Hyperbaric oxygen therapy in the treatment of radio-induced lesions in normal tissues: a literature review

Cerebral radiation necrosis: a review of the pathobiology, diagnosis and management considerations

Radiation therapy forms one of the building blocks of the multi-disciplinary management of patients with brain tumors. Improved survival following radiation therapy may come with a cost, including the potential complication of radiation necrosis. Radiation necrosis impacts the quality of life in cancer survivors, and it is essential to detect and effectively treat this entity as early as possible. Significant progress in neuro-radiology and molecular pathology facilitate more straightforward diagnosis and characterization of cerebral radiation necrosis. Several therapeutic interventions, both medical and surgical, may halt the progression of radiation necrosis and diminish or abrogate its clinical manifestations, but there are still no definitive guidelines to follow explicitly that guide treatment of radiation necrosis. We discuss the pathobiology, clinical features, diagnosis, available treatment modalities, and outcomes in the management of patients with intracranial radiation necrosis that follows radiation used to treat brain tumors.

Osteoradionecrosis and radiation dose to the mandible in patients with oropharyngeal cancer

PURPOSE

To determine the association between radiation doses delivered to the mandible and the occurrence of osteoradionecrosis (ORN).

METHODS AND MATERIALS

We reviewed the records of 402 oropharyngeal cancer patients with stage T1 or T2 disease treated with definitive radiation between January 2000 and October 2008 for the occurrence of ORN. Demographic and treatment variables were compared between patients with ORN and those without. To examine the dosimetric relationship further, a nested case-control comparison was performed. One to 2 ORN-free patients were selected to match each ORN patient by age, sex, radiation type, treatment year, and cancer subsite. Detailed radiation treatment plans for the ORN cases and matched controls were reviewed. Mann-Whitney test and conditional logistic regression were used to compare relative volumes of the mandible exposed to doses ranging from 10 Gy-60 Gy in 10-Gy increments.

RESULTS

In 30 patients (7.5%), ORN developed during a median follow-up time of 31 months, including 6 patients with grade 4 ORN that required major surgery. The median time to develop ORN was 8 months (range, 0-71 months). Detailed radiation treatment plans were available for 25 of the 30 ORN patients and 40 matched ORN-free patients. In the matched case-control analysis, there was a statistically significant difference between the volumes of mandible in the 2 groups receiving doses between 50 Gy (V50) and 60 Gy (V60). The most notable difference was seen at V50, with a P value of .02 in the multivariate model after adjustment for the matching variables and dental status (dentate or with extraction).

CONCLUSIONS

V50 and V60 saw the most significant differences between the ORN group and the comparison group. Minimizing the percent mandibular volume exposed to 50 Gy may reduce ORN risk.

Effects of hyperbaric oxygen on aggressive periodontitis and subgingival anaerobes in Chinese patients

OBJECTIVE

To investigate the effects of hyperbaric oxygen (HBO2) on aggressive periodontitis (AgP), and subgingival obligate anaerobes in Chinese patients.

MATERIALS AND METHODS

Sixty cases of Chinese patients with AgP were randomly divided into two groups -the HBO2 group (30 cases) and the control group (30 cases). Study teeth were divided into four groups -: the HBO2 therapy, the HBO2 + scaling scaling group, the scaling group and the control group. Subgingival anaerobic organisms were measured with anaerobic culture, and number of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus was counted. Comparisons of changes in the clinical indices, and subgingival anaerobes were made between the groups.

RESULTS

Highly significant differences in gingival index (GI), probing depth (PD), attachment loss (AL), and Plaque index (PLI), and tooth odontoseisis (TO) were seen in the HBO2, the HBO2 + scaling and the scaling groups when compared with the control group (P<0.01). The number of subgingival anaerobes as well as the types of obligate anaerobes and facultative anaerobes and the number of Bacteroides melaninogenicus were reduced markedly in these three treatment groups. Highly statistical differences in clinical indices, subgingival anaerobe number and types of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus were found when comparisons were made between the HBO2 + scaling and the HBO2 groups, as well as between the HBO2 + scaling and the scaling groups. Clinical follow-ups indicated that the GI, PD, AL, TO, PLI and subgingival anaerobes number of the three therapeutic groups were reduced more severely than the control group.

