Radiotherapy for non-malignant disorders: state of the art and update of the evidence-based practice guidelines

A Novel Activatable Nanoradiosensitizer for Second Near-Infrared Fluorescence Imaging-Guided Safe-Dose Synergetic Chemo-Radiotherapy of Rheumatoid Arthritis

The precise theranostics of rheumatoid arthritis (RA) remains a formidable challenge in clinical practice. Exploring novel applications of contemporary therapeutic approaches like chemo-radiotherapy is promising as a highly effective strategy for RA. Herein, a novel activatable nanoradiosensitizer-40 (denoted as IRnR-40) is developed, based on encapsulating the clinically approved drugs cisplatin (DDP) and indocyanine green (ICG) within a gelatin shell to achieve second near-infrared fluorescence (NIR-II FL) imaging-guided safe-dose synergetic chemo-radiotherapy. The high concentration of matrix metalloproteinase-9 (MMP-9) in the RA microenvironment plays a pivotal role in triggering the responsive degradation of IRnR-40, leading to the rapid release of functional molecules DDP and ICG. The released ICG serves the dual purpose of illuminating the inflamed joints to facilitate accurate target volume delineation for guiding radiotherapy, as well as acting as a real-time reporter for quantifying the release of DDP to monitor efficacy. Meanwhile, the released DDP achieves highly effective synergistic chemotherapy and radiosensitization for RA via the dual reactive oxygen species (ROS)-mediated mitochondrial apoptotic pathway. To sum up, this activatable nanoradiosensitizer IRnR-40 is believed to be the first attempt to achieve efficient NIR-II FL imaging-guided safe-dose chemo-radiotherapy for RA, which provides a new paradigm for precise theranostics of refractory benign diseases.

Preventive and therapeutic effects of low-dose whole-body irradiation on collagen-induced rheumatoid arthritis in mice

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by progressive joint inflammation, resulting in cartilage destruction and bone erosion. It was reported that low-dose radiation modulates immune disease. Here, we investigated whether low-dose whole-body irradiation has preventive and therapeutic effects in collagen-induced RA (CIA) mouse models. Fractionated low-dose irradiation (0.05 Gy/fraction, total doses of 0.1, 0.5 or 0.8 Gy) was administered either concurrently with CIA induction by Type II collagen immunization (preventive) or after CIA development (therapeutic). The severity of CIA was monitored using two clinical parameters, paw swelling and redness. We also measured total Immunoglobulin G (IgG) and inflammatory cytokines (interleukine (IL)-6, IL-1β and tumor necrosis factor-alpha (TNF-α)) in the serum by enzyme-linked immunosorbent assay, and we evaluated histological changes in the ankle joints by immunohistochemistry and hematoxylin and eosin staining. Low-dose irradiation reduced CIA clinical scores by up to 41% in the preventive model and by 28% in the therapeutic model, while irradiation in the preventive model reduced the typical CIA incidence rate from 82 to 56%. In addition, low-dose irradiation in the preventive model decreased total IgG by up to 23% and decreased IL-1β and TNF-α by 69 and 67%, and in the therapeutic model, decreased total IgG by up to 35% and decreased IL-1β and IL-6 by 59 and 42% with statistical significance (P < 0.01, 0.05 and 0.001). Our findings demonstrate that low-dose radiation has preventive and therapeutic anti-inflammatory effects against CIA by controlling the immune response, suggesting that low-dose radiation may represent an alternative therapy for RA, a chronic degenerative immune disease.

Radiotherapy for benign diseases in Turkey: a patterns of care survey of the Turkish Society for Radiation Oncology (TROD 05-002)

PURPOSE

We aimed to investigate the patterns of radiotherapy (RT) care in cases of benign diseases in Turkey.

METHODS

A questionnaire survey was sent to all radiation oncology (RO) departments in Turkey. The number of patients treated for benign disease between 2015 and 2020 was requested. A list of benign conditions was given, and information on the number of patients per disease, single and total doses prescribed, weekly fractions, radiation type, energy, and device was requested.

