Οστεονέκρωση των γνάθων και δείκτες οστικού μεταβολισμού και αγγειογένεσης σε ασθενείς με συμπαγείς όγκους και μεταστατική οστική νόσο

Abstract

Introduction: Osteonecrosis of the jaws is a severe complication that impairs patients’ quality of life. In 2003, this complication was described for the first time and was associated with the administration of bisphosphonates. Bisphosphonates are used in the management of hypercalcemia in patients with metastatic bone disease associated with multiple myeloma and solid tumors, as well as in osteoporosis, Paget’s disease and osteogenesis imperfecta. Their mechanism of action mainly consists in the reduction of osteoclast activity but they are also thought to have antiangiogenic and antineoplasmic effects. Recently, there have been many reports in the literature for the development of osteonecrosis of the jaws in patients receiving not only bisphosphonates but also anti-angiogenic therapy such as bevacizumab and mTOR inhibitors. The complication has been described not only in patients receiving bisphosphonates in combination with anti-angiogenic therapy but also in those who were receiving antiangiogenics alone. Therefore, the complication is nowadays described as osteonecrosis of the jaws associated with medication.The pathogenic mechanism of osteonecrosis remains unclear. Many theories have been proposed but the most common were the inhibition of bone remodeling as well as the inhibition of angiogenesis. In the recent literature, inflammation has been proposed to play a key role in the pathogenesis of osteonecrosis of the jaws. Purpose: The purpose of the present study was to evaluate the changes of VEGF as a marker of angiogenesis and IL-17 as a marker of inflammation, in the serum and crevicular fluid in patients with solid tumors and bone metastases during their treatment with bisphosphonates and/or targeted therapies. Patients: Twenty-five patients were included in the study (8 males, 17 females) from 5/2011 to 10/2012. Patients were recruited from the 1st Oncology Department of ‘Metropolitan Hospital’ and were diagnosed with solid tumors amd metastases. All patients were receiving intravenous bisphosphonates alone or in combination with anti-angiogenic therapy. Methods: From the medical history of the patients were recorded: underlying diagnosis, kind of metastases, former antineoplastic treatment, administration of chemotherapy, bisphosphonates and anti-angiogenic agents and comorbidities. Oral examination was performed and basic oral care instructions were given at the initial examination. The oral and dental status of the patients was recorded and they were informed about the complication of osteonecrosis of the jaws.VEGF and IL-17 were investigated in two study points. At the first study point, serum was collected from 21 patients and crevicular fluid from 23 patients. At the second study point (6 months after the initial examination), serum was collected from 6 patients and crevicular fluid from 5 patients (8 patients passed away before the 2nd study point). All samples were stored at -800C and their analysis was performed at the laboratory of ‘Agia Sophia’ Hospital. Serum and crevicular fluid levels of VEGF and IL-17 were measured by standard quantitative ELISA kits. Statistical analysis was carried out using ANOVA and post-hoc analysis. The significance was assigned at the 3% level. Results: The mean age of the patients was 60.5 years. Underlying diagnosis were breast cancer (9/25); lung cancer (3/25); intestine cancer (3/25); other (10/25). Metastases were developed in 21/25 patients. Seventeen patients had received chemotherapy and/or hormonal therapy before the initiation of bisphosphonates and/or antiangiogenic agents and 22 patients were receiving concomitant chemotherapy and/or hormonal therapy and bisphosphonates and/or antiangiogenic agents. At the second study point, 6/7 patients were receiving concomitant chemotherapy and/or hormonal therapy during their treatment with bisphosphonates and/or antiangiogenic agents.Nine patients received i.v. zoledronic acid; 9 received bevacizumab; 5 received zoledronic acid combined with bevacizumab; one received zoledronic acid and everolimus and one received zoledronic acid, bevacizumab and temsirolimus. The mean time of bisphosphonate administration was 23.1 months. The mean time of bevacizumab administration was 13 months. VEGF srum levelsAt first study point, VEGF serum levels were similar between patients receiving bavacizumab as monotherapy