CONCLUSIONS

HBO2 had good therapeutic effects on Chinese patients with AgP. HBO2 therapy combined with scaling and root planing was the most beneficial in the treatment of AgP. The therapeutic effect of HBO2 on AgP is most likely through inhibition of the growth of subgingival anaerobes. Clinical follow-ups suggest that the effect could last more than 2 years.

Successful hyperbaric oxygen therapy for laryngeal radionecrosis after chemoradiotherapy for mesopharyngeal cancer: case report and literature review

Laryngeal radionecrosis is one of the most troublesome late complications of radiotherapy, because it is frequently resistant to treatment and laryngectomy is required in the worst case. Here, we report a case of laryngeal radionecrosis, successfully treated by use of hyperbaric oxygen (HBO) therapy, in which laryngectomy was avoided. A 67-year-old male received radical chemoradiotherapy (CRT) for mesopharyngeal cancer, which included radiotherapy with a total dose of 71.4 Gy/38 Fr and chemotherapy with CDDP + S-1. He developed dyspnea and throat pain 9 months after completion of CRT. Laryngoscopy revealed vocal cord impairment because of severe laryngeal edema. He was diagnosed as having laryngeal radionecrosis and initially received conservative therapy combined with antibiotics, steroids, and prostaglandins. Because his dyspnea was persistent despite this treatment, HBO therapy was administered 20 times, and resulted in complete remission of the dyspnea. HBO therapy, therefore, is regarded as an effective conservative therapeutic option for laryngeal radionecrosis.

Beneficial effect of hyperbaric oxygen therapy on the follicular survival in the mouse ovary after transplantation

A large proportion of follicles are lost during the initial ischemia that occurs after transplantation of ovarian tissues. Thus, the effect of hyperbaric oxygen therapy (HBO) on the follicular loss of ovarian tissues after transplantation was examined in mice. Ovarian slices from ICR mice were transplanted under the kidney capsule in ovariectomized ICR. Hyperbaric oxygen with 100% oxygen was initiated for 30 min at 2.5 atmospheres absolute immediately after transplantation, and this treatment was repeated at 48-h intervals for 2 weeks. The number of follicles was dramatically reduced at 2 weeks post transplantation. However, HBO was significantly effective in enhancing the survival of transplanted ovarian follicles. The survival rates of primordial and primary follicles in ovarian tissues of mice with HBO were significantly higher than those without HBO. These results indicate HBO can be effectively used for the enhancement of survival of transplanted ovarian tissues.

Hemorrhagic cystitis: A challenge to the urologist

Severe hemorrhagic cystitis often arises from anticancer chemotherapy or radiotherapy for pelvic malignancies. Infectious etiologies are less common causes except in immunocompromised hosts. These cases can be challenging problems for the urologist and a source of substantial morbidity and sometimes mortality for the patients. A variety of modalities of treatment have been described for the management of hemorrhagic cystitis but there is none that is uniformly effective. Some progress has been made in the understanding and management of viral hemorrhagic cystitis. This article reviews the common causes of severe hemorrhagic cystitis and the currently available management options.

Management of refractory hemorrhagic cystitis following hematopoietic stem cell transplantation in children

HC is a complication associated with HSCT, but occurs rarely in solid organ recipients. The reported incidence varies from <10% to more than 70%. HC is characterized by hemorrhagic inflammation in urinary tract mucosa with symptoms varying from asymptomatic microscopic hematuria to frank hematuria with clot formation and urinary tract obstruction. Early onset HC may be explained by toxicity of chemo- and/or radiotherapy, while multiple factors including viral infections and their interplay seem to be involved in late onset HC. So far, only incidence of cyclophosphamide-associated HC has been reduced with preventive treatment. Likely, once HC is established, the treatment principles are similar regardless of the etiology and depend on the intensity of HC. Prevention of urinary tract obstruction, transfusion support, analgesic, and spasmolytic therapy are generally accepted in HC management. Treatment beyond this conservative approach entails higher risk for side effects, and thus treatment escalation proportional to HC intensity is warranted. No standard and evidence-based treatment escalation algorithm has been widely adopted yet. As severe HC following HSCT is a potentially life-threatening complication, a multidisciplinary and individual approach is required in children suffering from this devastating complication.