RESULTS

Of the 138 RO departments, 29 (21%) responded. The data received concerned 15 (52%) university, 10 (34%) public, and four (14%) private hospitals. A total of 130,846 patients were treated with RT in these departments. Of these patients, 6346 (4.85%) were treated for benign conditions. The most common benign diseases treated with RT were meningioma (35%), plantar fasciitis (19%), schwannoma (16%), arteriovenous malformation (11%), and pituitary adenoma (7%). Most centers performed RT for paraganglioma, heterotopic ossification, vertebral hemangioma, and Graves' ophthalmopathy, but none treated arthrosis. Wide variations were observed across the departments. Radiosurgery for intracranial pathologies was performed intensively in four centers. By contrast, RT for plantar fasciitis was predominantly treated in five centers, one of which had more than 1000 patients.

CONCLUSION

The ratio of patients who underwent RT for benign diseases in Turkey among all patients who underwent RT was 4.85%. The common pattern of RT in 72% of patients was radiosurgery for intracranial benign diseases, followed by low-dose RT for plantar fasciitis in 19%.

Osteo-immunological impact of radon spa treatment: due to radon or spa alone? Results from the prospective, thermal bath placebo-controlled RAD-ON02 trial

Musculoskeletal disorders (MSDs) are associated with pain and lead to reduced mobility and quality of life for patients. Radon therapy is used as alternative or complementary to pharmaceutical treatments. According to previous reports, radon spa leads to analgesic and anti-inflammatory effects, but the cellular and molecular mechanisms are widely unknown. A previous study (RAD-ON01) revealed, that bone erosion markers like collagen fragments (C-terminal telopeptide, CTX) are reduced after radon spa treatment in serum of patients with degenerative MSDs. Within the scope of the prospective, placebo-controlled RAD-ON02 trial presented here, we analyzed the influence of radon and thermal spa treatment on osteoclastogenesis. From patient blood, we isolate monocytes, seeded them on bone slices and differentiated them in the presence of growth factors into mature osteoclasts (mOCs). Subsequent analysis showed a smaller fraction of mOCs after both treatments, which was even smaller after radon spa treatment. A significantly reduced resorbed area on bone slices reflects this result. Only after radon spa treatment, we detected in the serum of patients a significant decrease of receptor activator of NF-κB ligand (RANKL), which indicates reduced differentiation of OCs. However, other markers for bone resorption (CTX) and bone formation (OPG, OCN) were not altered after both treatments. Adipokines, such as visfatin and leptin that play a role in some MSD-types by affecting osteoclastogenesis, were not changed after both treatments. Further, also immune cells have an influence on osteoclastogenesis, by inhibiting and promoting terminal differentiation and activation of OCs, respectively. After radon treatment, the fraction of Treg cells was significantly increased, whereas Th17 cells were not altered. Overall, we observed that both treatments had an influence on osteoclastogenesis and bone resorption. Moreover, radon spa treatment affected the Treg cell population as well as the Th17/Treg ratio were affected, pointing toward a contribution of the immune system after radon spa. These data obtained from patients enrolled in the RAD-ON02 trial indicate that radon is not alone responsible for the effects on bone metabolism, even though they are more pronounced after radon compared to thermal spa treatment.

Radiotherapy for non-cancer diseases: benefits and long-term risks

PURPOSE

The discovery of X-rays was followed by a variety of attempts to treat infectious diseases and various other non-cancer diseases with ionizing radiation, in addition to cancer. There has been a recent resurgence of interest in the use of such radiotherapy for non-cancer diseases. Non-cancer diseases for which use of radiotherapy has currently been proposed include refractory ventricular tachycardia, neurodegenerative diseases (e.g. Alzheimer's disease and dementia), and Coronavirus Disease 2019 (COVID-19) pneumonia, all with ongoing clinical studies that deliver radiation doses of 0.5-25 Gy in a single fraction or in multiple daily fractions. In addition to such non-cancer effects, historical indications predominantly used in some countries (e.g. Germany) include osteoarthritis and degenerative diseases of the bones and joints. This narrative review gives an overview of the biological rationale and ongoing preclinical and clinical studies for radiotherapy proposed for various non-cancer diseases, discusses the plausibility of the proposed biological rationale, and considers the long-term radiation risks of cancer and non-cancer diseases.

