Evaluation of serum c-terminal telopeptide (CTX) value for the risk of medication related osteonecrosis of the jaws

Abstract

AimThe aim of this study was to evaluate pre- and post-treatment serum CTX levels of patients treated with bisphosphonate (BP) and the correlation of levels with MRONJ risk.MethodsPatients treated with BP by the Endocrinology and Oncology Departments were included in this study. Blood samples were taken before and 12 months after BP treatment, and serum CTX values were determined with clinical examinations.ResultsA total of 72 patients were included in the study. Of these patients, 32 had oncological and 40 had endocrinological disorders. The mean CTX value of all the patients was 453.7 (245.7-734.3) pg/ml, in oncology patients, it was 705.9 (398.6-945.6) pg/ml and in endocrine patients, it was 360.4 (209.2-598.2) pg/ml (p<0.001). The mean post-treatment CTX value of the remaining patients was 164.1 (106.9-301.8) pg/ml, and the difference was statistically significant before and after BP treatment (p<0.001). Among the patients included in the study, MRONJ was only observed in one oncology patient 18 months after the initial BP treatment.ConclusionMRONJ can be prevented by performing all dental treatments before BP treatment and eliminating local risk factors. CTX values should not only be evaluated after BP treatment, but also it may be useful to check before BP treatment to determine the course of the treatment.

Keywords

Introduction

Bisphosphonates (BP) are antiresorptive agents that are frequently used in metabolic bone diseases, bone metastases of solid tumors, and in the control of skeletal complications of multiple myeloma.¹ BPs are used orally or intravenously and are divided into two main groups with and without amino groups.² Nitrogen-containing BPs (pamidronate, alendronate, risedronate, ibandronate, zoledronate) have a higher potential for side effects than BPs without nitrogen (etidronate).³ Although both groups show their effects through different enzymes in the intracellular cycle, their activities on bone metabolism are mainly through the inhibition of osteoclast functions.⁴
Medication related osteonecrosis of the jaws (MRONJ) is a side effect of BP treatment and characterized by exposed bone localized in the maxilla or mandible for more than 8 weeks in a patient actively or previously using antiresorptive without any history of radiation.⁵ MRONJ was first reported in 2003. Since then, it has become a common complication, seen in many published studies.^6-7 Not only BP treatment is responsible for MRONJ, but also denosumab and other antiresorptive agents are found to be associated with MRONJ. Therefore, the term antiresorptive agent-related osteonecrosis of the jaws (ARONJ) also has been used in the literature.⁸
Most of the patients using BPs are exposed to intense hospital visits and these patients mostly consist of individuals with low daily vital activity levels. For this reason, methods which could reduce hospital visits and be applied easily in all centers were investigated. Studies in recent years have focused on bone formation and destruction biomarkers in the blood. In addition, the number of genetic research studies has increased. Bone destruction markers may be useful in determining the bone resorption rate in these patients. Cross-linked carboxy terminal telopeptide (CTX) of type 1 collagen is one of the most commonly used markers. Marx et al. firstly described the CTX as a marker for MRONJ risk in 2008, and a value of less than 100 pg/ml was found to be related to a high risk of MRONJ.⁹
A literature survey was performed and it was concluded that CTX levels of patients under BP treatment were measured before dentoalveolar surgery for the determination of the risk of MRONJ or after the development of MRONJ. However, preoperative CTX levels were unknown in these MRONJ patients. For this reason, the study aimed to evaluate the significance of pre- and post-treatment CTX values in terms of MRONJ risk in patients who will be started on BP therapy, and to use it as a prognostic marker for early diagnosis.