Prevention and treatment of trismus in head and neck cancer: A case report and a systematic review of the literature

Introduction

Trismus, or limited mouth opening, is a well-known complication of head and neck cancer and its treatment. It may be caused by tumour infiltration into the masticatory muscles or by treatment like surgery and radiotherapy. A limited mouth opening may have a negative effect on nutrition, phonation, dental hygiene and treatment, and quality of life. The severity of this complication depends on the location of the tumour, the type of reconstruction, the total radiation dose, fractionation, and treatment techniques. If there is no intervention, these changes may be progressive and persist for life. There are no specific treatments for trismus. Current strategies emphasize prevention and, in instances of existing trismus, collaboration between health care professionals to establish pain control, prevent the progression of trismus, and restore function. The prevalence of trismus in head and neck cancer patients ranges from 5% to 38%. Despite numerous studies, reliable data on the aetiology of trismus and appropriate treatment for it are scarce.

Case report

We describe a patient with squamous cell carcinoma of the oropharynx who developed trismus after surgery and radiotherapy. A multidisciplinary treatment strategy including analgesics, regional blocks, hyperbaric oxygenation therapy, external dynamic bite opener and physiotherapy, increased the mouth opening from 5 mm to 22 mm, however, the patient still suffered from xerostomia and had problems with intake of solid food.

Material and methods

A systematic literature search (starting January 1., 1980, and ending June 1., 2009) was performed to identify evidence-based interventions for the treatment of trismus in head and neck cancer patients. A total of 244 articles were identified from the databases. Of these, eight were excluded because of the absence of an English abstract and 214 were excluded because they were of marginal relevance to the inclusion criteria. The remaining 22 articles were evaluated independently by two experts using the Scottish Inter-collegiate Guidelines Network criteria for quality and evidence.

Results

There were few studies of good methodological quality on this topic. Two systematic reviews and two RCTs were identified. The other reports involved cohorts, case series, and expert opinions.

Discussion

Evidence in the form of clinical studies on therapeutic interventions is scarce. Numerous pharmacological treatment modalities have been described, but few are supported by the results of comparative trials involving control groups. Few studies have documented therapeutic effects for longer than a year. Better evidence was found for non-pharmacological methods, especially for physical therapy with passive and active stretching exercises, an important first-line strategy. The interincisal distance criterion for trismus varies between authors from 15 to 40 mm, which renders comparison between studies difficult. The absence of a standardized assessment protocol may also have contributed to variation between studies. An interincisal distance of 35 mm has been proposed as a definition of trismus. Explicit and precise treatment algorithms could not be established based on the available literature. However, a coordinated multidisciplinary approach in order to estimate and understand patient dysfunction is recommended; a systematic treatment plan should result in good symptom control and patient care. Prevention of trismus is more desirable than treatment for trismus.

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

PURPOSE

The aim of this paper is to explore the current theories about definition, classification, incidence and physiopathology of osteoradionecrosis (ORN) of the jaws. Moreover, it is discussed the predisposing and risk factors for the development of osteoradionecrosis based on the literature review.

DISCUSSION

Osteoradionecrosis is one of the most serious oral complications of head and neck cancer treatment. Osteoradionecrosis is a severe delayed radiation-induced injury, characterised by bone tissue necrosis and failure to heal. Osteoradionecrosis either stabilises or gradually worsens and is notoriously difficult to manage. The most widely accepted theory to explain its cause until recently was the theory of hypoxia, hypovascularity and hypocellularity. A new theory for the pathogenesis of osteoradionecrosis was proposed. The clinical presentations of osteoradionecrosis are pain, drainage and fistulation of the mucosa or skin that is related to exposed bone in an area that has been irradiated. The tumour size and location, radiation dose, local trauma, dental extractions, infection, immune defects and malnutrition can predispose its development.

