Osteonecrosis of the jaw related to non-antiresorptive medications: a systematic review

Exploring the Impact of Novel Anti-Cancer Therapies on Jaw Osteonecrosis and Other Bones: A Comprehensive Review

Osteonecrosis is a debilitating condition characterized by the loss of blood supply to the bones, leading to bone death. This condition can impact various bones, including the jaw, which significantly affects patients' quality of life by causing difficulties in swallowing, feeding, chewing, and speaking, along with swollen, painful mucous membranes and chronic sinusitis. Osteonecrosis can arise due to treatment with antiresorptive drugs. However, there is a growing number of reports of osteonecrosis following novel targeted anti-cancer treatments, such as tyrosine kinase inhibitors (TKIs) and biological therapies. The pathogenesis of osteonecrosis is linked to the side effects of the antiangiogenic mechanisms of these medications, leading to a disrupted blood flow. Our review aims to examine recent insights into osteonecrosis triggered by new anti-cancer drugs. Most reports focus on the osteonecrosis of the jaw (ONJ); however, we discovered that some authors have described cases of osteonecrosis affecting the femoral head or elbow following novel anti-cancer treatments. Prevention is a key component in managing osteonecrosis. Therefore, a comprehensive risk assessment should always be performed before and during anti-cancer therapy.

Could MRONJ Be Related to Osimertinib Monotherapy in Lung Cancer Patients after Denosumab Suspension?

BACKGROUND

Medication-related osteonecrosis of the jaws is the most frequent complication in patients treated or in therapy with antiresorptive/antiangiogenetic drugs. The list of medications possibly related to MRONJ onset is constantly growing; we aimed to report on a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (Osimertinib) as possibly responsible for bilateral maxillary necrosis onset in the herein-described case.

METHODS

In June 2023, an oncologic patient with two different maxillary bone exposures was referred to our attention. His medical history revealed a two-year Denosumab regimen along with Osimertinib, the latter not suspended before teeth extractions. The clinicians performed a sequestrum removal and bone debridement after three cycles of antibiotic therapy.

RESULTS

Histologic examinations confirmed the clinical diagnosis of MRONJ excluding a metastatic occurrence, while complete mucosal healing was achieved after 15 days.

CONCLUSIONS

The patient suspended Denosumab for more than six months before teeth extraction for MRONJ prevention; hence, failure to discontinue Osimertinib led us to consider it a possible etiological factor. From a literature analysis, only one case has already been published reporting a possible Osimertinib-related occurrence of MRONJ in lung cancer patients. Our case is a further report that could be intended as an alert both for oncologists and dentists to share decisions about the oral management of such patients together, also informing them about this possible risk. Also, this report could trigger in the scientific community the necessity to evaluate further guidelines for similar doubtful cases in which the drug interaction, the mono-suspension, and the possible removable prosthesis-related additional trauma should be considered causes or con-causes.

Relationship between Medication-Related Osteonecrosis of the Jaw and CDK4/6 Inhibitors in Breast Cancer

OBJECTIVE

We aimed to evaluate the use of CDK4/6 inhibitors as a risk factor for medication-related osteonecrosis of the jaw (MRONJ) in a cohort of patients with metastatic breast cancer treated with denosumab.

METHODS

This was a multicentre, retrospective, observational study. All patients with breast cancer treated with denosumab (January 2011-December 2022) were included. The relationship between CDK4/6 inhibitors and MRONJ was analysed.

RESULTS

A total of 243 patients were included, ninety-five (44.2%) of whom used a CDK4/6 inhibitor. There were 21 patients with MRONJ. In patients treated with denosumab without CDK4/6 inhibitors, the incidence of MRONJ and mean time to the occurrence of MRONJ were 6.6% (8/120) and 16.8 months (SD 7.8), respectively; in patients treated with denosumab and CDK4/6 inhibitor, these values were 13.7% (13/95) and 15.4 months (SD 8.7), respectively. The difference in the incidence was not significant (p = 0.085). Among the 19 patients who used abemaciclib, the probability of MRONJ occurrence was significantly higher compared to patients not using CDK4/6 inhibitors (p = 0.0178).

CONCLUSIONS

These results suggest that the incidence of MRONJ in patients with metastatic breast cancer treated with denosumab is higher, and the onset of MRONJ occurs earlier in the presence of CDK4/6 inhibitors. The differences were statistically significant in the patients who used abemaciclib. Given that the use of this combination is very common in routine clinical practice, it would be advisable to carry out larger prospective studies to clarify the risk of this association.

Medication-related osteonecrosis of the jaw: the radiologist's role

In recent decades, the dreaded adverse effect of bisphosphonates, osteonecrosis of the jaw, has been widely reported and described in detail. Osteonecrosis of the jaw consists of the destruction of part of the maxilla as a consequence of these antiresorptive drugs. In recent years, new drugs that can also cause osteonecrosis of the jaw (e.g., some monoclonal antibodies or antiangiogenic drugs) have come on the market. For this reason, the term "bisphosphonate-related osteonecrosis of the jaw" has been replaced with "medication-related osteonecrosis of the jaw (MRONJ). This review aims to describe the radiologic characteristics of MRONJ that, although nonspecific, radiologists need to recognize in the appropriate clinical context.

Pathophysiology of Medication-Related Osteonecrosis of the Jaw-A Minireview

Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious adverse effect of antiresorptive medications administered for control of osseous malignancy, osteoporosis, or other bone metabolic diseases. Despite being reported in the literature two decades ago, MRONJ etiology, pathophysiology, and progression remain largely unknown, and current nonoperative or operative treatment strategies are mostly empirical. Several hypotheses that attempt to explain the mechanisms of MRONJ pathogenesis have been proposed. However, none of these hypotheses alone is able to capture the complex mechanistic underpinnings of the disease. In this minireview, we aim to highlight key findings from clinical and translational studies and propose a unifying model for the pathogenesis and progression of MRONJ. We also identify aspects of the disease process that require further investigation and suggest areas for future research efforts toward calibrating methodologic approaches and validating experimental findings. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Brazilian dental consensus on dental management in hematopoietic stem cell transplantation - Part I - pre-HSCT

The oral involvement in the Hematopoietic Stem Cell Transplantation is well described in the literature. The goal of the dental treatment and management of the oral lesions related to the HSCT is to reduce the harm caused by preexisting oral infection or even the worsening of oral acute/chronic GVHD and late effects. The aim of this guideline was to discuss the dental management of patients subjected to HSCT, considering three phases of the HSCT: pre-HSCT, acute phase, and late phase. The literature published from 2010 to 2020 was reviewed in order to identify dental interventions in this patient population. The selected papers were divided into three groups: pre-HSCT, acute and late, and were reviewed by the SBTMO Dental Committee's members. When necessary, an expertise opinion was considered for better translating the guideline recommendations to our population dental characteristics. This manuscript focused on the pre-HSCT dental management. The objective of the pre-HSCT dental management is to identify possible dental situations that can worsening during the acute phase after the HSCT. Each guideline recommendations were made considering the Dentistry Specialties. The clinical consensus on dental management prior to HSCT provides professional health caregivers with clinical setting-specific information to help with the management of dental problems in patients to be subjected to HSCT.