Materials and Methods

This study was carried out with the approval of the Local Ethics Committee of Erciyes University and followed the Declaration of Helsinki on Medical Protocol and Ethics. Erciyes University Scientific Research Projects Unit supported the study (TSA-2015-5965), and carried it out at the Dentistry Faculty, Department of Oral and Maxillofacial Surgery, in cooperation with the Hematology and Endocrinology Departments at the Faculty of Medicine. Patients who started BP therapy for metabolic bone disorders (endocrinology patients) and to prevent bone metastasis (oncology patients) were included and detailed consent was given by all volunteers. Patients who did not want to participate voluntarily in the study, refused drug treatment and stated they would not attend the control visits were excluded from the study. A power analysis indicated the adequacy of 72 patients in the study.Preoperative ProceduresIn the first step of the study, to determine the preoperative CTX value of the included patients, approximately 10 ml of blood samples were drawn into the biochemistry tube and the serum was separated by centrifugation at 4000 rpm for 15 minutes in the morning while fasting and the separated serum was stored in a -80°C. In addition, the clinical and radiological dental examinations of the participants were performed by the same maxillofacial surgeon, and all dental treatments were completed before BP therapy. Patients were referred to the relevant departments to start BP treatment and were recalled for follow-up visits 12 months later.Postoperative ProceduresDetailed clinical and radiological examinations of the maxillofacial region were performed for possible osteonecrosis and MRONJ risk in the patients six months after BP treatment. Dental treatments were completed in consultation with the relevant departments, if necessary. Blood samples were taken to determine the postoperative serum CTX levels of the patients 12 months after initial BP treatment. All patients were informed about MRONJ and were recalled every 6 months for a determination of the earliest possible symptoms of MRONJ and routine dental examination.ELISA AssayPreoperative and postoperative blood samples were analyzed with the Enzyme-Linked Immunosorbent Assay (ELISA) with the use of specific kits (Elecsys β-Crosslaps®, Roche Diagnostics, Manheim, Germany) for the determination of preoperative and postoperative serum CTX levels. Enzyme-labeled antibody was inserted into the antibody-coated sample and standard wells. Substrate solution was added to each well and incubated. After incubation, color change occurred in the presence of CTX. The concentration of CTX in the blood samples was determined by comparing the O.D. to the standard curve.Ethical ApprovalThis study was approved by the Ethics Committee of Erciyes University Scientific Research Projects (Date: 06.02.2015, Decision No: TSA-2015-5965).Statistical AnalysisData normality was assessed with the Shapiro-Wilk test and histogram, q-q graphs. The homogeneity of the variance was examined using the Levene test. Independent two samples, the Mann-Whitney U, dependent two samples, and Wilcoxon tests were used for the comparisons. Data were indicated as mean ± standard deviation, median (1st-3rd quartiles), or frequencies (percentages). TURCOSA (Turcosa Analytics Ltd. Co., Turkey, www.turcosa.com.tr) was used for the analysis, and p=0.05 was considered statistically significant.