CONCLUSIONS

A growing body of evidence has suggested that radiation represents a double-edged sword, not only for cancer, but also for non-cancer diseases. At present, clinical evidence has shown some beneficial effects of radiotherapy for ventricular tachycardia, but there is little or no such evidence of radiotherapy for other newly proposed non-cancer diseases (e.g. Alzheimer's disease, COVID-19 pneumonia). Patients with ventricular tachycardia and COVID-19 pneumonia have thus far been treated with radiotherapy when they are an urgent life threat with no efficient alternative treatment, but some survivors may encounter a paradoxical situation where patients were rescued by radiotherapy but then get harmed by radiotherapy. Further studies are needed to justify the clinical use of radiotherapy for non-cancer diseases, and optimize dose to diseased tissue while minimizing dose to healthy tissue.

Laser Combined with Radiotherapy for Keloid Treatment: A Novel and Efficient Comprehensive Therapy with a Lower Recurrence Rate

BACKGROUND

Keloids are a fibroproliferative skin disorder with a high recurrence rate. Combined therapies are often used in clinical treatment, but, in addition to the relatively high risk of relapse and complexity of the treatment process, side effects remain unknown for combination therapies.

METHODS

A total of 99 patients with keloids in 131 positions were included in this retrospective study. Fractional CO 2 laser therapy was first applied with energy ranging from 360 to 1008 mJ; then, 6-Mev, 900-cGy electron beam irradiation was applied twice. The first pass was initiated within 24 hours after the laser therapy, and the second pass was performed on the seventh day after laser therapy. The Patient and Observer Scar Scale evaluated the lesions before the treatment and at 6, 12, and 18 months after treatment. At each follow-up visit, the patients filled out a questionnaire on recurrence, side effects, and satisfaction.

RESULTS

The authors found a significant decrease in total Patient and Observer Scar Scale score [29 (23, 39) versus 61.2 ± 13.4; P < 0.001] at the 18-month follow-up compared with the baseline value (before the therapy). A total of 12.1% of the patients had recurrences during the 18-month follow-up period (11.1% partial recurrence and 1.0% complete recurrence). The total satisfaction rate was 97.0%. No severe adverse effects were observed during the follow-up period.

CONCLUSIONS

Laser combined with radiotherapy is a new comprehensive therapy comprising ablative lasers and radiotherapy for keloids. It had excellent clinical efficacy, low recurrence rate, and no serious adverse effects.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Nicaraven Exerts a Limited Effect on Radiation-Induced Inhibition of Tumor Growth in a Subcutaneous Murine Tumor Model

Nicaraven selectively protects normal tissue from radiation-induced injury. To further develop the clinical application of nicaraven for mitigating the side effects of cancer radiotherapy, we investigated the potential effect of nicaraven administration in radiation-induced inhibition of tumor growth. A subcutaneous tumor model was established in mice by the injection of Lewis lung cancer cells at the back of the chest. X-ray radiation was delivered to the thoracic area and different doses of nicaraven (0, 20, 50, 100 mg/kg) were administrated intraperitoneally pre- or post-irradiation. The tumor size was measured every other day. Mice were euthanized on day 30, and the tumor weight and the levels of cytokines in tumor tissue were measured. Pre- or post-irradiation administration of nicaraven up to a dose of 100 mg/kg did not significantly diminish the radiation-induced inhibition of tumor growth, but post-irradiation administration of 20 and 50 mg/kg nicaraven resulted in relatively lower tumor weight. The levels of IL-1β, IL-6, IL-10, MCP-1, MIP-2a, TGF-β1, VEGF, p53, p21, cyclin D1 and caspase-3 in tumor tissue did not change by nicaraven administration and were not significantly associated with the tumor weights. According to our experimental data, nicaraven will not significantly diminish the radiation-induced inhibition of tumor growth, even with pre-irradiation administration at a high dose.