Incidence and trend of antiresorptive agent-related osteonecrosis of the jaw from 2016 to 2020 in Kure, Japan

We investigated the incidence/trend of osteonecrosis of the jaw by antiresorptive agent dose over a 5-year period in Kure city, Japan. The incidence was 24 times higher among osteoporosis patients with low-dose agents and 421 times higher among cancer patients with high-dose agents than in the population without agents.

PURPOSE

We launched the registry system of osteonecrosis of the jaw (ONJ) cases in 2015 to investigate the trend in ONJ incidence. The purpose of our study was to estimate the ONJ incidence among patients with antiresorptive agent use by dosage and people without antiresorptive agent use in Kure and its trend from 2016 to 2020.

METHODS

From 2016 to 2021, 98 eligible ONJ patients were enrolled. Medication-related ONJ (MRONJ) was diagnosed based on the American Association of Oral and Maxillofacial Surgeons criteria. The annual number of those with and without antiresorptive agents was obtained from the claims database. Antiresorptive agents used for cancer and osteoporosis patients were defined as high- and low-dose medications, respectively.

RESULTS

The annual incidence of high-dose MRONJ was 2305.8 per 100,000 and that of low-dose MRONJ was 132.5 per 100,000, while the ONJ incidence among people without antiresorptive agents was 5.1 per 100,000. The incidence ratio was 23.6 (p < 0.001, 95% confidence interval (CI) 13.3-41.8) among osteoporosis patients who used low-dose antiresorptive agents and 420.6 (p < 0.001, 95% CI 220.8-801.4) among cancer patients who used high-dose agents compared with people who did not use these agents. MRONJ incidence increased from 2016 to 2020, but the incidence of high-dose MRONJ decreased, although this was nonsignificant.

CONCLUSION

We demonstrated the incidence and trend of ONJ by antiresorptive agent dose over a 5-year period in Kure after launching the multiprofession study. This collaborative study for the early detection and prevention of ONJ will continue.

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.

Advances in materials-based therapeutic strategies against osteoporosis

Osteoporosis is caused by the disruption in homeostasis between bone formation and bone resorption. Conventional management of osteoporosis involves systematic drug administration and hormonal therapy. These treatment strategies have limited curative efficacy and multiple adverse effects. Biomaterials-based therapeutic strategies have recently emerged as promising alternatives for the treatment of osteoporosis. The present review summarizes the current status of biomaterials designed for managing osteoporosis. The advantages of biomaterials-based strategies over conventional systematic drug treatment are presented. Different anti-osteoporotic delivery systems are concisely addressed. These materials include injectable hydrogels and nanoparticles, as well as anti-osteoporotic bone tissue engineering materials. Fabrication techniques such as 3D printing, electrostatic spinning and artificial intelligence are appraised in the context of how the use of these adjunctive techniques may improve treatment efficacy. The limitations of existing biomaterials are critically analyzed, together with deliberation of the future directions in biomaterials-based therapies. The latter include discussion on the use of combination strategies to enhance therapeutic efficacy in the osteoporosis niche.

MRONJ in breast cancer patients under bone modifying agents for cancer treatment-induced bone loss (CTIBL): a multi-hospital-based case series

BACKGROUND

Cancer treatment-induced bone loss (CTIBL) is the most common adverse event experienced by patients affected by breast cancer (BC) patients, without bone metastases. Bone modifying agents (BMAs) therapy is prescribed for the prevention of CTIBL, but it exposes patients to the risk of MRONJ.

METHODS

This multicentre hospital-based retrospective study included consecutive non-metastatic BC patients affected by MRONJ related to exposure to low-dose BMAs for CTIBL prevention. Patients' data were retrospectively collected from the clinical charts of seven recruiting Italian centres.

RESULTS

MRONJ lesions were found in fifteen females (mean age 67.5 years), mainly in the mandible (73.3%). The mean duration of BMAs therapy at MRONJ presentation was 34.9 months. The more frequent BMAs was denosumab (53.3%). Ten patients (66.7%) showed the following local risk factors associated to MRONJ development: periodontal disease (PD) in three cases (20%) and the remaining six (40%) have undergone PD-related tooth extractions. One patient presented an implant presence-triggered MRONJ (6.7%). In five patients (33.3%) no local risk factors were observed.

CONCLUSIONS

This is the first case series that investigated BC patients under BMAs for CTIBL prevention suffering from MRONJ. These patients seem to have similar probabilities of developing MRONJ as osteo-metabolic ones. Breast cancer patients under BMAs for CTIBL prevention need a regular prevention program for MRONJ, since they may develop bone metastases and be treated with higher doses of BMAs, potentially leading to a high-risk of MRONJ.

Management of Tooth Extraction in Patients Taking Antiresorptive Drugs: An Evidence Mapping Review and Meta-Analysis

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a well-known severe adverse reaction of antiresorptive, antiangiogenic or targeted therapies, and usually occurs after tooth extraction. This review is aimed at determining the efficacy of any intervention of tooth extraction to reduce the risk of MRONJ in patients taking antiresorptive drugs, and present the distribution of evidence in these clinical questions.

METHODS

Primary studies and reviews were searched from nine databases (Medline, EMBase, Cochrane Library, Scopus, WOSCC, Inspec, KCI-KJD, SciELO and GIM) and two registers (ICTRP and ClinicalTrials.gov) to 30 November 2022. The risk of bias was assessed with the ROBIS tool in reviews, and the RoB 2 tool and ROBINS-I tool in primary studies. Data were extracted and then a meta-analysis was undertaken between primary studies where appropriate.

RESULTS

Fifteen primary studies and five reviews were included in this evidence mapping. One review was at low risk of bias, and one randomized controlled trial was at moderate risk, while the other eighteen studies were at high, serious or critical risk. Results of syntheses: (1) there was no significant risk difference found between drug holiday and drug continuation except for a subgroup in which drug continuation was supported in the reduced incidence proportion of MRONJ for over a 3-month follow-up; (2) the efficacy of the application of autologous platelet concentrates in tooth extraction was uncertain; (3) there was no significant difference found between different surgical techniques in any subgroup analysis; and (4) the risk difference with antibacterial prophylaxis versus control was -0.57, 95% CI -0.85 to -0.29.

CONCLUSIONS

There is limited evidence to demonstrate that a drug holiday is unnecessary (and may in fact be potentially harmful) in dental practice. Primary closure and antibacterial prophylaxis are recommended despite limited evidences. All evidence have been graded as either of a low or very low quality, and thus further high-quality randomized controlled trials are needed to answer this clinical question.

Oral Side Effects in Patients with Metastatic Renal Cell Carcinoma Receiving the Antiangiogenic Agent Pazopanib-Report of Three Cases

Pazopanib is a potent multi-kinase inhibitor that hinders angiogenesis and blocks tumor growth. It has been approved for the treatment of metastatic renal cell carcinoma (mRCC) and advanced soft tissue sarcoma. There is emerging evidence that bleeding is a common adverse effect of pazopanib and other targeted therapies in patients with mRCC. In addition, jaw osteonecrosis related to pazopanib was recently described in the literature. We report three cases of patients with mRCC who developed adverse oral events related to pazopanib. The first patient, treated with pazopanib as monotherapy, presented with gingival bleeding and oral burning sensation. The other two patients receiving pazopanib as monotherapy and pazopanib followed by sunitinib, respectively, presented complaining about mandibular pain; a diagnosis of medication-related osteonecrosis of the jaw (MRONJ) was rendered in both cases. Gingival bleeding and MRONJ may develop as oral side effects of pazopanib use. The cases presented here aim to alert and inform health care professionals about the risk of adverse oral events in patients with mRCC receiving the antiangiogenic agent pazopanib.

