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Journal of Disability and Oral Health (2010) 11/1 03/09 Osteoradionecrosis - a review of prevention and management M Burke BDS FDS RCS(Eng)1 and M Fenlon MA PhD BDentSc MGDS FDS RCS(Ed)2 Guy’s and St Thomas’ NHS Foundation Trust, 2King’s College London 1 Abstract It has long been recognised that patients who receive radiotherapy for cancer of the head and neck area are at risk of developing osteoradionecrosis (ORN) of the jaws. Guidelines to reduce risk have been written, based upon the evidence of many studies which have looked at the incidence of ORN in different groups. Much of the research was carried out over 20 years ago and more recent analysis of data and consideration of the changes in radiotherapy raises the question as to whether modifications to the guidance is now needed. There is a wide variation in recommendations and a simpler, more unified approach to prevention of ORN could be developed as well as research on recent management techniques. Clinical relevance: ORN is a serious condition which can adversely affect quality of life and treatment outcome of patients who have already suffered the trauma of oral cancer. Features include chronic exposed bone which fails to heal, pain, fractures and fistulae. The incidence is decreasing, probably as a result of improved radiotherapy techniques. The general dental practitioner may play the greatest role in prevention with regular oral health care. Key words: Radiotherapy, osteoradionecrosis Introduction First described by Regaud in Paris in 1920, osteoradionecrosis is non-healing exposed bone in an area previously irradiated. Although defined as exposed bone present for over three months, realistically, exposed bone of just a few weeks duration gives an early sign (Kanatas et al., 2002). In the jaws it can occur in dentate and edentulous patients, spontaneously or following trauma, for example, after tooth extraction (Figures 1 and 2). It may be symptomless or the patient may complain of sharp bony edges or of pain. Sometimes the area of exposed necrotic bone enlarges and considerable areas are exposed, there may be surrounding redness or a discharging sinus either intra- or extra-orally and development of a pathological fracture. When severe it can be very debilitating and require surgical resection. Figure 1 Osteoradionecrosis following dental extraction before radiotherapy on the lower left (a) and after radiotherapy on the right (b) 04 Journal of Disability and Oral Health (2010) 11/1 Figure 2 Radiological appearance of patient in Figure 1 Figure 3 Bone resection and grafting for management of osteoradionecrosis after failure of conservative treatment, same patient as in Figure 1 Incidence Studies in the literature of varying population groups report the incidence of ORN to range from 0.95 to 35% (Reuther et al., 2003). The wide range may be a result of differences in the study populations or length of observation. Clayman (1997) reviewed the incidence of ORN reported in the literature for all patients who had received radiotherapy, whether they had extractions or not, dividing it pre- and post-1968, by which time most units had megavoltage machines. The incidence was 11.8% and 5.4% respectively. Reviewing literature post-1968, of patients only undergoing extractions, the rate was 5.8% for extractions post radiotherapy, and there was little difference between this and rate for extractions pre radiotherapy (4.4%) . Wahl (2006), reviewed cases since 1986 and found 3.0-3.2% and 3.1-3.5% incidence of ORN when extractions were undertaken, pre- and post-radiotherapy, respectively. Since 1997, the incidence was even lower, 3.0% for all cases, not limited to patients who had extractions (Whal, 2006). Risk Factors The risk of ORN is related to the dose of radiation, the higher the dose, the greater the risk; below 50 Gray it is uncommon, above 60 Gray it is more frequent (Curi and Lauria, 1997). In a study by Thorn et al. (2000) 93% of patients with ORN had doses in excess of 64 Gray. Combined chemotherapy and radiotherapy led to earlier development of ORN than radiotherapy alone (Reuther et al., 2003). Careful planning of fields using IMRT may reduce risk of ORN even when in combination with chemotherapy (Huang et al., 2008). Other factors implicated include high Body Mass Index and use of steroids in patients receiving more than 66Gy (Goldwaser et al., 2007). Osteoradionecrosis is more likely to develop in the mandibular molar area when this is in the field of radiation, believed to be a result of less blood supply in the mandible (Curi and Lauria, 1997). The greatest risk factor is considered to be dental extractions, either pre- or post-radiation (Thorn et al., 2000) and a recent review suggests little difference between these (Whal, 2006). A retrospective study over 30 years by Reuther et al, (2003) found tooth extractions were responsible for 50% of cases. Careful, atraumatic extraction technique is important in reducing the