Therapeutic and prophylactic effects of radiation therapy in the management of recurrent granulation tissue induced tracheal stenosis: a review on the role of Endobronchial brachytherapy and external beam radiation therapy

PURPOSE

Granulation tissue-induced tracheal stenosis (mainly secondary to intubation or lung transplantation) is one of the most common etiologies of benign airway obstructions. Recurrence rates after standard treatment options (surgical resection and/or endobronchial interventions) can inadvertently worsen the stricture through the stimulation of more granulation tissue generation (via increased fibroblast activity and roliferation). Low-dose radiotherapy could be a promising tool to prevent granulation tissue formation after surgery and/or endobronchial interventions regarding its established role in the treatment of keloids or hypertrophic scars, two benign diseases with similar a pathophysiology to tracheal stenosis. This study reviews case reports and small series that used endobronchial brachytherapy (EBBT) or external beam radiotherapy (EBRT) for the management of refractory granulation tissue-induced tracheal stenosis after surgery and/or endobronchial interventions.

METHODS AND MATERIALS

Case reports and series (published up to October 2022) that reported outcomes of patients with recurrent granulation tissue-induced tracheal stenosis (after surgery and/or endobronchial interventions) treated by EBBT or EBRT (in definitive or prophylactic settings) were eligible.

RESULTS

Sixteen studies (EBBT: nine studies including 69 patients, EBRT: seven studies including 32 patients) were reviewed. The pooled success rate across all studies was 74% and 97% for EBBT and EBRT, respectively.

CONCLUSIONS

Radiation therapy appears to be effective in the management of selected patients with recurrent/refractory tracheal stenosis. Response to this treatment is usually good, but further studies with a larger number of patients and long-term followup are necessary to determine the optimal technique, dose, and timing of radiation therapy, late complications, the durability of response, and criteria for patient selection.

Low-Dose Radiation Therapy (LDRT) against Cancer and Inflammatory or Degenerative Diseases: Three Parallel Stories with a Common Molecular Mechanism Involving the Nucleoshuttling of the ATM Protein?

Very early after their discovery, X-rays were used in multiple medical applications, such as treatments against cancer, inflammation and pain. Because of technological constraints, such applications involved X-ray doses lower than 1 Gy per session. Progressively, notably in oncology, the dose per session increased. However, the approach of delivering less than 1 Gy per session, now called low-dose radiation therapy (LDRT), was preserved and is still applied in very specific cases. More recently, LDRT has also been applied in some trials to protect against lung inflammation after COVID-19 infection or to treat degenerative syndromes such as Alzheimer's disease. LDRT illustrates well the discontinuity of the dose-response curve and the counterintuitive observation that a low dose may produce a biological effect higher than a certain higher dose. Even if further investigations are needed to document and optimize LDRT, the apparent paradox of some radiobiological effects specific to low dose may be explained by the same mechanistic model based on the radiation-induced nucleoshuttling of the ATM kinase, a protein involved in various stress response pathways.

The immunomodulatory properties of low-level ionizing radiation as a potential treatment for COVID-19's life-threatening symptoms

Public health experts are looking into the current coronavirus outbreak to see if there are any ways to prevent potentially fatal symptoms. Low-Dose Radiotherapy (LD-RT) induces anti-inflammatory cytokine responses that act as a counterweight to pro-inflammatory cytokines, potentially providing therapeutic benefits for COVID-19-related diseases associated with significant morbidity and mortality. This study will look into positive immuno-radiological reactions to see if they are feasible, practicable, and effective in lowering the critical inflammatory condition of the crucial stage COVID-19. This study aims to investigate the use of low-dose lung radiation in bacterial and viral pneumonia, as well as to provide a treatment plan for COVID-19-associated pneumonia. This article discusses the evidence for and against LD-RT theories in COVID-19 patients. The use of LD-RT at various stages of COVID-19 appears to be beneficial, with fewer side effects than other currently being studied treatments.