Bioinformatic Data Mining for Candidate Drugs Affecting Risk of Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ) in Cancer Patients

Background. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) leads to significant morbidity. Other coadministered drugs may modulate the risk for BRONJ. The present study aimed to leverage bioinformatic data mining to identify drugs that potentially modulate the risk of BRONJ in cancer. Methods. A GEO gene expression dataset of peripheral blood mononuclear cells related to BRONJ in multiple myeloma patients was downloaded, and differentially expressed genes (DEGs) in patients with BRONJ versus those without BRONJ were identified. A protein-protein interaction network of the DEGs was constructed using experimentally validated interactions in the STRING database. Overrepresented Gene Ontology (GO) molecular function terms and KEGG pathways in the network were analysed. Network topology was determined, and ‘hub genes’ with degree ≥2 in the network were identified. Known drug targets of the hub genes were mined from the ‘drug gene interaction database’ (DGIdb) and labelled as candidate drugs affecting the risk of BRONJ. Results. 751 annotated DEGs ( $\log \text{FC}\ge 1.5$ , $p<0.05$ ) were obtained from the microarray gene expression dataset GSE7116. A PPI network with 633 nodes and 168 edges was constructed. Data mining for drugs interacting with 49 gene nodes was performed. 37 drug interactions were found for 9 of the hub genes including TBP, TAF1, PPP2CA, PRPF31, CASP8, UQCRB, ACTR2, CFLAR, and FAS. Interactions were found for several established and novel anticancer chemotherapeutic, kinase inhibitor, caspase inhibitor, antiangiogenic, and immunomodulatory agents. Aspirin, metformin, atrovastatin, thrombin, androgen and antiandrogen drugs, progesterone, Vitamin D, and Ginsengoside 20(S)-Protopanaxadiol were also documented. Conclusions. A bioinformatic data mining strategy identified several anticancer, immunomodulator, and other candidate drugs that may affect the risk of BRONJ in cancer patients.

Use of multikinase inhibitors/lenvatinib concomitant with antiresorptive therapy for bone metastases from radioiodine-resistant differentiated thyroid cancer

Bone is the second most common distant metastasis site in differentiated thyroid cancer (DTC) and is normally associated with the presence of other metastases, which are usually radioiodine‐resistant. The presence of bone metastasis (BM) determines low survival and greater morbidity due to the frequency of skeletal‐related events (SREs), which can be a serious complication of BM. There is evidence that antiresorptive therapy (AT) reduces SREs in other solid tumors, but not yet in DTC BM, for which data are scant. The same is true for systemic therapy with multikinase inhibitors (MKIs). In general, the results for MKI use are well known, although the effect on BM has rarely been evaluated. While MKIs are indicated in current clinical practice guidelines, studies evaluating the benefits and risks of concomitant treatment with MKIs and AT are lacking, and the available data come from small samples in retrospective studies. The objective of this article is to review the latest evidence for concomitant MKIs and AT.

Bone is a common distant metastasis in differentiated thyroid cancer, that is associated with the presence of other metastases, low survival and high morbidity. There is evidence that antiresorptive therapy and multikinase inhibitors reduce skeletal‐related events in other solid tumors, but studies evaluating the benefits and risks of concomitant treatment are lacking in differentiated thyroid cancer. This article reviews the latest evidence.

Medication-related osteonecrosis of the jaw in cancer patients: Case series and review of the current literature

Currently, a large proportion of cancer patients are treated with bone modifying agents (BMA). In this regard, the increase in the prescription of these drugs has lead to concerns in the increment of osteonecrosis of the jaws. This article describes four patients with BMA cancer treatments requested dental evaluation at our institution due to pain and swelling of the mandibular bone after tooth extraction, tooth loss, or unknown risk factor. Oral and radiographic evaluation reveals Medication-related osteonecrosis of the jaw (MRONJ) at different clinical stages according to the American Association of Oral and Maxillofacial Surgeons (AAOMS) classification. Some patients underwent abscess drainage, oral cleaning and antibiotic therapy with complete recovery. Follow-up showed treatment success in all patients. That is why we emphasize the importance of early establishment of appropriate treatment and emphasize the avoidance of dental procedures during BMA therapy.

Medication-related osteonecrosis of the jaw after dental clearance: Prevalence in an oncology center

Objective

Study design

Results

Conclusion

American Association of Oral and Maxillofacial Surgeons' Position Paper on Medication-Related Osteonecrosis of the Jaws-2022 Update

Strategies for management of patients with, or at risk for, medication-related osteonecrosis of the jaws (MRONJ) - formerly referred to as bisphosphonate-related osteonecrosis of the jaws (BRONJ)-were set forth in the American Association of Oral and Maxillofacial Surgeons (AAOMS) position papers in 2007, 2009 and 2014. The position papers were developed by a committee appointed by the AAOMS Board of Trustees and comprising clinicians with extensive experience in caring for these patients, as well as clinical and basic science researchers. The knowledge base and experience in addressing MRONJ continues to evolve and expand, necessitating modifications and refinements to the previous position papers. Three members of the AAOMS Committee on Oral, Head, and Neck Oncologic and Reconstructive Surgery (COHNORS) and three authors of the 2014 position paper were appointed to serve as a working group to analyze the current literature and revise the guidance as indicated to reflect current knowledge in this field. This update contains revisions to diagnosis and management strategies and highlights the current research status. AAOMS maintains that it is vitally important for this information to be disseminated to other relevant healthcare professionals and organizations.

Oral Complications in Cancer Patients–Medication-Related Osteonecrosis of the Jaw (MRONJ)

Medication-Related Osteonecrosis of the Jaw (MRONJ) was first reported in 2003. Despite the progress in the understanding of this oral complication in cancer patients for the past 18 years, there is still discussion about the best way to define MRONJ, prevent the complication, how to diagnose, and the options of treatment available. The initial reports associated MRONJ to bisphosphonates and denosumab, medications that work as bone-modifying agents. Later, other agents such as the antiangiogenics, have also been reported to cause the oral complication, either alone or in combination with antiresorptives. Initially, these medications were prescribed to patients with osteoporosis and cancers patients with bone metastasis. Today, because of the effect of the medications in the bone remodeling system, patients with several other diseases such as giant cell tumors, rheumatoid arthritis, Paget's disease of bone, fibrous dysplasia, osteogenesis imperfecta, are managed with these medications, significantly increasing the population of individuals at risk for developing MRONJ. This mini review focused on the cancer patient. It updates the dental clinician on the recent scientific literature about MRONJ and provides information on how to diagnose and manage patients being treated with these medications, suggests protocols to prevent the development of MRONJ, and present ways to manage those patients who develop the oral complication.

Osteonecrosis of the Jaw and Antiresorptive Agents in Benign and Malignant Diseases: A Critical Review Organized by the ECTS

CONTEXT

Antiresorptive therapy significantly reduces fracture risk in patients with benign bone disease and skeletal-related events (SREs) in patients with bone metastases (BM). Osteonecrosis of the jaw (ONJ) is a rare but severe condition manifested as necrotic bone lesion or lesions of the jaws. ONJ has been linked to the use of potent antiresorptive agents, termed medication-related ONJ (MRONJ).