risk (Maxymiw et al., 1991). Other factors are denture trauma, in particular ORN may develop over the mylohyoid ridge, implant placement, biopsy and periodontal surgery. Osteoradionecrosis is more common with increasing age of the patient and in men (Reuther et al., 2003; Lye et al., 2007). Some studies have shown increase with use of alcohol and tobacco (Glanzmann and Gratz, 1995; Reuther et al., 2003) but others have not found this to be a risk factor (Thorn et al., 2000). Katsura et al., (2008) did not find pre treatment oral health to be a predictor of ORN but oral health one year after the end of treatment, periodontal status, radiographic evidence of advanced bone loss and pocketing greater than 5mm, were predictors of ORN. Other studies have also shown poor dental status is a risk factor (Niewald et al., 1996). The risk of ORN remains years after radiotherapy (Epstein et al., 1997) and probably for ever (Lambert et al., 1997). Some studies have found the risk decreases with time (Brown et al., 1998) although others believe it may increase (Chavez and Adkinson, 2001). There are approximately 5,000 new cases of cancer of the mouth and oropharynx in the UK each year, the number increasing especially in younger people. Approximately 90% are squamous cell carcinomas. Worldwide, it is estimated about 400,000 new cases of oral cancer are diagnosed each year and account for 3% of all cancers, but this proportion is considerably higher in the Indian sub-continent, parts of France and in Hungary (International Agency for Research on Cancer, 2003). Surgery and radiotherapy are equally effective for treatment of early stage disease (Worrell, 2005). In late stage disease, surgery followed by radiotherapy gives best survival times (Roberson et al., 1998). Radiotherapy is also given to the neck if nodal resection shows two or more lymph nodes are affected or extracapsular spread has occurred (Franceshi et al., 1993). In situations where surgery Burke and Fenlon: Osteoradionecrosis 05 is not possible or would be very debilitating, radiotherapy is given, often combined with chemotherapy which has been shown to reduce local recurrence (Munro, 1995). Radiotherapy with curative intent is used either alone or as a component of treatment in about 60% of patients with cancer of the head and neck area. A short course of radiotherapy is sometimes used in palliative care for symptom control. Radiotherapy is usually given as an external beam to the tumour site and affected tissues. Interstitial brachytherapy (placement of radioactive needles within the tumour) may be used in small tumours on the lateral border of the tongue (Henk, 1992). There have been considerable advances in radiotherapy (Harari, 2005). Since 1968 megavoltage machines have been used which can give a high dose to deep seated tumours, as occur in the oropharynx, with less skin damage. Over the last 20 years three-dimensional conformal radiotherapy has been developed: CT simulators are used in planning to determine the tumour volume and shape. The beam is shaped to this by a multi-leafed collimator to give improved accuracy. The dose is usually 50-70 Gray given in fractions of five daily doses each week over 4-6 weeks (Robinson, 2008). A more recent development of conformal planning is intensity modulated radiotherapy (IMRT), in which a varying radiation dose can be delivered to different parts at the same time. This allows increased dose to the tumour and less to surrounding structures, for example the salivary glands. Oral health related quality of life was preserved in patients in a study utilising IMRT (Parliament et al., 2004). There is also evidence that increasing the dose and shortening the treatment time can improve tumour control (Horiot et al., 1990). This is called hyperfractionation. In continuous hyperfractionated accelerated radiotherapy (CHART) treatment is given three times a day for just 12 days. The Calman Report emphasised that care should concentrate on quality of life as well as longevity (Calman and Hine, 1994). Appropriate assessment, preventive regimes and oral care before and after cancer treatment can minimise complications and improve quality of life (Sulaiman et al., 2003). Patients should be informed about the importance of oral care, with written information about the side effects of treatment (Shaw et al., 1999). Pathology of osteoradionecrosis When first described, ORN was believed to be the result of radiation delivered above a critical dose, local trauma and infection. Marx (1983) proposed a hypothesis of radiationinduced hypoxic, hypovascular and hypocellular bone, so there was inadequate repair of bone. If the overlying soft tissue was damaged, the bone became exposed and infected. In addition, radiotherapy reduces the proliferation of bone marrow, periosteal and endothelium cells and collagen production (Store and Boyson, 2000). Suppression of bone turnover has been proposed as the primary aetiological factor (Al-Nawas et al., 2004). Others have proposed