The 5Rs dilemma of radiotherapy for non-malignant diseases: 5Rs to darken OR 5Rs to shine

Many benign diseases, so called because they are not a direct cause of death, nevertheless cause significant damage to the health of patients due to the associated pain, reduced functionality, increased disability and the negative impact they have on quality of life, which, together with the limited efficacy of many of the available treatments, make their management a challenge for every specialist. Radiotherapy, which has demonstrated its efficacy not only against cancer but also in many non-tumorous diseases, appears as a therapeutic option that deserves to be taken into account. However, there is still much resistance to considering the use of radiotherapy as a valid and acceptable alternative. The 5Rs to darken summarize the doubts and contradictions many specialists face to accept radiotherapy in non-neoplastic diseases. However, other 5Rs (to shine) can be argued to claim for the safety, reliability, and usefulness of radiation treatment for benign disease and as radiotherapy specialists we have to help the evidence shine and the darkness disappear.

Non-Oncological Radiotherapy: A Review of Modern Approaches

Despite being usually delivered in oncological patients, radiotherapy can be used as a successful treatment for several non-malignant disorders. Even though this use of radiotherapy has been scarcely investigated since the 1950s, more recent interest has actually shed the light on this approach. Thus, the aim of this narrative review is to analyze the applications of non-oncological radiotherapy in different disorders. Key references were derived from a PubMed query. Hand searching and clinicaltrials.gov were also used. This review contains a narrative report and a critical discussion of non-oncological radiotherapy approaches. In conclusion, non-oncological radiotherapy is a safe and efficacious approach to treat several disorders that needs to be further investigated and used in clinical practice.

The Role of Ionizing Radiation for Diagnosis and Treatment against COVID-19: Evidence and Considerations

The Coronavirus disease 2019 (COVID-19) pandemic continues to spread worldwide with over 260 million people infected and more than 5 million deaths, numbers that are escalating on a daily basis. Frontline health workers and scientists diligently fight to alleviate life-threatening symptoms and control the spread of the disease. There is an urgent need for better triage of patients, especially in third world countries, in order to decrease the pressure induced on healthcare facilities. In the struggle to treat life-threatening COVID-19 pneumonia, scientists have debated the clinical use of ionizing radiation (IR). The historical literature dating back to the 1940s contains many reports of successful treatment of pneumonia with IR. In this work, we critically review the literature for the use of IR for both diagnostic and treatment purposes. We identify details including the computed tomography (CT) scanning considerations, the radiobiological basis of IR anti-inflammatory effects, the supportive evidence for low dose radiation therapy (LDRT), and the risks of radiation-induced cancer and cardiac disease associated with LDRT. In this paper, we address concerns regarding the effective management of COVID-19 patients and potential avenues that could provide empirical evidence for the fight against the disease.

Mental Well-Being Of Patients With Stages 0-2 Of Knee Osteoarthritis After Orthovoltage Radiotherapy: Open Randomized Trial Evaluating Quality Of Life

Objective — To compare the mental component of the quality of life (QOL) in patients with stages 0-2 of knee osteoarthritis (OA) sensu Kellgren-Lawrence after treatment either with symptomatic slow-acting drugs for osteoarthritis (SYSADOA) and non-steroidal anti-inflammatory drugs (NSAIDs), or with SYSADOA, NSAIDs and orthovoltage radiotherapy (OVRT), in an open randomized study, using the SF-36 questionnaire. Material and Methods — The patients were randomly assigned to two groups: SYSADOA and SYSADOA+OVRT. Patients were asked to fill out the SF-36 questionnaire. The results were presented in the form of a mean of scores on each of four QOL survey sections for both groups at five time points: before and immediately after the treatment, at 6 months, 12 months and 36 months. Results — The groups were similar in their baselines characteristics (age, gender, body mass index [BMI], pain syndrome duration). Being initially equal, QOL improved by the end of treatment in both groups with statistically significantly greater improvement after OVRT. Further on, the QOL indicators in the OVRT group kept increasing, peaking at 12 months for social role functioning (SRF), emotional role functioning (ERF) and vitality (V), and at 36 months for mental health (MH). In contrast, the patients of SYSADOA/NSAIDs group were experiencing a decrease in their mental component over the analyzed period of time, and the levels of three out of four indicators at 36 months were even lower than their initial values. Conclusion — Adding OVRT to the standard SYSADOA/NSAIDs treatment for knee OA of stages 0-2 ensured improved mental well-being of patients for at least three years.