OBJECTIVE

We aimed to identify the differences various aspects of MRONJ among distinct patient categories and provide recommendations on how to mitigate the risk and optimally manage MRONJ in each of them.

METHODS

A working group of the European Calcified Tissue Society (ECTS) and 2 experts performed an updated detailed review of existing literature on MRONJ incidence, characteristics, and treatment applied in bone diseases with variable severity of skeletal insult, ranging from osteoporosis to prevention of cancer treatment-induced bone loss and SREs in cancer patients with BM.

RESULTS

The risk for MRONJ is much higher in patients with advanced malignancies compared to those with benign bone diseases because of the higher doses and more frequent administration of antiresorptive agents in individuals with compromised general health, along with coadministration of other medications that predispose to MRONJ. The overall risk for MRONJ is considerably lower than the benefits in all categories of patients.

CONCLUSION

The risk for MRONJ largely depends on the underlying bone disease and the relevant antiresorptive regimen applied. Physicians and dentists should keep in mind that the benefits of antiresorptive therapy far outweigh the risk for MRONJ development.

The preventive care of medication-related osteonecrosis of the jaw (MRONJ): a position paper by Italian experts for dental hygienists

PURPOSE

The prevention and early diagnosis of medication-related osteonecrosis of the jaw (MRONJ) is fundamental to reducing the incidence and progression of MRONJ. Many in the field believe that dental hygienists should play an integral role in primary and secondary MRONJ prevention. However, to date, very few publications in the literature have proposed standardised MRONJ protocols, which are dedicated to dental hygienists. The aim of this study was to provide guidance to the health care providers managing MRONJ.

METHODS

The expert opinion in this study was developed by dental hygienists from the main Italian technical-scientific associations (Italian Dental Hygienists Association, AIDI and National Union of Dental Hygienists, UNID) and authors of the latest Italian recommendations regarding MRONJ from the field of dentistry and maxillofacial surgery.

RESULTS

The oral care protocol outlined in this position paper is focused on the role of dental hygienist in patients at risk or affected by MRONJ, and it regards 3 main issues: primary prevention, secondary prevention and supporting the treatment of MRONJ. Each issue contains easy-to-apply indications and procedures, as described by the authors, regarding the role of the dental hygienist.

CONCLUSION

Referring to the main issues under consideration (primary prevention, secondary prevention and the treatment of MRONJ), a clinical examination of periodontal tissue is critical in preventing MRONJ. It is the opinion of the authors of this study that the application of a periodontal screening score is fundamental in defining personalised strategies for patients at risk of MRONJ. By means of these basic procedures, a protocol for assisting the health care provider and the presentation of a practical approach for patients at risk or affected by MRONJ are described in this study.

Bone Targeting Agents in Patients with Prostate Cancer: General Toxicities and Osteonecrosis of the Jaw

Introduction: Bone metastases are the most frequent site of secondary localization of prostate cancer (PCa) and are present in about 90% of cases of advanced disease. Consequently, an adequate management of bone involvement is of pivotal importance in the therapeutic approach and skeletal-related events (SREs) need to be closely monitored and promptly assessed and treated. Bone targeting agents (BTAs), consisting in bisphosphonates and denosumab, are an essential part of the treatment of metastatic prostate cancer that accompanies systemic treatments throughout the most part of the history of the disease. Activity and safety of bone targeting agents: These treatments are correlated to better outcomes in terms of reduction of SREs and, in metastatic castration resistant setting, of increased overall survival (OS), but several important adverse events have to be managed and prevented. Of these, osteonecrosis of the jaw (ONJ) is extremely invalidating and should be managed with a special attention. Discussion: The role of BTAs in prostate cancer is pivotal throughout many stages of the disease, but several toxicities should be quickly recognized and treated. We aim at recollecting evidence on clinical benefit of BTAs, common and specific toxicities, and explore the pathophysiology and clinical aspects of osteonecrosis of the jaw. We present a review of the literature to report the role of the different types of bone targeting agents in the management of prostate cancer with bone metastases with a particular focus on common toxicities and ONJ to recollect current evidences on the activity of these compounds and the correct management of their adverse events.

The presenting dental status of solid tumours with bone metastases requiring bone-targeting agents - part 4: miscellaneous cancers

This article discusses relevant information for the dental sector regarding metastatic cancers beyond breast and prostate cancer. Typically, tumour sites such as lung, renal, colorectal, gastrointestinal, thyroid, hepatic and pancreatic cancers are increasingly being referred for bone-targeting agents upon evidence of bone metastases.The current article explores the presenting dental status of these tumour groups on the background of survival outcomes. In addition, the article provides insight towards the complexity in achieving 'dental fitness' and whether 'dental stability' could be an alternative to consider via palliative dentistry in certain cases.

Medication-Related Osteonecrosis of the Jaw Associated in a Patient Treated With Etanercept

ABSTRACT

Medication-related osteonecrosis of the jaws (MRONJ) is defined as a pathologic condition affecting the maxillary and mandibular bones arising subsequently to pharmacological treatment with antiresorptive and antiangiogenic drugs.In this case report, the occurrence of MRONJ is described in a 66-year-old female patient affected by rheumatoid arthritis and treated with Etanercept, a Tumor Necrosis Factor (TNF)-α inhibitor. The patient developed a mandibular MRONJ following the extraction of teeth 3.4 and 3.5. The patient was then treated with conservative surgery of the necrotic bone. At 12-month follow-up complete resolution was observed. According to the data presented, the evaluation of the effects of new immunosuppressive biological therapies on the oral cavity appears of utmost importance in preventing the development of MRONJ. Although the risk related to TNF-α inhibitors has not been quantified yet, the clinician should be aware of the potential adverse effects on the oral cavity.

[Management of medication-related osteonecrosis of the jaw-a review of recent study results in comparison to established strategies]

Hintergrund

Antiresorptiva gehören weltweit zu den am häufigsten applizierten Arzneimitteln. Ihr Haupteinsatzbereich liegt in der Osteologie und Onkologie. Trotz allgemein guter Verträglichkeit treten bei Patienten unter Therapie unerwünschte Arzneimittelwirkungen (UAW) auf. Eine spezifische UAW im Bereich der Kiefer ist die sog. medikamentenassoziierte Osteonekrose („medication-related osteonecrosis of the jaw“, MRONJ) der Kiefer.

Ziel der Arbeit

Diese Arbeit stellt neuesten Entwicklungen in Ätiologie, Diagnostik und Therapie der MRONJ im Vergleich zu bereits bestehenden Erkenntnissen zusammen.

Methodik

Es wurde eine systematische Literaturübersicht der Jahre 2016–2021 zu diesem Thema durchgeführt. Prospektive Therapiestudien, Diagnostikstudien mit Vergleichsgruppe und innovative Studien zur Pathogenese der MRONJ wurden eingeschlossen und nach den MINORS-Kriterien („methodological index for non-randomized studies“) bewertet.

Ergebnisse und Diskussion

Die MRONJ tritt bei ca. 2–12 % der Patienten, die aus onkologischer Indikation mit Antiresorptiva behandelt werden, auf (osteologische Indikation ca. 0,1–1 %). Die Therapie der MRONJ sollte frühzeitig und operativ erfolgen. Die Heilungsrate ist bei einem operativen Therapieansatz mit über 85 % sehr gut.