that ORN is caused by a fibro-necrotic process, which is relevant to new drug treatments (Delanian et al., 2005). There is a broad spectrum of micro-organisms in osteonecrotic bone, but it is not believed to be an infectious process and microorganisms are probably opportunistic (Kanatas et al., 2002; Store et al., 2005). Prevention Dental assessment A multi-disciplinary approach to care is recommended and every patient should have a dental assessment prior to radiotherapy for the best outcome following cancer treatment (Shaw et al., 1999; Sulaiman et al., 2003). An analysis of patients on a strict preventive regime together with IMRT found no cases of ORN (Ben-David et al., 2007). It is recommended that a dentist is attached to the head and neck team (NICE, 2004) or it may be the general dental practitioner who sees the patient. Either way, there should be a clear pathway of care and in order not to delay cancer treatment it is important the patient is seen urgently (Shaw et al., 1999). The purpose is twofold, to carry out treatment and to instigate a preventive programme during and after radiotherapy. Dental extractions Because dental extractions are a major risk factor in the development of ORN, in the past, extraction of all teeth before radiotherapy has been recommended. This is no longer the treatment of choice and has many disadvantages. Osteoradionecrosis occurs almost as frequently after pre-radiation extractions as post-radiation extractions (Chang et al., 2007). Clearly, any teeth causing pain or with infection should be extracted. Removal of all teeth of poor prognosis, generally considered less than five years, is recommended (Shaw et al., 1999), and planning should take into account the likely future problems with oral care, for example if severe trismus develops. The patient’s wishes must also be taken into account. Extractions are planned with the view to avoiding extractions in the future. Some have advocated removal of all mandibular molars in fields over 60 Gray, unless the patient has excellent oral hygiene (Johnson, 1997). An aggressive approach to extractions may not always be desirable, keeping teeth plays a significant role in maintaining chewing and swallowing function as well as quality of life in patients with cancer of the head and neck area (Allison et al., 1999). Consideration should also be give to the difficulty of wearing dentures after radiotherapy on account of trismus and xerostomia, and that denture trauma can cause ORN. Certain teeth may be essential for successful provision of a prosthesis to replace a surgical defect. Instead, a rigorous preventive programme is crucial for patients where teeth are retained. Teeth requiring extraction should be removed as soon as possible to permit maximum healing before radiotherapy. 06 Journal of Disability and Oral Health (2009) 11/1 Generally a minimum of ten days is recommended before commencement of radiotherapy (Clayman, 1997; Shaw et al., 1999), although some have recommended a minimum 14- 21 days (Sulaiman et al., 2003). However, it is undesirable to delay cancer treatment and since there is little difference between the risk of ORN whether extractions are pre- or post-radiation, and neither is it entirely preventable, radiotherapy should not be delayed. The extraction technique and experience of the operator has been debated as a factor in development of ORN. It is always recommended trauma is minimised (Sulaiman et al., 2003). Preventive regime Excellent tooth brushing is encouraged, if the mouth becomes too sore during radiotherapy a soft brush may be necessary for a time, supplemented with chlorhexidine mouthwash, which may be diluted with equal volume of water if too sore on the mucosa (Shaw et al., 1999). In addition a fluoride regime, either high fluoride toothpaste (Duraphat 5000), fluoride gel (Gel Kam) in splints for 10 minutes each day or alcohol free fluoride mouthrinse (Sulaiman et al., 2003). The regime needs to be tailored to the patient’s oral condition, for example, some patients are unable to open sufficiently for fluoride trays or to access the back of the mouth or there may be post surgical anaesthesia making brushing difficult. Altered taste and mucosal ulceration may mean some toothpastes or rinses are too strong for a time but the patient should return to the best regime as soon as possible. Motivation is very important and ideally the patient should see a dental hygienist who can monitor the patient during and after radiotherapy. Patients may be given several oral preparations to help with a sore or dry mouth and it is important the patient understands their function and avoids preparations which could harm the teeth. Saliva substitutes should be pH neutral. Some patients require frequent oral food supplements because of chewing and swallowing difficulties; these are very cariogenic. After radiotherapy Patients remain vulnerable to radiation caries and periodontal disease, especially if they have severe xerostomia or access for brushing