ROS- and Radiation Source-Dependent Modulation of Leukocyte Adhesion to Primary Microvascular Endothelial Cells

Anti-inflammatory effects of low-dose irradiation often follow a non-linear dose–effect relationship. These characteristics were also described for the modulation of leukocyte adhesion to endothelial cells. Previous results further revealed a contribution of reactive oxygen species (ROS) and anti-oxidative factors to a reduced leukocyte adhesion. Here, we evaluated the expression of anti-oxidative enzymes and the transcription factor Nrf2 (Nuclear factor-erythroid-2-related factor 2), intracellular ROS content, and leukocyte adhesion in primary human microvascular endothelial cells (HMVEC) upon low-dose irradiation under physiological laminar shear stress or static conditions after irradiation with X-ray or Carbon (C)-ions (0–2 Gy). Laminar conditions contributed to increased mRNA expression of anti-oxidative factors and reduced ROS in HMVEC following a 0.1 Gy X-ray and 0.5 Gy C-ion exposure, corresponding to reduced leukocyte adhesion and expression of adhesion molecules. By contrast, mRNA expression of anti-oxidative markers and adhesion molecules, ROS, and leukocyte adhesion were not altered by irradiation under static conditions. In conclusion, irradiation of endothelial cells with low doses under physiological laminar conditions modulates the mRNA expression of key factors of the anti-oxidative system, the intracellular ROS contents of which contribute at least in part to leucocyte adhesion, dependent on the radiation source.

Analgesic effects of low-dose radiotherapy in greater trochanteric pain syndrome: results in a clinical series of 155 patients with recurrent or refractory symptoms

PURPOSE

This prospective study assessed the effects of low-dose radiotherapy in patients diagnosed with greater trochanteric pain syndrome (GTPS) with recurrent symptoms or refractory to previous conservative measures.

METHODS

We evaluated a total of 155 patients (90.3% women, mean age 69 years). Most patients (n = 136) received 10 Gy (1 Gy/day/3 fractions per week on alternate days), but after recommendations of DEGRO guidelines published in 2015, the remaining 19 patients (12.2%) received 6 Gy (1 Gy/day/3 fractions per week on alternate days).

RESULTS

At the pre-treatment visit, the mean (standard deviation, SD) visual analog scale (VAS) score was 8), which decreased to 5 (SD 2.2) after 1 month of the end of treatment and to 4 (SD 2.3) after 4 months. An objective symptom response with increased mobility, better sleep quality, and reduction of analgesic medication was found in 56% of patients at 1 month. In 129 patients (83.2%), there was a decrease of at least 1 point in the VAS score, and in 49 patients (29.0%), the VAS score was lower than 3. The mean length of follow-up was 45 months. The probability of maintaining the analgesic response estimated by the Kaplan-Meier method was 53% at 5 years.

CONCLUSION

Low dose radiotherapy effectively improved pain in the trochanteric area in most patients with recurrent or refractory GTPS, allowing a reduction in the need for analgesic medications and, more, importantly, better functioning and mobility. Further randomized studies in selected populations of GTPS are needed to define the treatment position of low-dose radiotherapy in this clinical setting.

What Would Become of Nuclear Risk if Governments Changed Their Regulations to Recognize the Evidence of Radiation's Beneficial Health Effects for Exposures That Are Below the Thresholds for Detrimental Effects?