Non-antiresorptive drugs associated with the development of medication-related osteonecrosis of the jaw: a systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review was to provide evidence related to the association between non-antiresorptive medications and MRONJ.

MATERIALS AND METHODS

The following three electronic databases were screened: PubMed, EMBASE, and Web of Science from December 2020 until April 2021. Two reviewers independently performed the study selection, data extraction, and quality assessment of the included studies. The Newcastle-Ottawa Scale (NOS) was used for assessing the risk of bias. A meta-analysis was performed for assessing the relationship between MRONJ and non-antiresorptive medications.

RESULTS

The search strategy retrieved 996 articles. Following removal of duplicates, title, and abstract screening and full-text reading, 58 publications were eligible to be included in the review. A total of 867 cases of MRONJ were included (33% female, 55% male, 12% no gender reported). The mean age of the patients when MRONJ was diagnosed was 61 years (range 19-100 years) and the average time of diagnosis was 10 months following non-antiresorptive drug therapy. Patients with a history of corticosteroids (0.61, 95% CI 0.39, 0.82, p =  < 0.001) and chemotherapy (0.59, 95% CI 0.51, 0.67, p =  < 0.001) showed the highest significant effect size (ED) compared to the control group for MRONJ occurrence.

CONCLUSION

A significant association existed between MRONJ and non-antiresorptive drugs. However, considering limited evidence, findings should be interpreted with caution.

CLINICAL RELEVANCE

The non-antiresorptive drugs might allow the dentist to apply the principle of "drug holiday" following concurrence from the drug prescribing clinician.

PROSPERO REGISTRATION NUMBER

CRD42020173891.

Preclinical models of medication-related osteonecrosis of the jaw (MRONJ)

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe adverse event affecting patients with cancer and patients with osteoporosis who have been treated with powerful antiresorptives (pARs) or angiogenesis inhibitors (AgIs). pARs, including nitrogen-containing bisphosphonates (N-BPs; e.g., zoledronic acid, alendronate) and anti-RANKL antibodies (e.g., denosumab), are used to manage bone metastases in patients with cancer or to prevent fragility fractures in patients with osteoporosis. Though significant advances have been made in understanding MRONJ, its pathophysiology is still not fully elucidated. Multiple species have been used in preclinical MRONJ research, including the rat, mouse, rice rat, rabbit, dog, sheep, and pig. Animal research has contributed immensely to advancing the MRONJ field, particularly, but not limited to, in developing models and investigating risk factors that were first observed in humans. MRONJ models have been developed using clinically relevant doses of systemic risk factors, like N-BPs, anti-RANKL antibodies, or AgIs. Specific local oral risk factors first noted in humans, including tooth extraction and inflammatory dental disease (e.g., periodontitis, periapical infection, etc.), were then added. Research in rodents, particularly the rat, and, to some extent, the mouse, across multiple laboratories, has contributed to establishing multiple relevant and complementary preclinical models. Models in larger species produced accurate clinical and histopathologic outcomes suggesting a potential role for confirming specific crucial findings from rodent research. We view the current state of animal models for MRONJ as good. The rodent models are now reliable enough to produce large numbers of MRONJ cases that could be applied in experiments testing treatment modalities. The course of MRONJ, including stage 0 MRONJ, is characterized well enough that basic studies of the molecular or enzyme-level findings in different MRONJ stages are possible. This review provides a current overview of the existing models of MRONJ, their more significant features and findings, and important instances of their application in preclinical research.

Medication-Related Osteonecrosis of the Jaw in Patients Treated Concurrently with Antiresorptive and Antiangiogenic Agents: Systematic Review and Meta-Analysis

Introduction

Medication-related osteonecrosis of the jaws (MRONJ) is a known adverse event related to the use of antiresorptive (AR) drugs. More recently, an association between antiangiogenic (AA) drugs and MRONJ has been suggested. This review aimed to investigate the overall prevalence and relative risk of MRONJ in patients treated concurrently with AA and AR agents in comparison with a single AA or AR drug.

Methods

A review protocol was registered with PROSPERO (ID: CRD42020214244). A systematic literature search, study selection, quality assessment, and data extraction were carried out following PRISMA guidelines. Random-effects meta-analysis models were used to summarize relative estimates for the outcomes, namely prevalence and relative risk of MRONJ. Exposure variable included type of drug, specifically AA and AR agents administered either concurrently or individually.

Results

Eleven studies were included in the final qualitative and quantitative syntheses. The overall pooled weighted prevalence of MRONJ with concurrent AA-AR drugs was 6% (95% CI: 3–8%), compared with 0% (95% CI: 0–0%) for AA only and 5% (95% CI: 0–10%) for AR only. However, high heterogeneity was noted among included studies. Retrospective cohort studies showed a higher pooled prevalence of 13% (95% CI: 10–17%) for concurrent AA-AR therapy. The pooled risk ratio for MRONJ revealed a risk with concurrent AA-AR drugs 2.57 times as high as with AR only (95% CI: 0.84–7.87); however, this difference was not statistically significant. Concurrent AA-AR drugs had a risk for MRONJ 23.74 times as high as with AA only (95% CI: 3.71–151.92).

Conclusions

High-quality, representative studies are needed for accurate estimation of relative risk of MRONJ with concurrent AA and AR therapy.

Cancer Patients at Risk for Medication-Related Osteonecrosis of the Jaw. A Case and Control Study Analyzing Predictors of MRONJ Onset

The goal of this investigation was to identify potential risk factors to predict the onset of medication-related osteonecrosis of the jaw (MRONJ). Through the identification of the multiple variables positively associated to MRONJ, we aim to write a paradigm for integrated MRONJ risk assessment built on the combined analysis of systemic and local risk factors. The characteristics of a cohort of cancer patients treated with zoledronic acid and/or denosumab were investigated; beyond the set of proven risk factors a new potential one, the intake of new molecules for cancer therapy, was addressed. Registered data were included in univariate and multivariate logistic regression analysis in order to individuate significant independent predictors of MRONJ; a propensity score-matching method was performed adjusting by age and sex. Univariate logistic regression analysis showed a significant effect of the parameters number of doses of zoledronic acid and/or denosumab (OR = 1.03; 95% CI = 1.01–1.05; p = 0.008) and chemotherapy (OR = 0.35; 95% CI = 0.17–0.71; p = 0.008). The multiple logistic regression model showed that breast, multiple myeloma, and prostate cancer involved a significantly higher risk compared to lung cancer; a significant effect of the combined variables number of doses of zoledronic acid and/or denosumab (OR = 1.03; 95% CI = 1.01–1.06); p-value = 0.03) and exposure to novel molecule treatment (OR = 34.74; 95% CI = 1.39–868.11; p-value = 0.03) was observed. The results suggest that a risk assessment paradigm is needed for personalized prevention strategies in the light of patient-centered care.