CONCLUSIONS

A better understanding of risk factors for the development ORN and of the underlying pathophysiology may improve our ability to prevent this complication and help to improve the prognosis for those being treated for osteoradionecrosis.

Hyperbaric oxygen therapy for late radiation tissue injury in gynaecological patients

BACKGROUND

Pelvic radiation therapy is an important element of curative therapy for gynaecological cancers. Serious radiation-related complications developing months or years after treatment are known as late radiation tissue injury (LRTI).

METHODS

We investigated the possible pain reducing effect of hyperbaric oxygen treatment (HBOT) in a study of 16 patients with LRTI after radiation for gynaecological malignancy. The 16 patients were registered prospectively, underwent HBOT for 21 consecutive days and were followed for a 6-month period after treatment using the Brief Pain Inventory, Montgomery and Aasberg Depression Rating Scale, as well as registration of global patient scores, analgesic consumption and magnetic resonance imaging (MRI) findings.

RESULTS

HBOT was shown to have insignificant effect on pain, pain characteristics, daily function, the use of analgesics and MRI-related tissue injury. Fifty percent of the patients still reported some or good effect of the treatment.

CONCLUSION

It is not possible to conclude from our study if gynaecological patients with pelvic pain will benefit from HBOT. The application of HBOT to selected patients may be justified, but further research with adequate sample size, as well as the timing of HBOT related to the development of LRTI, is required to establish the optimum patient selection.

Modification of glucose metabolism in radiation-induced brain injury areas using cervical spinal cord stimulation

PURPOSE

Radiation-induced brain injury (RBI) is an insidious side-effect of radiotherapy mediated by vascular alterations, inflammation and ischaemia. In previous studies we had shown potential increases in loco-regional blood flow and glucose metabolism in brain tumours by using electrical cervical spinal cord stimulation (SCS). In this preliminary report we demonstrate the effect of cervical SCS on RBI-tissue metabolism, as assessed using [(18)F]fluorodeoxyglucose-positron emission tomography (FDG-PET).

METHODS

SCS devices were inserted in eight patients with diagnosis of potential RBI in previously irradiated areas. While the SCS device was deactivated, each patient underwent an initial FDG-PET study to evaluate the clinical status. A second FDG-PET study was performed later the same day while the SCS device was activated in order to evaluate the effect of cervical SCS on glucose metabolism.

RESULTS

Basal glucose metabolism in RBI areas was 31% lower than peri-RBI areas (p = 0.009) and 32% lower than healthy contra-lateral areas (p = 0.020). There was a significant increase in glucose uptake during SCS in both the RBI (p = 0.005) and the peri-RBI (p = 0.004) areas, with measured increases of 38 and 42%, respectively. The estimated potential maximal residual activity of the first FDG dose's contribution to the activity on the second scan was <or=14.3 +/- 4.6%.

CONCLUSIONS

In this study using PET, SCS increased glucose metabolism in RBI and peri-RBI areas. These results warrant further clinical investigation to elucidate more fully the clinical usefulness of SCS in these patients.

A randomized prospective study of extended tocopherol and pentoxifylline therapy, in addition to carbogen, in the treatment of radiation late effects

Purpose:

pentoxifylline (PTX) and tocopherol (vitamin E) are antioxidants previously shown to be useful in combination in the treatment of late radiation induced toxicity. The purpose of this study was to investigate the benefit of combination therapy with carbogen pentoxifylline and tocopherol in the mitigation of late radiation effects. As the optimal duration of PTX and tocopherol treatment has not been fully established, we studied short versus extended treatment duration.

Methods:

we conducted a phase II prospective randomized study of short versus prolonged treatment with pentoxifylline (800 mg) and tocopherol (1000 IU) orally once daily in patients with grade three toxicity post-radical radiotherapy. In addition, all 18 patients received inhaled carbogen (95% O + 5% CO₂) over 90 minutes, five days/week, for three weeks. The primary end point was improved in maximum Lent-Soma toxicity scores.

