Monitoring the genotoxic effects of radiosynovectomy with Re-186 in paediatric age group undergoing therapy for haemophilic synovitis

Is micronucleus assay a suitable method for biomonitoring children exposed to X-ray? A systematic review with meta-analysis

PURPOSE

The aim of this study was to evaluate if the micronucleus test using oral epithelial cells is a suitable biomarker for biomonitoring children exposed to X-ray.

MATERIAL AND METHODS

A search was performed through the electronic databases PubMed/Medline, Scopus, and Web of Science, all studies published up to February 2022 that examined the relationship between exposure of children to radiographic examinations and micronucleus.

RESULTS

A total of 17 full-text manuscripts were screened for eligibility. Only two studies found a difference in micronucleus labeling. On the other hand, all studies showed that X-ray was able to induce cellular death in oral mucosa cells. Following the parameters of the Effective Practices in Public Health Project (EPHPP), five manuscripts reached moderate and strong scores, and four studies were categorized as weak at final rating. In the meta-analysis, statistically significant difference was detected in micronucleated cells in children before and after radiographic examinations (SMD = 0.96, 95% CI, 0.07-1.84, p = .04), with τ2=1.09; χ2=53.37, and p < .001.

CONCLUSION

Radiographic examinations in children can cause genotoxic and cytotoxic damage in the oral epithelium with a large effect size.

The value of radiosynoviorthesis for treatment of chronic synovitis in hemophilic joint disease

Chronic synovitis is contributing to the development of arthropathy in hemophilia A and B. In most patients with severe and moderate hemophilia, during lifetime, joint damage progresses despite early prophylaxis and intense treatment with coagulation factor concentrates. Recurrent hemorrhages into the joints and subclinical bleeding lead to chronic inflammation of the synovium, neoangiogenesis and remodeling, sustaining a vicious circle of bleeding-remodeling-bleeding and progression of osteochondral damage. Imaging techniques including ultrasound and MRI are able to early visualize synovitis and osteochondral changes. Early detection and sustained therapy of synovitis are important preconditions to prevent further deterioration of joint status. Chronic synovitis requires intensified substitution of coagulation factors and concomitant analgetic, antiphlogistic and physical therapy. The value of early radiosynoviorthesis (RSO) as effective method to control ongoing synovitis is discussed here. RSO is recommended as first choice therapy in case of persistant chronic synovitis, recorded in both national and international guidelines.

The EANM guideline for radiosynoviorthesis

Purpose

Radiosynoviorthesis (RSO) using the intraarticular application of beta-particle emitting radiocolloids has for decades been used for the local treatment of inflammatory joint diseases. The injected radiopharmaceuticals are phagocytized by the superficial macrophages of the synovial membrane, resulting in sclerosis and fibrosis of the formerly inflamed tissue, finally leading to reduced joint effusion and alleviation of joint pain.

Methods

The European Association of Nuclear Medicine (EANM) has written and approved these guidelines in tight collaboration with an international team of clinical experts, including rheumatologists. Besides clinical and procedural aspects, different national legislative issues, dosimetric considerations, possible complications, and side effects are addressed.

Conclusion

These guidelines will assist nuclear medicine physicians in performing radiosynoviorthesis. Since there are differences regarding the radiopharmaceuticals approved for RSO and the official indications between several European countries, this guideline can only give a framework that must be adopted individually.

Dosimetry perspectives in radiation synovectomy

Rheumatoid arthritis (RA) is a chronic inflammatory disease that can potentially damage the synovial joints. One of the effective treatment modality for RA is radiation synovectomy (RSV) where properly selected radionuclide is injected into the joint space, enabling controlled destruction of diseased synovial membrane via radiation exposure. Radiation dosimetry in RSV appears challenging due to the heterogeneous nature of synovial membrane, nonuniform distribution and leakage of radionuclide from the synovial cavity. This article reviews the dosimetric perspective pertaining to RSV. Specifically, characteristics of radionuclide for RSV and radiation dose to target and non-target (i.e., articular cartilage, bone, bloodstream, gonads, etc.) tissues of patient have been discussed. The personal dose H_p(0.07) to the hands of medical staff (i.e., radiochemist, therapist physician, nurse) may be considerably high due to handling of high specific activities (∼500 MBq/ml for Y-90); such doses are typically measured using thermoluminescence dosimeters (TLD) ring dosimeters and ranges from 1 to 21.5, 0.1 to 40 and 0.1 to 5 µSv/MBq for the radiochemist, therapist physician and the nurse, respectively. Methods to minimize radiation doses to the patient, medical staff and public are elaborated. Contamination risks and precautionary measures are also reported.