Different Presentation and Outcomes in the Surgical Treatment of Advanced MRONJ in Oncological and Nononcological Patients Taking or Not Corticosteroid Therapy

Medication-related osteonecrosis of the jaw (MRONJ) is a severe side effect caused by antiangiogenic antiresorptive drugs used to treat various oncological and non oncological diseases. The clinical and radiological characteristics of MRONJ depend on the type of causative drug, the time of administration, and its dosage. Proven systemic risk factors like anemia, uncontrolled diabetes, corticosteroid therapy, and chemotherapy in neoplastic diseases (e.g., high doses of methotrexate up to 30 mg daily) significantly increase the chances of acquiring MRONJ. The risk factors themselves can affect treatment outcomes. Although the main scientific societies have recently disseminated good practice rules on the patient's prevention, diagnosis, and management, there are still no guidelines on shared therapeutic strategies. In general, if conservative treatment fails, surgical treatment is considered, including local debridement, osteoplasty, and marginal or segmental osteotomy. In literature, cohorts of heterogeneous patients with MRONJ have been analyzed for a long time, resulting in a lack of uniformity of information and difficulties interpreting the data. According to the American Association of Oral and Maxillofacial Surgeons criteria, this retrospective study evaluates the surgical treatment outcomes of 64 patients with stage II-III MRONJ, evaluated at the Department of Maxillofacial Surgery of the University of Turin (Italy). The first objective of this retrospective study is to evaluate treatment results for stages II-III in all cases; the second objective is to evaluate the same results by dividing the sample into different cohorts of patients: first, based on the underlying pathology, i.e., oncological and non oncological, and secondly, based on the drug or combination of drugs they took.

Oral Complications of Head and Neck Cancer Therapy

Current therapies for Head and Neck cancer treatment are extremely advanced. Though, they cause oral complications which have deleterious effects on basic life functions, affect oral and overall health, may lead to significant morbidity and treatment discontinuation and have an impact on survivorship and quality of life. As new therapies are introduced, a new spectrum of oral complications is rising, compromising the mucosal integrity and the salivary function, that may not be recognized, reported and treated properly. Oral complications, often permanent and extremely painful, may include mucositis, xerostomia, dysgeusia, infections, trismus and fibrosis, risk of dental disease and necrosis of the jaw, neurosensory disorders and when targeted therapies and immunotherapy are involved, aphthoid and lichenoid lesions can also be reported. Increased awareness is required for the prevention and management of these complications, which can be best provided by a multidisciplinary team.

Local RANKL delivery improves socket healing in bisphosphonate treated rats

Medication related osteonecrosis of the Jaws (MRONJ) is a severe complication of antiresorptive and anti-angiogenic medications. Osteoclast inhibition is central in MRONJ pathogenesis. Here, we investigated if local application of RANKL (a key molecule in osteoclast activation) could enhance osteoclast generation and improve extraction socket healing in the presence of bisphosphonates. Thirty Wistar-Han rats received one saline or 66 μg/kg zoledronate (ZA) i.p. dose before surgery. A week later, mandibular molars were extracted bilaterally. Collagen tapes infused with water or RANKL were placed in the extraction sockets of 60 hemimandibles of veh (veh/RANKL-, veh/RANKL+) or ZA treated rats (ZA/RANKL-, ZA/RANKL+). Rats were euthanized 3 or 12 days after surgery. Animals euthanized at 12 days received two additional veh or ZA injections. Clinical, radiographic and histologic assessments were performed. Visually, at the 3-day timepoint, no sockets demonstrated complete healing. At the 12-day timepoint, sockets of veh/RANKL- and veh/RANKL+ rats showed intact mucosa, while mucosal defects were noted in ZA/RANKL- rats. Importantly, ZA/RANKL+ sockets showed absence of bone exposure. RANKL delivery increased bone healing in the ZA/RANKL+ sites 12 days after extraction compared to the ZA/RANKL- sites. Histologically, at the 3-day timepoint, ZA/RANKL- sockets demonstrated extensive bone exposure and osteonecrosis. In contrast, ZA/RANKL+ rats showed granulation tissue coverage and significantly reduced osteonecrosis, similar to the veh groups. Importantly, in the ZA/RANKL+ group, osteoclasts attached to the bone surface and osteoclast numbers were higher compared to ZA/RANKL- sites. At the 12-day timepoint, persistent osteonecrosis and bone exposure were detected in the sockets of ZA/RANKL- animals. Contrary, ZA/RANKL+ rats demonstrated socket epithelialization and reduced osteonecrosis. Significantly more total and bony attached osteoclasts persisted in the ZA/RANKL+ vs the ZA/RANKL- group. We present a novel approach towards improving socket healing, in the presence of ZA, by enhancing osteoclastic numbers and attachment through local RANKL application. Our approach is clinically applicable and could improve treatment outcomes of patients on high-dose ZA therapy.

Progression of Cabozantinib-Related Osteonecrosis Mimicking Metastases on Bone Scan

ABSTRACT

Patient was a 73-year-old woman with metastatic renal cell carcinoma. Bone scan showed multifocal bone metastases. The patient received cabozantinib treatment for more than 1 year. On the follow-up bone scan, the previously biopsy-proven left pelvic bone lesion has improved, whereas the right maxillary lesion showed increased extent and intensity of abnormal radiotracer uptake. Given the different change pattern of these lesions, the right maxillary lesion was further evaluated. Biopsy results confirmed devitalized bone with bacterial colonies overgrowth and without tumor cell, suggestive of medication-related osteonecrosis.

Bisphosphonates in Dentistry – State of the Art

Bisphosphonates remain the most used and most effective drugs for the treatment of systemic bone diseases followed by bone resorption. Although their side effects in a form of alveolar bone osteonecrosis have been reported, bisphosphonates have a potential of being used in the treatment of the most common oral diseases followed by alveolar bone resorption such as peri-implantitis, periapical lesions, and periodontitis. The aim of this article was to review the most recent research regarding the use of bisphosphonates in the field of dentistry. The results of studies indicate that bisphosphonate use in the treatment of peri-implantitis, periapical lesions, and periodontitis can reduce alveolar bone resorption and contribute to bone preservation. However, the most beneficial way of their application in the treatment of these oral diseases remain to be determined.

Clinical considerations for medication-related osteonecrosis of the jaw: a comprehensive literature review

Background

Medication-related osteonecrosis of the jaw (MRONJ), which was first reported as bisphosphonate-related osteonecrosis of the jaw (BRONJ) in bisphosphonate users, is a rare but severe soft and hard tissue disease induced by several types of medications. There has been a deluge of information about MRONJ, such as epidemiology, risk factors, clinical recommendations for dental treatment to prevent it, and treatment strategies in medication-prescribed users. The aim of this study was to comprehensively review recent articles and provide the current scientific information about MRONJ, especially clinical considerations or recommendations for dental treatment to prevent its occurrence.

Materials and methods

The current literature review was mainly based on 14 systematic reviews with or without meta-analysis, 4 position papers, 1 consensus statement, 1 clinical guideline, and 2 clinical reviews regarding MRONJ after a PubMed database and manual searches according to inclusion and exclusion criteria. Moreover, 53 articles were selected by manual search in regard to all references from selected articles and other articles identified on the PubMed search, irrespective of publication date, and inclusion and exclusion criteria.

Results

The incidence and prevalence of MRONJ are relatively low, although they are clearly higher in cancer patients receiving high-dose antiresorptive agents or angiogenesis inhibitors rather than osteoporosis patients receiving oral bisphosphonates or denosumab. There are many types of local, systemic, and other risk factors for the development of MRONJ. Clinical recommendations are provided for each clinical situation of patients to prevent MRONJ. There are also treatment strategies for MRONJ in each stage.

