bone neoformation following irradiation, affecting bone marrow composition. Cell therapy in the IRC group improved bone neoformation compared to the IR group. Microtomography revealed increased bone volume, bone surface and trabecular number in IRC group compared to the IR group.

CONCLUSION

Cell therapy may improve bone neoformation in defects created after irradiation.

A modified protocol of mandibular osteoradionecrosis induction in rats with external beam radiation therapy

OBJECTIVE

To propose a modified protocol of mandibular osteoradionecrosis induction in rats with external beam radiation therapy.

MATERIAL AND METHODS

A total of 45 male Wistar rats were used in this study. Firstly, 25 rats were divided into 5 groups (n = 5) according to the radiation dose protocol: without irradiation and irradiated with 15 Gy, 20 Gy, 25 Gy, or 30 Gy using a linear accelerator. Secondly, 15 other rats were divided into 3 groups (n = 5) according to the time of extraction of the three right mandibular molars: 7, 10, or 14 days after irradiation of 20 Gy. Lastly, dental extractions were performed in 5 other rats without irradiation (C-E10) for comparison with those of the group of dental extractions 10 days after irradiation (I-E10).

RESULTS

The irradiated animals survived throughout the study period only at single doses of 15 Gy and 20 Gy. The suitable time for dental extractions after irradiation to induce mandibular osteoradionecrosis was defined as 10 days. Macroscopic evaluation of the right hemimandibles showed presence of osteoradionecrosis in I-E10 group and complete gingival healing in C-E10 group.

CONCLUSION

A single radiation dose of 20 Gy focused on head and neck region combined with the extraction of the three mandibular molars 10 days after irradiation constitutes a feasible protocol of mandibular osteoradionecrosis induction in rats with external beam radiation therapy.

CLINICAL RELEVANCE

Establishing a solid and widely available protocol of mandibular osteoradionecrosis induction is essential in the search for methods to prevent this complex disease.

Osteoradionecrosis, an increasing indication for microvascular head and neck reconstruction

Better cancer treatment has led to a steadily growing population of cancer survivors suffering from late adverse effects after cancer treatment. The aim of this study was to investigate whether there has been an increase in free flap reconstruction due to osteoradionecrosis (ORN). A retrospective review was conducted to identify all consecutive head and neck free flap reconstructions performed over an 18-year period (1995-2012) at Karolinska University Hospital. A total of 235 free flaps were identified. Cases were divided into two groups: head and neck cancer reconstructions and ORN reconstructions. A comparison between the two groups showed longer survival (P<0.001) and higher rates of late complications (P<0.001) among ORN cases. ORN as an indication for reconstruction increased over time, from 7.0% of the total number of free flaps performed in 1995-2000, to 15.2% during the period 2001-2006, and to 27.3% in 2007-2012 (P<0.001). This, in accordance with the results of other studies, highlights the importance of the appropriate allocation of resources within the healthcare system to treat this patient group within the steadily increasing population of cancer survivors.

Osteoradionecrosis of the jaws triggered by dental implants placement: A case report

Background

The decision-making process about how to rehabilitate edentulous osseous defects in patients with head and neck cancer history can be complex. Even though, endosseous dental implants could be considered to be the first choice for treating these patients, it is highly important to be aware of the complications that might occur. The aim of this report was to describe the clinical features of mandibular fracture after dental implants placement on a cancer irradiated patient and update the available information about this event.

Case report

The case describes a 70-year-old man, with medical background of radiotherapy in jaw bones to treat a carcinoma in the floor of the mouth and later on in the soft palate and cheek. One week after dental implant surgery, the patient presented a mandibular osteoradionecrosis that healed in 8 months. A fracture on the right side of the body mandible was diagnosed one year after implant placement. Although several options were suggested in order to repair the fracture, the patient did not accept any further treatment despite the callus formation not being radiographically evident. The implant-supported prosthesis is functionally useful for more than 8 years of follow-up without significant problems.

Conclusions

The implant treatment and management of oncologic irradiated patients require special considerations due to the risk of osteoradionecrosis and its possible complications, such as pathologic fracture. It is necessary to provide full information to the patient about risk factors and complications.

Key words:Dental implants, mandibular fracture, osteoradionecrosis jaw, complications, fracture, cancer.

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.

Nomogram model to predict postoperative relapse after mandibular osteoradionecrosis surgery

PURPOSE

Osteoradionecrosis of the mandible (ORNM) is one of the most devastating complications following radiotherapy. Postoperative relapse (POR) occurs with high incidence even if a radical resection is performed. The current investigation was designed to identify prognostic factors for POR and to establish a nomogram model to estimate the risk for the onset of POR of ORNM.

MATERIALS AND METHODS

A retrospective study was conducted in ORNM patients during the period from 2003 to 2016. Predictive factors for POR were preliminarily filtered by Kaplan-Meier analysis and were further confirmed by Cox regression model. A nomogram model was established to predict the risk for the onset of POR, and the performance was estimated by receiver operating characteristic (ROC) and calibration curve. POR was defined as the primary outcome variable and was measured using univariate and multivariate analyses.

RESULTS

A total of 213 patients were analyzed, and the total incidence of POR was 24.4% (52/213). In the Cox regression analysis, radiation doses ≥80 Gy (versus＜80 Gy, OR = 3.528, P＜0.001, 95% CI: 1.759-7.076), location of ORNM (lesion only in mandibular body versus that involving mandibular body, angulus and ramus versus, OR = 2.900, P = 0.007, 95% CI: 1.345-6.253), S classification (S2 versus S0, OR = 8.926, P = 0.001, 95% CI: 2.487-32.036), and surgical treatment (sequestretomy versus ER + reconstruction, OR = 3.299, P = 0.012, 95% CI: 1.294-8.411) were significantly associated with POR. The current nomogram model can effectively evaluate the hazard risk and survival rate of POR. The discrimination capability was tested by the ROC curve with an area under the curve of 0.813, revealing highly predictive abilities. The calibration curve showed sufficient fitness.

CONCLUSION

The current nomogram model was effective in predicting the risk of POR in ORNM patients.