is difficult. Restorative and periodontal treatment should be carried out where necessary, endodontic treatment is preferable to extraction, although this may be difficult or impossible where there is trismus. Unrestorable teeth may be decoronated. Dentures should be regularly checked for pressure areas and adjusted but it may be preferable to avoid dentures if the patient can manage with a shortened dental arch (Finlay et al., 1992). Extractions after radiotherapy Although undesirable, it may become necessary to extract teeth from the irradiated jaw. Kanatas et al. (2002) give a practical guide for extractions. The risk of ORN developing should be assessed, depending on the radiation dose, site and ease of extraction. Patients should be informed of the risk and be observant for early signs of ORN. Summary of recommendations: • 0.2% chlorhexidine mouthwash prior to extractions • Antibiotics 3g orally 1 hour pre extraction (or if allergic 600mg clindamycin) • Postoperative amoxicillin 250mg tds or metronidazole 200mg tds for 3-5 days • Minimal trauma, simple extraction of mobile teeth • Primary closure for firm teeth, by a minimal periosteal flap and alveolectomy • An experienced operator • Possibly pre-operative hyperbaric oxygen for mandibular molars in areas of high radiation • Review after 5 days, weekly review until healing is complete These recommendations are followed in most centres, although there is controversy about the best antibiotic regime and use of hyperbaric oxygen. Antibiotics Most studies on ORN have recommended antibiotic prophylaxis for extractions in post-radiation patients. A survey of British maxillofacial surgeons in 2002 found 86% recommended pre-surgical prophylaxis and 89% post-operative antibiotics for extraction of a mandibular molar in the radiotherapy field, although there was no consensus on the choice of antibiotic, timing and duration of course (Kanatas et al., 2002). Wahl (2006) found the incidence of ORN post-extraction after 1986 was 3.6% in cases using antibiotics and 2.6-3.4% in cases not reporting the use of antibiotics, indicating antibiotics appear to give no improvement in the rate of ORN. Antibiotics can have adverse side effects including gastrointestinal upset and risk of allergy for the patient. There is also a move to reduce the use of antibiotics to counter the development of resistant organisms. Antibiotic prescribing to prevent infection is increasingly controversial and some no longer recommend their use to prevent ORN (StevensonMoore and Epstein, 1993). Hyperbaric oxygen Hyperbaric oxygen (HBO) stimulates vascualisation and increased tissue oxygenation, encourages collagen and cell formation with improved healing (Kanaras et al., 2002). Since some studies indicated this may be effective in treating ORN consideration was given to its use in prevention. Marx et al. (1985) reported 5.4% ORN in patients who received HBO and antibiotics compared to 29.9% in patients who had antibiotics alone, for post-radiation dental extractions. A study in 1999 also showed favourable results with HBO (Vudiniabola et al., 1999), however, both these studies have a very high rate of ORN and small patient numbers. Burke and Fenlon: Osteoradionecrosis 07 Studies since 1986 have shown far lower rates of ORN, even without HBO (3.1-3.5%) and even a slightly higher rate for HBO patients (4.0%) (Whal, 2006). Some recommend the prophylactic use of HBO (David et al., 2001; Kanatas et al., 2002) and a Cochrane review suggested there was evidence for some reduction in ORN (Bennett et al., 2005) although others believe there is insufficient evidence to support its use for prophylaxis of ORN (Clayman, 1997). A survey of British maxillofacial surgeons found most recommended it as part of management but protocols varied (Kanatas et al., 2005). There are considerable difficulties with provision of HBO. The typical treatment regime is 20 dives before surgery and 10 afterwards, 90 minutes each, breathing 100% oxygen at high pressure in a chamber, so it is very time consuming. A course of treatment costs several thousand pounds and only a few centres are able to provide it. There are serious risks to the patient, including fits and ear damage as well as claustrophobia. Implant placement Patients who have had radiotherapy, especially if they have had additional extensive surgery, may have difficulty wearing a conventional denture. Implants are very useful in these situations. Hyperbaric oxygen has been recommended prior to implant placement to improve the success (Shaw et al., 1999; Kanatas et al., 2005) but a recent Cochrane review found no evidence for or against the use of HBO in this situation (Coultard et al., 2006). Treatment of osteoradionecrosis The course of ORN is variable. Sometimes ORN is symptomless and dental practitioners should therefore be observant for areas of exposed bone developing and take a careful history. Osteoradionecrosis can become very severe and debilitating but early intervention can lead to a