Conclusions

General dentists should perform appropriate dental treatment to prevent MRONJ in the patients prior to or when receiving medications that could induce MRONJ. Moreover, there are treatment strategies for MRONJ in each stage that oral surgeons could follow. Adequate and updated clinical information regarding MRONJ based on scientific data is required whenever possible.

p300/CBP inhibitor A-485 inhibits the differentiation of osteoclasts and protects against osteoporotic bone loss

Osteoporosis is one of the most common metabolic bone diseases among pre- and post-menopausal women. Despite numerous advances in the treatment of osteoporosis in recent years, the outcomes remain poor due to severe side effects. In this study, we investigated whether A-485, a highly selective catalytic p300/CBP inhibitor, could attenuate RANKL-induced osteoclast differentiation and explored the underlying molecular mechanisms. The protective role of A-485 in osteoporosis was verified using a mouse model of ovariectomy (OVX)-induced bone loss and micro-CT scanning. A-485 inhibited RANKL-induced osteoclast differentiation in vitro by reducing the number of tartrate-resistant acid phosphatase-positive osteoclasts without inducing significant cytotoxicity. In particular, A-485 dose-dependently disrupted F-actin ring formation and downregulated the expression of genes associated with osteoclast differentiation, such as CTSK, c-Fos, TRAF6, VATPs-d2, DC-STAMP, and NFATc1, in a time- and dose-dependent manner. Moreover, A-485 inhibited the RANKL-induced phosphorylation of MAPK pathways and attenuated OVX-induced bone loss in the mouse model while rescuing the loss of bone mineral density. Our in vitro and in vivo findings suggest for the first time that A-485 has the potential to prevent postmenopausal osteoporosis and could therefore be considered as a therapeutic molecule against osteoporosis.

Choosing the Right Partner for Medication Related Osteonecrosis of the Jaw: What Central European Dentists Know

Medication-related osteonecrosis of the jaw (MRONJ) is a side effect of antiresorptive drugs. In this online survey, the awareness and knowledge of dentists regarding MRONJ was evaluated, and potential implications for oncologists are discussed. Questionnaires were emailed to dentists from Germany, Austria, Switzerland, and South Tyrol to evaluate disease-related knowledge and management. In addition to the overall score, a separate score was calculated for knowledge (maximum score: 15 points) and management (maximum score: 6 points) questions, and 1197 valid replies with completed questionnaires were received. The mean overall score was 10.45 ± 3.97 points, the mean knowledge score was 7.68 ± 3.05 points, and the mean management score was 2.76 ± 1.77 points. Factors influencing the outcome of the overall score were age, specialization, continuous professional education, and the number of dental screening exams in patients before antiresorptive therapy. Due to the considerable lack of knowledge regarding MRONJ among dentists, MRONJ patients and subjects at risk should be guided towards specialists for dental screening, treatment, and follow-up. This is important from an oncologic point of view to avoid any delay for treatment start of antiresorptives, and to reveal a potentially emerging osteonecrosis at an early stage, thus, avoiding the need for interruption or even cancellation of antiresorptive therapy.

Human amniotic membrane: an improvement in the treatment of Medication-related osteonecrosis of the jaw (MRONJ)? A case-control study

The aim of this article is to report the results obtained by the use of HAM in surgical wound healing and the reduction of relapse in patients affected by Medication-related osteonecrosis of the jaw (MRONJ).The study involved patients with the diagnosis of MRONJ, surgically treated between October 2016 and April 2019, in a case-control setting. Enrolled patients were randomly divided into 2 groups. One group will be treated with resective surgery and with the insertion of HAM patch (Group A), while the second group had been treated exclusively with resective surgery (Group B).The patients underwent MRONJ surgical treatment with the placement of amniotic membrane patches at the wound site. Data regarding the long-term complications/functions were evaluated at 3, 6, 12, and 24 months after surgery. Pain measurements were performed before the intervention (T0), 7(T1) and 30(T2) days after surgery. 49 patients were included in the study. 2 patients of GROUP A after 30 days since they were surgically treated showed persistent bone exposure. 5 patients of group B demonstrated a lack of healing of the surgical wound with the persistence of bone exposed to 30 days after surgery. Statistical analysis ruled out any difference in OUTCOME (relapse) between GROUP A and B (p = 0.23). However, the Fisher test highlighted a significant difference between the use of HAM and only surgical treatment in pain at rest (p = 0.032). The use of amniotic membrane implement the patient's quality of life and reduce pain perception. has a learning curve that is fast enough to justify its routine use.

Therapeutic Approach in the Treatment of Medication-Related Osteonecrosis of the Jaw: Case Series of 3 Patients and State of the Art on Surgical Strategies

BACKGROUND

Bisphosphonates and receptor activator of nuclear factor kappa-B ligand inhibitors are currently the most widely used antiresorptive therapies in bone metabolism diseases treatment. Unfortunately they can evoke medication-related osteonecrosis of the jaws. The present case series study proposes to evaluate clinical features, evolution and the surgical therapeutic approaches in three patients affected by medication-related osteonecrosis of the jaw and to review the state of art regarding the management of this complication in light of the most recent literature.

METHODS

Three cases of medication-related osteonecrosis of the jaws are discussed, two related to bisphosphonates therapy (ibandronic acid) and one due to denosumab.

RESULTS

All three patients were aged female and had probably a dental trigger agent. The lesions located in posterior mandible were treated in one case with the surgical approach alone and, in the other case, with surgical approach associated with Erb-YAG laser. The lesion related to denosumab was treated with surgical approach and platelet rich fibrin application. A complete healing was always achieved.

CONCLUSIONS

Dentists should be aware of the potential risk of developing medication-related osteonecrosis of the jaws for patients who take or had taken antiresorptive drugs. The side effects of denosumab and bisphosphonates are partly overlapping and currently there is still no consensus about the therapeutic surgical options. Prevention and early detection of the lesions should be the primary strategy.

Preventing or controlling periodontitis reduces the occurrence of osteonecrosis of the jaw (ONJ) in rice rats (Oryzomys palustris)

INTRODUCTION

Osteonecrosis of the jaw (ONJ) is an adverse event that requires association of both systemic risk factors, such as powerful anti-resorptives (pARs; e.g. zoledronic acid [ZOL]), and local oral risk factors (e.g. tooth extraction, periodontitis). Whereas optimal oral health prior to initiate pARs is recognized as critically important for minimizing ONJ risk, the efficacy of preventive/maintenance measures in patients who are taking pARs is understudied. Rice rats fed a standard diet (STD), rich in insoluble fiber, develop localized periodontitis. STD-rats with localized periodontitis treated with ZOL for 18-24 wk develop ONJ. Hence, we hypothesized that controlling/preventing localized periodontitis in the ZOL-treated rats, reduces ONJ occurrence.

METHODS

We used two approaches to attempt reducing periodontitis prevalence: 1) periodontal cleaning (PC); and 2) replacing the STD-diet with a nutritionally-equivalent diet high in soluble fiber (SF). 75 four-week-old male rats were weight-randomized into five groups (n = 15) in a 24-week experiment. Three groups ate the STD-diet and two the high SF-diet. STD-diet groups received intravenous (IV) vehicle (VEH) q4wks (STD + VEH), 80 μg/kg ZOL q4wks IV (STD + ZOL), or ZOL plus PC q2wks (STD + ZOL + PC). The SF-diet groups received VEH (SF + VEH) or ZOL (SF + ZOL). Jaws were processed for histopathology and evaluated for ONJ prevalence and tissue-level periodontitis.