and those receiving bevacizumab in combination with zoledronic acid. VEGF serum levels were significantly lower in patients who received bevacizumab only, when compared to the other medication groups. Among patients who received zoledronic acid, VEGF serum levels were lower in patients who received the drug in combination with bevacizumab than those who received zoledronic acid as monotherapy. The results were similar at the second study point. There were no significant changes between the two study points. VEGF was not detected in the crevicular fluid in both study points.IL-17 serum levelsAt the first study point, IL-17 serum levels were approximately the same in all medication groups and remained unchangeable at the second study point for each medication group. IL-17 levels in crevicular fluidUnlike VEGF, IL-17 was detected in the crevicular fluid of the patients in both study points. There were no significant differences in the levels of IL-17 in the crevicular fluid between the medication groups at the first study point. At the second study point, there were no significant changes in the levels of IL-17 in the crevicular fluid neither between the medication groups nor between the two study points.In addition, there was no correlation between the time of administration and/or the number of doses of zoledronic acid and bevacizumab and the levels of VEGF (serum levels) and IL-17 (serum levels and levels in crevicular fluid) at first study point. At the second study point, statistical analysis was not possible due to the small number of patients. All patients maintained good oral hygiene. One patient was diagnosed with jaw osteonecrosis stage I at first study point and no patient developed osteonecrosis of the jaw during the study. Discussion: In the present study, VEGF was evaluated for the first time in patients receiving bisphosphonates and/or anti-angiogenic agents. Until now, VEGF has been investigated as a possible prognostic factor for osteonecrosis of the jaw in patients receiving bisphosphonates. There are studies reporting that serum VEGF is decreased after the administration of antiresorptives (Santini et al 2007, Vincenzi et al 2012). On the contrary, Tas et al reported that there was no such decrease of serum VEGF, in agreement to our results. These results may be justified if we consider that osteonecrosis of the jaw is a local complication and maybe the levels of serum VEGF are not indicative. That is why we tried to evaluate the levels of VEGF in the crevicular fluid but unfortunately, the agent was not detected in any study point. As far as IL-17 is conserned, the role of this cytokine in inflammation and periodontitis is well-known. IL-17 seems to be increased in the serum and crevicular fluid of patients with periodontitis when compared to healthy patients. Increased levels of IL-17 may result in bone loss through the upregulation of RANKL (Cheng et al 2014). Zhang et al reported that the serum levels of IL-17 were increased in patients with established osteonecrosis (Zhang et al 2013) while Oteri et al reported a decrease in the serum levels of the cytokine in patients with osteonecrosis (Oteri el 2008). In the present study, there were no significant changes in the levels of IL-17 neither in the serum nor in the crevicular fluid between the patient groups and the two study points as well. These results may be attributed to the maintenance of good oral hygiene of the patients and as a result in the absence of inflammation. In addition, no patient developed osteonecrosis of the jaws during the study. It should be referred that all patients received oral care instructions. The importance of oral hygiene in the reduction of prevalence of osteonecrosis of the jaws has already been reported in the literature (Rosella et al 2016, Nicolatou-Galitis et al 2011). Conclusions: The lower VEGF serum levels in patients who received bevacizumab indicate that bevacizumab is the main anti-angiogenic factor and that zoledronic acid acquires lower anti-angiogenic properties. The absence of significant differences in the levels of IL-17 in the serum and in the crevicular fluid may be justified since all patients had a good oral status and there were no signs of inflammation. It seems that the visit of an appropriate educated dentist (that all patients in the study had) and the education of patients on oral hygiene results in the prevention of jaw osteonecrosis.