good result. Patients should be managed in a maxillofacial unit. Conservative treatment for ORN usually involves smoothing sharp edges of necrotic bone and prolonged course of broad spectrum antibiotics (Kanatas et al., 2002; Reuther et al., 2003), either orally or intravenously. In one study antibiotic therapy and surgery led to complete healing in 40% of cases, the others continued as either a chronic or an aggressive form of ORN (Reuther et al., 2003). Surgery included local debridement and excision of necrotic bone with primary wound closure. In severe cases a block resection (with preservation of the lower border of the mandible) or a segmental resection with reconstruction with bone and skin grafts may be needed (Figure 3), (Yanagiya et al., 1993; Buchbinder and St Hilaire, 2006). It is important to be aware that recurrent disease can masquerade as ORN. In one study, seven of 33 cases initially diagnosed as ORN involved recurrent disease (Hao et al., 1999). Hyperbaric oxygen Hyperbaric oxygen therapy has been recommended in severe cases of ORN (Marx and Ames, 1982), often in combination with surgery. However, its effectiveness is uncertain. A randomised, double-blind trial in 2004 showed no benefit (Annane et al., 2004). Ultrasound Ultrasound stimulates the blood supply and bone metabolism and there has been some interest to assist healing of ORN. It has been applied to the mandible for ten minutes daily for 50 days with good results, although in a limited number of cases (Reher, 1997). Pentoxifylline and vitamin E Pentoxifylline (PTX) and vitamin E have been used to treat advanced cases of ORN, with promising results. These drugs are believed to promote healing, PTX lowers blood viscosity, increases tissue oxygen level, reduces fibroblast proliferation and increases collagenase activity; it is used to treat intermittent claudication. Vitamin E is an antioxidant. Pentoxifylline alone improved healing of radiation-induced mucosal injury (Futran et al., 1997) and one case of severe ORN of the sternum was completely healed with a combination of PTX, vitamin E and clodronate, which inhibits osteoclast activity (Delanian and Lefaix, 2002). A trial of 18 patients with severe ORN and oro-cutaneous fistulae was carried out in Paris 1995-2002 (Delanian et al., 2005). All these patients had failed to respond to conservative treatment, with or without HBO and surgery. The radiation dose was 55-75 Gray. Patients were given daily doses of 800mg PTX and 1000 IU vitamin E for at least six months The last eight patients treated also had 1600mg clodronate. Patient tolerance was very good. Quantitative regression of exposed bone was seen in 100% of patients by six months, and 89% had complete healing with mucosal coverage, most by six months. Qualitatively, assessment showed rapid pain relief, trismus reduction and closure of fistulae. These results, which are for patients for whom other treatments had failed, are promising. The drugs used were well tolerated and inexpensive (about £2 per day). Further clinical trials are necessary to assess the regime, including possible use as an early intervention measure or prophylactically and to study any long term side effects. Summary It is time to reconsider recommendation for prevention and management of ORN. Radiotherapy has improved and the incidence of ORN has reduced. Analysis of evidence for traditional preventive regimes of antibiotics or HBO does not consistently show any advantage, both have disadvantages and can no longer be wholeheartedly recommended. Similarly, in the management of established osteoradionecrosis, 08 Journal of Disability and Oral Health (2009) 11/1 HBO is of questionable benefit. Antibiotics with surgery if necessary lead to healing in some cases. Pentoxifylline and vitamin E may be a promising alternative conservative treatment and further studies are needed to evaluate them. Thorough pre-radiotherapy assessment, removal of teeth with poor prognosis and commencement of a preventive regime will reduce the need for dental extractions in the irradiated jaw. Patients are at high risk of oral disease following radiotherapy and should have frequent reviews and early intervention although the sequelae of surgery and radiotherapy can impose a challenge for the dentist. The continuation of preventive therapy is extremely important and the general dental practitioner has a vital role to play in the care pathway. For more complex cases, there is a place for development of specialist head and neck cancer care teams, including a dentist and dental hygienist. References Allison P, Locker D, Feine JS. The relationship between dental status and health-related quality of life in upper aerodigestive tract cancer. Oral Oncol 1999; 35: 138-143. 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Address for correspondence: Dr Mary Burke Department of Sedation and Special Care Dentistry King’s College London Dental Institute Floor 26, Tower Wing Great Maze Pond, London, SE1 9RT, UK [email protected]