Current role for radioisotope synovectomy

Radioisotope synovectomy has been extensively used to treat patients with chronic inflammatory joint disease but has moved to a less prominent position since the introduction of new and highly effective drugs. Remaining indications are refractory synovitis, pigmented villonodular synovitis as an adjunct to surgery, and hemophilic arthropathy. The three main radioisotopes used are yttrium-90, rhenium-186, and erbium-189. Radioisotope synovectomy should be performed only by highly experienced professionals, to minimize the risk of injection-related complications. The available safety data, in particular regarding the risk of malignancy, are reassuring. The efficacy of yttrium-90 in chronic inflammatory joint disease remains controversial.

Therapeutic radionuclides in nuclear medicine: current and future prospects

The potential use of radionuclides in therapy has been recognized for many decades. A number of radionuclides, such as iodine-131 ((131)I), phosphorous-32 ((32)P), strontium-90 ((90)Sr), and yttrium-90 ((90)Y), have been used successfully for the treatment of many benign and malignant disorders. Recently, the rapid growth of this branch of nuclear medicine has been stimulated by the introduction of a number of new radionuclides and radiopharmaceuticals for the treatment of metastatic bone pain and neuroendocrine and other malignant or non-malignant tumours. Today, the field of radionuclide therapy is enjoying an exciting phase and is poised for greater growth and development in the coming years. For example, in Asia, the high prevalence of thyroid and liver diseases has prompted many novel developments and clinical trials using targeted radionuclide therapy. This paper reviews the characteristics and clinical applications of the commonly available therapeutic radionuclides, as well as the problems and issues involved in translating novel radionuclides into clinical therapies.

Safety of radiation exposure after radiosynovectomy in paediatric patients with haemophilia

Many paediatric patients with haemophilia who might benefit from radiosynovectomy (RS) for the control of synovitis do not undergo the procedure as there is controversy in the literature regarding the safety of radiation exposure after two cases of acute lymphocytic leukaemia in children with haemophilia treated with (32) P RS were reported. The purpose of this review was to analyse the safety of RS in paediatric patients with haemophilia and provide a risk-benefit assessment, which practitioners could apply to their patients. Children undergoing knee RS receive a radiation dose of approximately 0.74 mSv (90 megabecquerels-MBq) and elbow and ankle RSs a dose of approximately 0.32 mSv (30-40 MBq). The radiation dose from natural sources is approximately 2 mSv and the recommended limit for patients (apart from natural sources) is 1 mSv per year. The lifetime cancer risk increases about 0.5% per 100 mSv per year. Considering the risks and benefits of RS, the authors recommend that clinicians consider this procedure in children with inhibitors or in patients without inhibitors when bleeding is recurrent and persistent despite aggressive factor replacement.

Radiosynovectomy in hemophilic synovitis

Radisosynovectomy (RS) is a local form of radionuclide therapy used in various forms of arthritis characterized by synovitis. In hemophilic arthropathy, RS provides removal of inflamed synovium and prevents further joint damage. This review focuses on the practical aspects of radionuclide synovectomy in hemophilic patients and describes the issues both related to the methodology and post-therapeutic follow-up.

Conflict of interest:None declared.

A technical complication of radiosynovectomy in the ankle: leakage to distal tibiofibular syndesmosis

Chronic hemophilic synovitis due to intra-articular bleeding in hemophilia A (a congenital coagulation defect) is a common manifestation. Radiosynovectomy is used for the ablation of chronic hemophilic synovitis. Complications due to radiosynovectomy may be seen, such as leakage of radioactivity to the lymph nodes, liver, and spleen via the lymphatic system. We report herein 2 cases that developed leakage to the distal tibiofibular syndesmosis, lymph nodes, liver, and spleen after radiosynovectomy to the ankles. In order to prevent leakage, low-volume injection is recommended.

Opinions on radiosynovectomy for chronic haemophilic synovitis: point/counterpoint

Joint bleeding is the hallmark of severe haemophilia and the major cause of disability in patients with this coagulopathy. Repeated bleeding into the same joint can lead to chronic synovitis and progressive arthropathy. Radiosynovectomy is one option for the treatment of chronic haemophilic synovitis, but concerns about the risks of exposure to ionizing radiation have divided clinicians as to the safety and appropriate use of the procedure. This article presents two differing viewpoints, one from a pair of orthopaedic surgeons who collectively have performed more than 300 radiosynovectomies in patients with haemophilia. They maintain that radiosynovectomy is a simple, effective, safe and low-cost technique children and adults with chronic haemophilic synovitis. The other perspective is from an experienced haemophilia treater who directs a major US haemophilia treatment centre. She believes that unresolved questions about the safety of radiation exposure in children argue against the use of radiosynovectomy in paediatric patients with haemophilia.