Results:

maximum Lent-Soma scores improved in six of the 18 patients (response rate 33%). The proportion of patients responding to treatment in the prolonged treatment arm B was more than double than in the shorter arm A, but this did not reach statistical significance (p=0.321). Two patients who had prolonged treatment (arm B) had complete resolution of their symptoms, which was maintained at two and three year follow-ups.

Conclusions:

we recommend prolonged treatment for 12 months, with PTX and tocopherol in combination with carbogen therapy, in the management of late radiation effects.

Improved quality of life with hyperbaric oxygen therapy in patients with persistent pelvic radiation-induced toxicity

AIMS

We report the results of hyperbaric oxygen therapy (HBOT) used in the treatment of radiation-induced persistent side-effects after the irradiation of pelvic tumours.

MATERIALS AND METHODS

Between January 2001 and December 2005, 13 women (median age 60.3 years) with radiation combined proctitis/cystitis (n=6), longstanding vaginal ulcers and fistulas (n=5) and longstanding skin injuries (n=2) underwent HBOT in a multiplace chamber for a median of 27 sessions (range 16-40). The treatment schedule was HBOT 100% oxygen, at 2 absolute atmospheres, for 90 min, once a day. For radiation-induced toxicity grading we used the National Cancer Institute Common Toxicity Criteria (CTC) grading system, before and after HBOT.

RESULTS

Thirteen patients underwent an adequate number of HBOT sessions. The mean CTC grading score before HBOT was 3.3+/-0.75, whereas the mean CTC grading score after HBOT was 0.3+/-0.63. The scores showed a significant improvement after HBOT (P=0.001; exact Wilcoxon signed-rank test). Rectal bleeding ceased in five of six patients with proctitis and dysuria resolved in six of seven cystitis patients. Macroscopic haematuria stopped in seven of seven patients. Scar complications resolved in two of two patients. None reported HBOT-associated side-effects.

CONCLUSION

HBOT is apparently safe and effective in managing radiation-induced late side-effects, such as soft tissue necrosis (skin and vagina), cystitis, proctitis and fistulas.

Current Management for Late Normal Tissue Injury: Radiation-Induced Fibrosis and Necrosis

Radiation-induced fibrosis (RIF) and radionecrosis (RN) are late complications that are usually considered irreversible. Usual management strategy includes eliminating local and general aggravating factors and controlling acute and chronic inflammation with steroids. Thanks to progress in understanding the pathophysiology of these lesions, several lines of treatment have been developed in clinical practice. However, results of clinical studies are difficult to compare because of variations in severity of RIF, method of RIF assessment, availability of efficient therapeutic drugs, treatment duration, and quality of trial design. For moderate established RIF, current management strategy mainly includes (1) anti-inflammatory treatment with corticosteroids or interferon gamma; (2) vascular therapy with pentoxifylline (PTX) or hyperbaric oxygen (HBO); and (3) antioxidant treatment with superoxide dismutase, tocopherol (vitamin E), and, most successfully, with a PTX-vitamin E combination. On the basis of etiology, RN can be managed by (1) anti-inflammatory treatment with corticosteroids and possibly clodronate, (2) vascular therapy with HBO and PTX, (3) antioxidant treatment with a PTX-vitamin E combination, and (4) a PTX-vitamin E-clodronate combination. Controlled randomized trials are now necessary to identify the best treatment at each step of RIF. In the future, these treatments of fibrosis and necrosis should include targeted drugs (such as growth factors) to take organ specificities into account.

Hyperbaric oxygen therapy and liver transplantation

Liver transplantation is the treatment of choice for end stage liver disease and is often used for primary liver malignancies. The main limitation of its wider application is the availability of suitable donor organs. The use of marginal donor organs, split-liver transplantation and living-related liver transplantation techniques contribute to increase the donor pool. However, the use of these techniques is associated with a higher risk of post transplantation organ dysfunction, predominantly due to ischaemia, preservation and reperfusion injury (IPRI). A number of studies have demonstrated that hyperbaric oxygen (HBO) therapy influences IPRI and consequential acute cellular rejection. This article reviews the rationale of HBO therapy in the field of transplantation with particular emphasis on liver transplantation.