Results

The study included 72 patients. 23.6% of all patients were men (n = 17) and 76.4% (n = 55) were women. Forty patients in Group 1 (55.5%) were referred by the Endocrinology Department, and 32 patients (44.5%) in Group 2 were referred by the Oncology Department. Osteoporosis is the main reason for BP treatment in endocrine patients and BP treatment was performed in Group 2 patients to prevent bone metastasis of solid tumors. According to the group of the patients, 90% (n = 36) of patients in Group 1 consisted of women, and 47% (n = 15) of the patients in Group 2 were women, and the difference was significant (p<0.001). The mean age of all patients was 61.3 ± 9.8 years (min = 34, max = 84). The mean age in Group 1 was 61.4 ± 9.6 and 61.1 ± 10.4 in Group 2 (p=0.83).
When the pre-treatment CTX values of the patients were measured, the mean CTX value of all patients was 453.7 (245.7-734.3) pg/ml. According to the groups, pre-treatment CTX value was 360.4 (209.2-598.2) pg/ml in Group 1 and 705.9 (398.6-945.6) pg/ml in Group 2, with significant difference (p<0.001).
In the second step of the study, 38 patients were excluded from the study. In the endocrinology group, 19 patients were excluded due to discontinuation of the drug treatment (n = 9), not coming to the follow-ups (n = 5), and withdrawal from the study (n = 5). In the oncology group, 19 were excluded because of a short survey of the diseases leading to death in stage 4 cancers. Post-treatment CTX values of the remaining 34 patients were measured after 12 months of initial BP treatment. Twenty-one (62%) patients were in the endocrine group and 13 (38%) were oncology patients. The post-treatment serum CTX value of all patients was 164.1 (106.9-301.8) pg/ml. According to the groups, the post-treatment mean CTX was 231 ± 131.9 pg/ml in Group 1 and 140.1 (100-187.6) pg/ml in Group 2, with no difference (p=0.19).
The mean pre-treatment CTX value of the 34 patients, whose second blood samples were obtained, was 413.3 (234.2-641.6) pg/ml, and the postoperative CTX value was 164.1 (106.9-301.8) pg/ml, and the difference was significant (p<0.001) (Table 1).
The systemic conditions of the remaining 34 patients were also evaluated. In these patients, 5 patients have used 70 mg alendronate once a week; 9 patients have used 35 mg risedronate once a week, and 7 patients have used 150 mg ibandronate once a month orally. Five patients used 6 mg ibandronate once a month and 8 patients used 4 mg zoledronate once a month intravenously. The mean treatment time was 12 months in Group 1 (min: 2 - max: 36). All patients in Group 2 had been treated with BPs for 12 months except for 2 patients whose treatment times were 24 months (Table 2).
BP treatment was applied for breast (n = 5), colon (n = 2), prostate (n = 2), lung (n = 2), gastric (n = 1) and renal cancers (n = 1) in Group 2. A total of 18 patients had other systemic conditions such as diabetes mellitus (n = 7), hypertension (n = 9), thyroid diseases (n = 3), and cardiac arrhythmia (n = 2). Only one osteoporotic patient had been using steroid treatment (40 mg Fluocortolone once a day for 2 years) in addition to IV BP therapy in Group 1.
MRONJ was observed in only a male patient, who had intravenous BP treatment (6 mg ibandronate for 12 months) because of a gastrointestinal stromal tumor and colon cancer 18 months after the initial BP treatment. In addition, the patient used 50 mg of sunitinib daily as an antineoplastic agent. Considering the CTX values of the patient, the preoperative CTX value was 428 pg/ml and the postoperative CTX value was 109 pg/ml. Although no dental treatment, such as tooth extraction or periodontal surgery, was performed, MRONJ development was thought to be caused by irritation of the dentures during sunitinib therapy. In the clinical and radiological examination, stage 2 MRONJ was diagnosed according to the AAOMS (American Association of Oral and Maxillofacial Surgeons) criteria and the treatment of MRONJ was performed according to the relevant guideline.⁵ A consultation was performed with the oncology department for a drug holiday and no additional BP treatment was required for the patient who had previously completed BP treatment and sunitinib therapy was continued. After the antimicrobial therapy, the necrotic bone was surgically debrided and complete wound healing was observed 3 months later (Figure 3). The patient was checked for 12 months and no additional MRONJ occurred during sunitinib usage.