Micronucleus evaluation for determining the chromosomal breakages after radionuclide synovectomy in patients with hemophilia

OBJECTIVE

To investigate the genotoxic effects of (90)Y and (186)Re in patients with hemophilia who were undergoing radionuclide synovectomy (RS) procedure in the last 3 years.

METHODS

Nineteen patients were enrolled in the study. Most of the patients (n = 17) were hemophilia-A (mean age 20.6 ± 10.5 years) and 18 patients (mean age 22.6 ± 10.6 years) with hemophilia who were not exposed to RS procedure were included in the study as control group. Most cases in the control group (n = 13) were hemophilia-A. (90)Y for knee joints and (186)Re for elbow or ankle joints were used to perform RS in hemophilic patients. We studied the micronucleus (MN) test on peripheral blood lymphocytes as an indicator of radiation-induced cytogenetic damage and calculated nuclear division index.

RESULTS

There was no significant difference between the patients with and without RS with respect to MN values. However, both values obtained in RS-exposed patients and control group were much elevated than values reported in literature from healthy controls. The mean MN values of patients below 20 years old were much lower but not significant than those above 20 years old. MN frequencies between (186)Re and (90)Y groups were also analyzed, and no significant difference was observed. Hemophilia patients who were treated with (186)Re showed higher levels of MN compared to patients treated with (90)Y although the difference was not significant.

CONCLUSIONS

Radioisotope synovectomy (RS) seems to be a safe procedure not causing a significant genotoxic effect on hemophilic patients, however, further studies including larger series of patients are needed to better understand the effects of RS on patients' health.

Efficacy of radiosynovectomy in rheumatoid arthritis

In this retrospective study, we evaluated the effect of radiosynovectomy of patients with rheumatoid arthritis. Radiosynovectomy was performed in 577 joints of 137 rheumatoid patients. We applied 185 MBq yttrium-90 in knees (n = 58), 74-111 MBq rhenium-186 colloids in ankle (n = 50), wrists (n = 43) and shoulders (n = 35), and 15 to 37 MBq in finger (n = 298) and toe joints (n = 46). The effect of radiosynovectomy was scored in 4 subjective categories: excellent response (no symptoms); good response (significant reduction of symptoms); moderate response (slight decrease); and bad response (no change or worsening), of pain and/or swelling in treated joint 3 months after the procedure. Excellent or good response was observed in 57% of treated knees, 63% of shoulders, 60% of wrists, 64% of ankles, 54% of thumb bases, 55% of MCP's, 54% of PIP's, 53% of DIP's, and 54% of MTP's. Side effects associated to the RSO, i.e., swelling or transient increase of pain, were recorded in 7% of the patients that resolved within 1 month. No patient had any non-reversible skin alteration after treatment, only slight erythema was observed in 5 patients. Radiosynovectomy is effective and safe in the treatment of rheumatoid arthritis.

Long-term evaluation of chromosomal breakages after radioisotope synovectomy for treatment of target joints in patients with haemophilia

Radioisotope synovectomy (RS) is defined as the intra-articular injection of radioisotopic agents with the aim of fibrosis on hypertrophic synovium in the target joint. The aim of this study was to investigate genotoxic effects on lymphocytes and malign transformation induced by Yttrium(90) (Y(90)) and Rhenium(186) (Re(186)) in children with haemophilia undergone RS. Forty haemophilia patients were enrolled. The mean age was 16.4 +/- 6.2 years (range: 8-40). Y(90) was used for knees, Re(186) was used for other joints. For safety, cytogenetic analysis was performed to determine potential chromosomal changes after RS procedure at three different time points as prior to procedure, 3rd day and 90th day. For the stimulation of chromosomal breakages, diepoxybutane was used (DEB test). Chromosomal breakages (CBs) were found in 23 patients (67.6%) prior to RS. We have found CBs additionally in nine of 11 patients who had no CBs prior to RS after 3 days of radioisotope exposure. At that time, the patients who had CBs were 29 (85.2%). At day 90, only 21 patients revealed (61.7%) CBs. The mean frequency of CBs slightly but not significantly increased in the 3rd day. However, there was a significant decreasing trend between 3rd and 90th days. Radioisotope synovectomy with Y(90) and Re(186) does not seem to induce the genotoxic effects significantly on peripheral blood lymphocytes. However, CBs even after one year in the re-evaluation of four patients, significant decrease in the number of CBs between the 3rd and 90th days and de novo CBs after exposure may be accepted as warning signals for young population. It should also be pointed out that families and patients be informed properly related with historical and potential dangers of radioisotopic agents.