Oncologic Emergencies

It has been estimated that genitourinary malignancies will account for 25% of new cancer diagnoses in the United States in 2005 (Jemal et al. 2005). While the incidence of many of these malignancies has increased over the past two decades, the mortality rates appear to be decreasing. Early cancer detection combined with improvements in surgical and nonsurgical oncologic therapy account for these trends. Although not common, newly diagnosed cancer patients occasionally present in an emergent, life-threatening manner that warrants immediate medical or surgical intervention. As the prevalence of genitourinary malignancies continues to expand, additional patients can be expected to develop disease or treatment-related complications. This chapter will serve to review the diagnosis and management of oncologic emergencies as they pertain to the urologist.

Treatment of a radiation-induced rectal ulcer with hyperbaric oxygen therapy in a man with prostate cancer

Late radiation proctopathy is a painful and vexing complication of prostate radiation. We report a case of a 55-year-old man with prostate cancer, and complaints of tenesmus and severe rectal pain after radiation therapy. The patient was diagnosed with a locally advanced Gleason score 8 prostate cancer and an increased prostate-specific antigen of 42.3 ng/ml. His past medical history was notable for a history of bilateral lymph node dissection complicated by Clostridium difficile colitis. He subsequently received 3-dimensional conformal radiation therapy. Seven months after completing therapy, minor rectal bleeding and significant pain developed, requiring increasing doses of opioid analgesics. Fourteen months after 3-dimensional conformal radiation therapy, sigmoidoscopy revealed a single chronic deep ulcer at the anorectal junction. As an alternative to diverting colostomy, the patient underwent a course of hyperbaric oxygen. Within 1 month of completing hyperbaric oxygen treatment, his symptoms completely resolved. Nine months from completion of hyperbaric oxygen therapy, he has had no recurrence of symptoms. Hyperbaric oxygen therapy can be considered a treatment option after failure of standard treatments in patients with severe radiation proctopathy.

Infected osteoradionecrosis of the mandible: follow-up study suggests deterioration in outcome for patients with Actinomyces-positive bone biopsies

Infected osteoradionecrosis (IORN) is one of the major complications of oral cancer radiotherapy. Recent studies showed a high prevalence of Actinomyces in IORN. In this study, the clinical follow up of IORN patients (n=25; 20 male, 5 female) with regard to Actinomyces detection in the mandible was analyzed. Within 1.6-119 months of follow up, disease control was achieved in almost 90% of the patients with Actinomyces-negative bone biopsies, but only in 25% of the Actinomyces-positive group. The presence of Actinomyces was associated with a significantly higher risk of treatment failure (P=0.004; Fisher's exact test). This held true when the data were controlled for 'extent of bone destruction', 'type of surgery' and 'soft-tissue closure' in a logistic regression analysis (P=0.018; Wald test). Since Actinomyces was detected in a significant number of patients with non-healing mucosal defects, this microbe may promote the persistence of chronic non-healing inflammatory processes. Actinomyces positivity defines a subpopulation with a clinically deteriorated course of mandibular IORN.

Safety and Efficacy of Hyperbaric Oxygen Therapy for the Treatment of Interstitial Cystitis: A Randomized, Sham Controlled, Double-Blind Trial

PURPOSE

We conducted a double-blind, sham controlled study to evaluate the safety, efficacy and feasibility of hyperbaric oxygenation for interstitial cystitis.

MATERIALS AND METHODS

A total of 21 patients with interstitial cystitis were randomized to 90 minutes treatment in a hyperbaric chamber pressurized with 100% O2 to 2.4 atmosphere absolute for 30 treatments sessions or 1.3 atmosphere absolute, breathing normal air in the control group. Moderate or marked improvement in a global response assessment questionnaire was defined as treatment response (primary outcomes). Secondary measurements included changes of pain and urgency evaluated by visual analog scales, functional bladder capacity and frequency. Changes in the O'Leary-Sant Interstitial Cystitis Index and rating of overall satisfaction with the therapeutic outcome were also reported.