Discussion

MRONJ is an uncontrollable consequence in osteoporosis and metastatic cancer patients who are treated with antiresorptive medicines, such as BPs, denosumab, a human IgG2 monoclonal antibody against the receptor activator of nuclear factor-kappa B ligand (RANKL). In cancer patients receiving BP, antiangiogenic drugs, denosumab, and molecularly targeted medicines such as tyrosine kinase inhibitors are also linked to MRONJ or enhance the risk of MRONJ.¹⁰ The incidence of MRONJ is greater in oncological patients because of higher BP doses than in those with osteoporosis.¹¹ MRONJ is a difficult and complex clinical condition to treat. Although appropriate treatment protocols are applied according to the clinical staging system, surgical interventions fail due to impairment in wound healing. Therefore, the prevention of MRONJ and early diagnosis are very important in the clinical aspect.
CTX, which is a bone-specific marker, is a breakdown product of type 1 collagen, and serum CTX levels increase in patients with osteoporosis and metastatic bone tumors while it tends to decrease during antiresorptive therapy.¹² Marx et al. have suggested the use of CTX estimation as an indicator of the risk of MRONJ. A value of less than 100 pg/ml was represented as a high risk, 100-150 pg/ml, a moderate, and greater than 150 pg/ml, minimal or no risk.⁹ However, in different studies, serum CTX values are reported as not a significant predictor of MRONJ risk.^13-14-15
Determination of serum CTX level is useful in evaluating the effectiveness of osteoporosis treatment and skeletal complications. Studies have shown that high concentrations of serum CTX reduce the survival rate of cancer patients.¹⁶ However, it is also argued that CTX will be higher in cancer patients due to high collagen destruction and is not a significant determinant.¹⁶ In the present study, the serum CTX concentration in oncology patients was higher than in osteoporotic patients before BP treatment, and the CTX values decreased rapidly in a short time. Therefore, it is recommended to check CTX values in oncology patients at short intervals.
Comorbid conditions in oncology patients are related to a greater risk of MRONJ such as diabetes.⁵ Although 7 patients had diabetes mellitus as a comorbid condition in the present study, MRONJ did not develop in any of them. Also, there was one patient in Group 2 who received steroids additionally to IV BP treatment, MRONJ did not occur in this patient.
Furthermore, local factors also have a great impact on MRONJ development as well as systemic conditions. Dentoalveolar surgical procedures, such as tooth extraction, periapical and periodontal surgical procedures, dental implant placement, regional anatomical differences, and accompanying oral problems can be classified as local risk factors.¹⁷ The risk of MRONJ in patients using oral BPs after dental extraction is 0.5% and ranges from 1.6-14.8% in IV users.⁵ Therefore, such interventions should be avoided in patients using BPs and all dental treatments should be completed before BP treatment.
In this study, although all dental procedures were completed before BP treatment in all patients, MRONJ developed in a patient because of denture irritation. The non-healing mucosal defect caused by dentures is known as a way for oral flora to access the bone. The patient had been using sunitinib daily as an antineoplastic agent after BP treatment and MRONJ occurrence was thought to be associated with sunitinib usage. However, serum CTX values of 15 patients after BP treatment were lower than 150 pg/ml and MRONJ did not develop in any other patients during the follow-up visits for 2 years. Therefore, CTX is not an exact definitive marker, and it may be more favorable to evaluate changes in the pre- and post-treatment CTX levels, rather than only evaluating CTX levels during active BP treatment for MRONJ risk assessment.
There are some limitations of this study. Although the study started with 72 patients, most of the patients left the study for various reasons and the study was completed with 34 volunteers. In addition, although oncology patients were treated with IV BP, all the endocrine patients included in the study were started on oral BP treatment. It was reported that the MRONJ occurrence rate in osteoporotic patients receiving long-term oral BP was 0.1%, which increased to 0.21% when used for more than 4 years.⁵ Considering that the possibility of MRONJ occurrence in patients using oral BP increased after 4 years, it was concluded that the 12-month period determined for this study was insufficient to determine MRONJ risk in endocrine patients. For this reason, clinical studies with more patients who have the same type of BP treatment are needed to obtain better results.
In conclusion, CTX values are not only evaluated after BP treatment, but also may be checked before BP treatment to determine the course of the treatment. MRONJ can be prevented by performing all dental treatments before BP treatment and eliminating local risk factors. Thus, clinicians should consult with oral surgeons before BP treatment even if the patient has no dental complaints.