RESULTS

1) 40% of STD + VEH rats developed maxillary localized periodontitis with no ONJ; 2) 50% of STD + ZOL rats developed ONJ; 3) 7% of STD + ZOL + PC rats developed ONJ (p < 0.01 vs. STD + ZOL); and 4) one SF + ZOL rat developed localized periodontitis, and no SF + VEH or SF + ZOL rats developed ONJ (p < 0.001 vs. STD + ZOL).

CONCLUSIONS

1) Periodontal cleaning in ZOL-treated rats decreases localized periodontitis severity and reduces ONJ prevalence; and 2) feeding a SF-diet to ZOL-treated rats reduces both incidence of localized periodontitis and ONJ. Our data indicates strong oral microbial community shifts according to oral health condition and trends in the shifts associated with diet.

Medication-Related Osteonecrosis of the Jaw (MRONJ): Are Antiresorptive Drugs the Main Culprits or Only Accomplices? The Triggering Role of Vitamin D Deficiency

Osteonecrosis of the jaw (ONJ) is a severe clinical condition characterized mostly but not exclusively by an area of exposed bone in the mandible and/or maxilla that typically does not heal over a period of 6-8 weeks. The diagnosis is first of all clinical, but an imaging feedback such as Magnetic Resonance is essential to confirm clinical suspicions. In the last few decades, medication-related osteonecrosis of the jaw (MRONJ) has been widely discussed. From the first case reported in 2003, many case series and reviews have appeared in the scientific literature. Almost all papers concerning this topic conclude that bisphosphonates (BPs) can induce this severe clinical condition, particularly in cancer patients. Nevertheless, the exact mechanism by which amino-BPs would be responsible for ONJ is still debatable. Recent findings suggest a possible alternative explanation for BPs role in this pattern. In the present work we discuss how a condition of osteomalacia and low vitamin D levels might be determinant factors.

Medication-Related Osteonecrosis of the Jaw Spontaneously Occurred in a Patient with Chronic Myelogenous Leukemia Only by Imatinib: A Report of a Rare Case

The prevalence of medication-related osteonecrosis of the jaw (MRONJ) associated with molecular-targeted therapies such as bevacizumab and sunitinib has been constantly increasing in recent years. MRONJ frequently occurs after invasive dental procedures such as tooth extraction in patients currently or with a previous history of receiving antiresorptive agents including bisphosphonates and/or denosumab. Here, we report a rare case of spontaneously occurring MRONJ of the mandible in a 52-year-old Japanese woman with chronic myelogenous leukemia (CML) who was administered imatinib for 9 years. She had never been treated with antiresorptive agents, and her MRONJ developed spontaneously. Although there have been few reports of MRONJ related to imatinib, our case reported here indicates that imatinib may be capable of causing spontaneous MRONJ.

Bosutinib-induced osteonecrosis of the jaw in a patient with chronic myeloid leukemia: a case report

Medication-related osteonecrosis of the jaw (MRONJ) is an uncommon adverse drug reaction that can be induced by certain therapeutic drugs, including antiresorptive and antiangiogenic agents. Here, we describe the first case of ONJ induced by bosutinib, a tyrosine kinase inhibitor, in a patient with chronic myeloid leukemia (CML) who was not taking an antiresorptive agent. A 65-year-old male with no history of either antiresorptive treatment or dental surgery but diagnosed with CML had been undergoing treatment with bosutinib for 2 years. He developed right mandibular stage 2 osteonecrosis. The patient eventually underwent extensive surgery consisting of removal of the necrotic bone and infected soft tissue in combination with nasolabial flap reconstruction. He obtained complete resolution of MRONJ at 12 months postoperatively. As new cancer therapies become available, it is important that clinicians are aware of this novel case of bosutinib-induced ONJ in a patient undergoing CML treatment.

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 of the jaw: Analysing the range of implicated drugs from the Australian database of adverse event notifications

AIMS

Medication-related osteonecrosis of the jaw (MRONJ) is an uncommon but potentially debilitating condition, characterised by nonhealing jawbone, with or without mucosal exposure, in the presence of certain drugs. Those already strongly associated with MRONJ include antiresorptives denosumab and bisphosphonates; however, a growing range of other non-antiresorptive drugs is implicated. The aim of this study was to analyse all case reports of MRONJ submitted to the publicly available Database of Adverse Event Notification from the Therapeutic Goods Administration in Australia.

METHODS

The Therapeutic Goods Administration was contacted on 6 January 2020 and asked for all reports containing the words "osteonecrosis of the jaw". This was provided in a spreadsheet of de-identified reports received from commencement of the database in 1971 until 1 October 2019.

RESULTS

The drugs implicated in the 419 cases were divided by established drugs with MRONJ and secondary drugs that possibly contribute to MRONJ development. While the majority of cases were associated with denosumab or bisphosphonates (n = 405), there were 14 reports where secondary agents that directly or indirectly affect bone turnover, were also implicated. Some of these secondary drugs, including adalimumab, etanercept, methotrexate and rituximab have previously been associated with MRONJ in published case reports.

CONCLUSIONS

This study contributes to the sparse but growing literature associating an increasing number of drugs with MRONJ, and underscores the importance of considering all possible drugs that elevate a patient's MRONJ risk.

Shotgun metagenome sequencing identification of a set of genes encoded by Actinomyces associated with medication-related osteonecrosis of the jaw

Medication-related osteonecrosis of the jaw (MRONJ) is intractable and severely affects a patient’s quality of life. Although many cases of MRONJ have been reported in the past decade, the disease pathophysiology is unclear and there are no evidence-based therapeutic strategies. MRONJ usually features bone inflammation and infection. Prior studies that explored the association between MRONJ and microbial infection used the culture-based approach, which is not applicable to hundreds of unculturable taxa in the human oral microbiome, or 16S ribosomal RNA gene sequencing, which does not provide quantitative information of the abundance of specific taxa, and information of the presence, abundance, and function of specific genes in the microbiome. Here, deep shotgun metagenome sequencing (>10 Gb per sample) of bulk DNA extracted from saliva of MRONJ patients and healthy controls was performed to overcome these limitations. Comparative quantitative analyses of taxonomic and functional composition of these deep metagenomes (initially of 5 patients and 5 healthy controls) revealed an average 10.1% increase of genus Actinomyces and a 33.2% decrease in genus Streptococcus normally predominant in the human oral microbiota. Pan-genome analysis identified genes present exclusively in the MRONJ samples. Further analysis of the reads mapping to the genes in the extended dataset comprising five additional MRONJ samples and publicly available dataset of nine healthy controls resulted in the identification of 31 genes significantly associated with MRONJ. All these genes were encoded by Actinomyces genomic regions. Of these, the top two abundant genes were almost exclusively encoded by Actinomyces among usual taxa in the human oral microbiota. The potential relationships of these key genes with the disease are discussed at molecular level based on the literature. Although the sample size was small, this study will aid future studies to verify the data and characterize these genes in vitro and in vivo to understand the disease mechanisms, develop molecular targeted drugs, and for early stage screening and prognosis prediction.