RESULTS

There were 3 of 14 patients on verum and no control patients who were identified as responders (p < 0.52) [corrected] At 12-month followup 3 patients (21.4%) still reported treatment response. Hyperbaric oxygenation resulted in a decrease of baseline urgency intensity from 60.2 +/- 15.0 to 49.9 +/- 35.2 mm at 3 months and decrease of pain intensity from 43.1 +/- 20.5 to 31.2 +/- 19.8 mm, respectively (p < 0.05). The Interstitial Cystitis Symptom Index score sum decreased from 25.7 to 19.9 points in patients on verum. Sham treatment did not result in improvement of the baseline parameters.

CONCLUSIONS

A total of 30 treatment sessions of hyperbaric oxygenation appear to be a safe, effective and feasible therapeutic approach to interstitial cystitis. In the treatment responders application of hyperbaric oxygenation resulted in a sustained decrease of interstitial cystitis symptoms with a discordant profile regarding the peak amelioration of the various interstitial cystitis symptoms compared with a normobaric, normoxic sham treatment.

Oral complications of radiotherapy

Radiotherapy-induced damage in the oral mucosa is the result of the deleterious effects of radiation, not only on the oral mucosa itself but also on the adjacent salivary glands, bone, dentition, and masticatory musculature and apparatus. Biological response modifiers, cytoprotective drugs, salivary-sparing radiation techniques, and surgery have been introduced to combat and, more importantly, to prevent, the development of these complications. Radiotherapy-induced oral complications are complex, dynamic pathobiological processes that lower the quality of life and predispose patients to serious clinical disorders. Here, we focus on these oral complications of radiotherapy, highlight preventive and therapeutic developments, and review the current treatment options available for these disorders.

Treatment of radiation proctitis with hyperbaric oxygen

BACKGROUND AND PURPOSE

Radiation proctitis is a potential complication following pelvic radiation therapy. There are no standard treatments and treatment outcomes are unpredictable. We report our experience with the use of hyperbaric oxygen treatment (HBOT) for radiation proctitis cases refractory to standard medical or laser therapy.

PATIENTS AND METHODS

During the period 2000-2004, 10 patients with radiation proctitis were treated with HBOT (three males and seven females; mean age of 65). The median follow-up period was 25 months (range 6-43 months). Patient symptoms were retrospectively scored prior to, and following HBOT, based on the LENT-SOMA scale.

RESULTS

Prior to treatment, three patients had Grade 3 toxicity (i.e. requiring blood transfusions) and seven had Grade 2 toxicity with dominant symptoms of rectal pain and/or diarrhoea. HBOT was well tolerated and 9 of the 10 patients completed a full HBOT treatment program. Rectal bleeding completely stopped in four of nine symptomatic patients and improved in three others. Rectal pain completely remitted in three of five symptomatic patients. Diarrhea remitted completely in one of five patients and improved in three others. Of the 10 patients treated, only two did not respond to HBOT.

CONCLUSIONS

Significant improvement of rectal bleeding, diarrhea and rectal pain is possible using HBOT. HBOT should be offered to patients who fail conventional treatments for radiation proctitis.

Osteoradionecrosis of the cervical spine resulting from radiotherapy for primary head and neck malignancies: operative and nonoperative management