Εισαγωγή: Η επιπλοκή της οστεονέκρωσης των γνάθων έχει συσχετιστεί με διάφορα φάρμακα. Ανάμεσα στα φάρμακα αυτά συγκαταλέγονται τα διφωσφονικά άλατα και οι αναστολείς αγγειογένεσης όπως το bevacizumab και οι αναστολείς mTOR, τα οποία διαθέτουν αντι-αγγειογενετικές ιδιότητες μέσω διαφορετικών κυτταρικών στόχων. Αν και από το 2009 έχει αναφερθεί μια πληθώρα περιστατικών οστεονέκρωσης των γνάθων στη βιβλιογραφία και έχει περιγραφεί η κλινική και ακτινογραφική της εικόνα, ο παθογενετικός μηχανισμός της επιπλοκής παραμένει άγνωστος. Σκοπός: Ο σκοπός της παρούσας εργασίας ήταν να αξιολογηθούν οι αλλαγές στις τιμές δύο δεικτών αγγειογένεσης: του παράγοντα VEGF και της IL-17 τόσο στον ορό του αίματος όσο και στο ουλικό υγρό ασθενών με συμπαγείς όγκους και οστική νόσο κατά τη διάρκεια της θεραπείας τους με διφωσφονικά άλατα ή/και στοχεύουσες θεραπείες. Ασθενείς: Στη μελέτη συμπεριελήφθησαν 25 ασθενείς (8 άνδρες, 17 γυναίκες) με μέσο όρο ηλικίας τα 60,5 έτη. Η υποκείμενη νόσος ήταν καρκίνος μαστού σε 9 εννέα ασθενείς, καρκίνος πνεύμονος σε 3 ασθενείς, καρκίνος εντέρου σε 3 ασθενείς και διάφοροι άλλοι συμπαγείς όγκοι στους υπόλοιπους 10 ασθενείς. Όσον αφορά στη λαμβανόμενη θεραπεία, εννέα ασθενείς ελάμβαναν ενδοφλέβια ζολενδρονικό οξύ, εννεά ασθενείς ελάμβαναν bevacizumab, πέντε ασθενείς ελάμβαναν ζολενδρονικό οξύ σε συνδυασμό με bevacizumab, ένας ασθενής ελάμβανε ζολενδρονικό οξύ σε συνδυασμό με everolimus και ένας ασθενής ελάμβανε ζολενδρονικό οξύ σε συνδυασμό με bevacizumab και temsirolimus. Ο μέσος χρόνος χορήγησης των διφωσφονικών αλάτων ήταν 23,1 μήνες και ο μέσος χρόνος χορήγησης του bevacizumab ήταν 13 μήνες. Μέθοδος: Κατά την αρχική εξέταση πραγματοποιήθηκε λεπτομερής καταγραφή του ιατρικού ιστορικού των ασθενών. Πραγματοποιήθηκε, επίσης, οδοντιατρική και στοματολογική εξέταση των ασθενών, ενώ δόθηκαν οδηγίες στοματικής υγιεινής. Οι δείκτες VEGF και IL-17 διερευνήθηκαν σε δύο φάσεις. Η πρώτη φάση ήταν κατά την αρχική εξέταση. Σε αυτή τη χρονική στιγμή, έγινε συλλογή ορού αίματος από 21 ασθενείς και ουλικού υγρού από 23 ασθενείς. Η δεύτερη φάση συλλογής δειγμάτων ήταν κατά την επανεξέταση των ασθενών, η οποία πραγματοποιήθηκε 6 μήνες μετά την αρχική εξέταση. Κατά τη χρονική αυτή στιγμή, πραγματοποιήθηκε συλλογή ορού αίματος από 6 ασθενείς και ουλικού υγρού από 5 ασθενείς (8 ασθενείς απεβίωσαν πριν την επανεξέταση). Όλα τα δείγματα αποθηκεύτηκαν στους -80C. Η ανάλυση των δειγμάτων πραγματοποιήθηκε στο εργαστήριο Βιοχημείας του Νοσοκομείου «Παίδων-Αγία Σοφία». Τα επίπεδα των VEGF και IL-17 στον ορό του αίματος και το ουλικό υγρό μετρήθηκαν με τη μέθοδο ELISA.Αποτελέσματα: Για τη σύγκριση των επιπέδων τόσο του παράγοντα VEGF όσο και της IL-17 στον ορό του αίματος και στο ουλικό υγρό, οι ασθενείς χωρίστηκαν σε ομάδες ανάλογα με τη θεραπεία που ακολουθούσαν. Όσον αφορά στον παράγοντα VEGF, τα επίπεδά του στον ορό του αίματος ήταν χαμηλότερα στους ασθενείς που ελάμβαναν bevacizumab ως μονοθεραπεία σε σύγκριση με τις υπόλοιπες ομάδες τόσο κατά την αρχική εξέταση όσο και στην επανεξέταση. Μεταξύ των ασθενών που έλαβαν ζολενδρονικό οξύ, τα επίπεδα του VEGF στον ορό του αίματος ήταν χαμηλότερα στους ασθενείς που έλαβαν συνδυασμό με bevacizumab σε σχέση με εκείνους που έλαβαν ζολενδρονικό οξύ ως μονοθεραπεία και στις δύο φάσεις συλλογής δειγμάτων. Ο παράγοντας VEGF δεν ανιχνεύθηκε στο ουλικό υγρό. Όσον αφορά στην IL-17, τα επίπεδά της στον ορό του αίματος ήταν σχετικά ίδια σε όλες τις ομάδες ασθενών κατά την αρχική εξέταση και παρέμειναν σταθερά κατά την επανεξέταση για κάθε ομάδα ασθενών. Κατά την αρχική εξέταση, δεν υπήρχαν σημαντικές διαφορές στα επίπεδα της IL-17 στο ουλικό υγρό μεταξύ των ομάδων των ασθενών. Κατά την επανεξέταση, δεν παρατηρήθηκαν αλλαγές στα επίπεδα της IL-17 στο ουλικό υγρό ούτε μεταξύ των ομάδων των ασθενών ούτε σε σχέση με την αρχική εξέταση. Όλοι οι ασθενείς είχαν πολύ καλή στοματική υγιεινή και μόνο μία ασθενής διαγνώστηκε με οστεονέκρωση της γνάθου. Συμπεράσματα: Τα χαμηλά επίπεδα του παράγοντα VEGF στον ορό του αίματος σε ασθενείς που ελάμβαναν bevacizumab υποδεικνύουν πως το φάρμακο αυτό είναι ο κύριος αντι-αγγειογενετικός παράγοντας και ότι το ζολενδρονικό οξύ διαθέτει μικρή αντι-αγγειογενετική ικανότητα. Η απουσία σημαντικών διαφορών στα επίπεδα της IL-17 τόσο στον ορό του αίματος όσο και στο ουλικό υγρό των ασθενών μπορεί να διακιολογηθεί λόγω της καλής στοματικής υγείας των ασθενών και της απουσίας φλεγμονής. Φαίνεται πως η αξιολόγηση των ασθενών από κατάλληλα εκπαιδευμένο οδοντίατρο και η εκπαίδευσή τους στην άσκηση στοματικής υγιεινής μπορεί να οδηγήσει στην πρόληψη της οστεονέκρωσης των γνάθων.