References

1. Govaerts D, Piccart F, Ockerman A, et al. Adjuvant therapies for MRONJ: a systematic review. Bone. 2020;141:115676. doi:10.1016/j.bone.2020.115676
   Article · PubMed · Google Scholar
2. Vermeer JA, Jansen ID, Marthi M, et al. Jaw bone marrow-derived osteoclast precursors internalize more bisphosphonate than long-bone marrow precursors. Bone. 2013;57(1):242-251. doi:10.1016/j.bone.2013.08.007
   Article · PubMed · Google Scholar
3. O’Connell JE, Ikeagwani O, Kearns GJ. A role for C-terminal cross-linking telopeptide (CTX) level to predict the development of bisphosphonate-related osteonecrosis of the jaws (BRONJ) following oral surgery? Ir J Med Sci. 2012;181(2):237-242. doi:10.1007/s11845-011-0790-5
   Article · PubMed · Google Scholar
4. Endo Y, Funayama H, Yamaguchi K, et al. Basic studies on the mechanism, prevention, and treatment of osteonecrosis of the jaw induced by bisphosphonates. Yakugaku Zasshi. 2020;140(1):63-79. doi:10.1248/yakushi.19-00125
   Article · PubMed · Google Scholar
5. Ruggiero SL, Dodson TB, Aghaloo T, Carlson ER, Ward BB, Kademani D. American Association of Oral and Maxillofacial Surgeons’ position paper on medication-related osteonecrosis of the jaws—2022 update. J Oral Maxillofac Surg. 2022;80(5):920-943. doi:10.1016/j.joms.2022.02.008
   Article · PubMed · Google Scholar
6. Kim J, Lee DH, Dziak R, Ciancio S. Bisphosphonate-related osteonecrosis of the jaw: current clinical significance and treatment strategy review. Am J Dent. 2020;33(3):115-128.
   PubMed · Google Scholar
7. Chien HI, Chen LW, Liu WC, et al. Bisphosphonate-related osteonecrosis of the jaw. Ann Plast Surg. 2021;86(2S suppl 1):S78-S83. doi:10.1097/sap.0000000000002650
   Article · PubMed · Google Scholar
8. Yoneda T, Hagino H, Sugimoto T, et al. Antiresorptive agent-related osteonecrosis of the jaw: position paper 2017 of the Japanese Allied Committee on Osteonecrosis of the Jaw. J Bone Miner Metab. 2017;35(1):6-19. doi:10.1007/s00774-016-0810-7
   Article · PubMed · Google Scholar
9. Marx RE, Cillo JE Jr, Ulloa JJ. Oral bisphosphonate-induced osteonecrosis: risk factors, prediction of risk using serum CTX testing, prevention, and treatment. J Oral Maxillofac Surg. 2007;65(12):2397-2410. doi:10.1016/j.joms.2007.08.003
   Article · PubMed · Google Scholar
10. Awad ME, Sun C, Jernigan J, Elsalanty M. Serum C-terminal cross-linking telopeptide level as a predictive biomarker of osteonecrosis after dentoalveolar surgery in patients receiving bisphosphonate therapy: systematic review and meta-analysis. J Am Dent Assoc. 2019;150(8):664-675. doi:10.1016/j.adaj.2019.03.006
    Article · PubMed · Google Scholar
11. Lorusso L, Pieruzzi L, Gabriele M, et al. Osteonecrosis of the jaw: a rare but possible side effect in thyroid cancer patients treated with tyrosine-kinase inhibitors and bisphosphonates. J Endocrinol Invest. 2021;44(12):2557-2566. doi:10.1007/s40618-021-01634-0
    Article · PubMed · Google Scholar
12. Salgueiro M, Stribos M, Zhang LF, Stevens MR, Awad ME, Elsalanty M. Value of pre-operative CTX serum levels in the prediction of medication-related osteonecrosis of the jaw (MRONJ): a retrospective clinical study. EPMA J. 2019;10(1):21-29. doi:10.1007/s13167-019-0160-3
    Article · PubMed · Google Scholar
13. Traboulsi-Garet B, Jorba-García A, Camps-Font O, Alves FA, Figueiredo R, Valmaseda-Castellón E. Is serum C-terminal telopeptide cross-link of type 1 collagen a reliable parameter for predicting the risk of medication-related osteonecrosis of the jaws? A systematic review and meta-analysis of diagnostic test accuracy. Clin Oral Investig. 2022;26(3):2371-2382. doi:10.1007/s00784-022-04383-3
    Article · PubMed · Google Scholar
14. Peisker A, Raschke GF, Fahmy MD, et al. Cross-sectional study of four serological bone turnover markers for the risk assessment of medication-related osteonecrosis of the jaw. J Craniofac Surg. 2018;29(2):e137-e140. doi:10.1097/scs.0000000000004224
    Article · PubMed · Google Scholar
15. Enciso R, Keaton J, Saleh N, Ahmadieh A, Clark GT, Sedghizadeh PP. Assessing the utility of serum C-telopeptide cross-link of type 1 collagen as a predictor of bisphosphonate-related osteonecrosis of the jaw: a systematic review and meta-analysis. J Am Dent Assoc. 2016;147(7):551-560. doi:10.1016/j.adaj.2016.02.011
    Article · PubMed · Google Scholar
16. Aufderklamm S, Hennenlotter J, Rausch S, et al. Oncological validation of bone turnover markers C-terminal telopeptide of type I collagen (1CTP) and peptides N-terminal propeptide of type I procollagen (P1NP) in patients with prostate cancer and bone metastases. Transl Androl Urol. 2021;10(10):4000-4008. doi:10.21037/tau-20-1120
    Article · PubMed · Google Scholar
17. Ferreira LH Jr, Mendonça KD Jr, Chaves de Souza J, et al. Bisphosphonate-associated osteonecrosis of the jaw. Minerva Dent Oral Sci. 2021;70(1):49-57.
    PubMed · Google Scholar

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