✓ Osteoradionecrosis is a process of dysvascular bone necrosis and fibrous replacement following exposure to high doses of radiation. The poorly vascularized necrotic tissue may cause pain and/or instability, and it cannot resist infection well, which may result in secondary osteomyelitis. When these processes affect the cervical spine, the resulting instability and neurological deficits can be devastating, and immediate reestablishment of spinal stability is paramount. Reconstruction of the cervical spine can be particularly challenging in this subgroup of patients in whom the spine is poorly vascularized after radical surgery, high-dose irradiation, and infection. The authors report three cases of cervical spine osteoradionecrosis following radiotherapy for primary head and neck malignancies. Two patients suffered secondary osteomyelitis, severe spinal deformity, and spinal cord compression. These patients underwent surgery in which a vascularized fibular graft and instrumentation were used to reconstruct the cervical spine; subsequently hyperbaric oxygen (HBO) therapy was instituted. Fusion occurred, spinal stability was restored, and neurological dysfunction resolved at the 2- and 4-year follow-up examinations, respectively. The third patient experienced pain and dysphagia but did not have osteomyelitis, spinal instability, or neurological deficits. He underwent HBO therapy alone, with improved symptoms and imaging findings. Hyperbaric oxygen is an essential part of treatment for osteoradionecrosis and may be sufficient by itself for uncomplicated cases, but surgery is required for patients with spinal instability, spinal cord compression, and/or infection. A vascularized fibular bone graft is a very helpful adjunct in these patients because it adds little morbidity and may increase the rate of spinal fusion.

Osteoradionecrosis of the mandible

PURPOSE OF REVIEW

Osteoradionecrosis of the mandible is a serious complication of radiation therapy to the head and neck. Given the increased use of radiation therapy and combined chemotherapy-radiation therapy regimens in treatment of head and neck malignancies, it is anticipated that osteoradionecrosis will continue to be an important clinical problem. Recently, new concepts have been introduced regarding the pathogenesis of osteoradionecrosis, and these ideas help outline new guidelines for treatment.

RECENT FINDINGS

Current literature focuses on the probability of a fibroatrophic mechanism for the development of osteoradionecrosis, rather than the traditional vascular insufficiency mechanism. Because of the evolution of this new idea, as well as a double-blinded, placebo-controlled study finding no benefit from the use of hyperbaric oxygen for advanced osteoradionecrosis of the mandible, new treatment considerations have emerged. Ongoing research is also being conducted to clarify the role of osteoclasts in the pathogenesis of osteoradionecrosis. Restoration of blood supply or vascularized tissue to the affected area continues to be of primary importance in the resolution of osteoradionecrosis.

SUMMARY

It is clear that the cause and pathogenesis of osteoradionecrosis are far more complex than originally believed. Current and future research on this multifaceted topic will focus on the cellular basis of this condition, because as it is elucidated, more effective medical treatment regimens will become evident.

The radiation-induced fibroatrophic process: therapeutic perspective via the antioxidant pathway

The radiation-induced fibroatrophic process (RIF) constitutes a late, local and unavoidable sequela to high-dose radiotherapy, traditionally considered irreversible. Today, this process is partly reversible, thanks to recent progress in understanding the physiopathology of the lesions it causes and the results of recent clinical trials using antioxidant therapy. This review includes a synthetic description of the static and dynamic features of the RIF process, as reflected by its clinical, instrumental and histopathological characteristics, and by its cellular and molecular regulation. Schematically, three successive clinical and histopathological phases can be distinguished: a pre-fibrotic aspecific inflammatory phase, a constitutive fibrotic cellular phase, and a matrix densification and remodelling phase, possibly ending in terminal tissular necrosis. The respective roles of the chief actors in the RIF process are defined, as well as their development with time. A fibroblastic stromal hypothesis is suggested revolving around a 'gravitational effect' exerted by the couple ROS (reactive oxygen species)--fibroblasts, and partly mediated by TGF-beta1. A variety of strategies have been tested for the management of RIF. In the light of the mechanisms described, a curative procedure has been proposed via the antioxidant pathway. In particular, it was showed that superoxide dismutase and combined pentoxifylline-tocopherol treatment enables the process of established radiation-induced fibroatrophy to be greatly reduced or even reversed, both in clinical practice and animal experiments. The efficacy of combined pentoxifylline-tocopherol treatment in superficial RIF was confirmed in a randomised clinical trial, and then in successful phase II trials especially in uterine fibroatrophy and osteoradionecrosis. It is of critical importance to evaluate these new management approaches in larger clinical trials and to improve the recording of results for better outcome analysis. Mechanistic studies are always necessary to improve understanding of the RIF process and the antifibrotic drug action.