The 1953 Atoms for Peace Speech to the United Nations proposed applying nuclear energy to essential needs, including abundant electrical energy. The widespread fear of ionizing radiation from nuclear facilities and medical procedures began after the United States National Academy of Sciences performed a study of radiation dangers to the human genome. This study, initiated and managed by an oil industry benefactor, recommended in 1956 that the risk of radiation-induced mutations be assessed using the linear no-threshold dose-response model instead of the threshold model. It was followed by a study that wrongly linked low radiation to cancer among the atomic bomb survivors. The ensuing controversy resulted in a compromise. The National Committee on Radiation Protection adopted the precautionary principle policy in 1959, justified by fear of cancer and lack of knowledge. The United States and all other countries followed this recommendation, which remains unchanged 62 years later. Its impact on nuclear energy and medicine has been profound. Many costly regulations have been enacted to prevent very unlikely human or equipment failures-failures that would lead to radiation exposures that are below the dose thresholds for lasting harmful effects. Potential low-dose radiation therapies, against inflammation, cancer, autoimmune, and neurodegenerative diseases, are shunned.

Low-dose radiation therapy for hand osteoarthritis: shaking hands again?

BACKGROUND

Hand osteoarthritis (HOA) is one of the most common causes of pain and functional disability in western countries and there is still no definitive cure. Low-dose radiation therapy (LDRT) has anti-inflammatory properties that have shown to be effective in the symptomatic relief of various degenerative musculoskeletal disorders. We designed a clinical protocol using LDRT for symptomatic HOA and present results and tolerance in the first 100 patients included.

MATERIALS AND METHODS

Between April 2015 and March 2021, 100 patients with a median age of 60 were treated. Fifty-seven patients suffering from proximal/distal interphalangeal joint pain, 40 patients with thumb arthritis, 2 patients with radiocarpal joint affection and 1 patient with metacarpophalangeal joint pain were enrolled. LDRT comprised of 6 fractions of 0.5-1 Gy on every other day up to a total dose of 3-6 Gy. Clinical response was evaluated according to the visual analog scale (VAS) for pain level and the von Pannewitz score (VPS) for joint functionality. Any patients not achieving subjective adequate pain relief after 8 weeks of treatment were offered a second identical LDRT course.

RESULTS

With a median follow-up of 10.5 months (range 7.55-12.45), 94% reported an improvement in the pain, with a significant reduction in the VAS level after 3, 6 and 12 months (p < 0.001). Sixty-three patients needed a second course of treatment at a median time interval of 12 weeks (range 9-14). The mean VAS score before treatment was 8 (range 3-10). After treatment, it was 5 (range 1-10). After 3, 6 and 12 months, the mean VAS scores were 4 (range 0-9), 3 (range 0-9) and 3.5 (range 0-9), respectively. Seventy patients reported functionality improvements after LDRT according to the von Pannewitz score. No acute or late complications were observed.

CONCLUSION

LDRT appears to be safe and useful for HOA and is associated with good rates of pain relief and functionality improvements. However, further studies are necessary to confirm these promising results.

Radiotherapy CT-based contouring atlas for non-malignant skeletal and soft tissue disorders: a practical proposal from Spanish experience

OBJECTIVE

Interest in low-dose radiotherapy (LD-RT) for the symptomatic treatment of nonmalignant conditions, including inflammatory and degenerative disorders of the joints and para-articular soft tissues, has increased substantially in recent years. In the present document, we provide a CT-based contouring atlas to help identify and delineate the most common osteoarticular regions susceptible to LD-RT.

METHODS

The clinical efficacy of LD-RT is supported by a large body of evidence. However, there is no consensus on the parameters for contouring the planning target volume (PTV). Moreover, 3D simulation and planning should be the standard of care even for nonmalignant disorders. For this reason, the present guidelines were prepared to help guide PTV contouring based on CT images, with the same quality criteria for patient immobilization, treatment simulation, planning and delivery as those routinely applied for cancer radiotherapy.

RESULTS

PTV for radiotherapy requires precise identification of the target areas based on CT and other imaging techniques. Using a series of cases treated at our institution, we have defined the PTVs for each location on the simulation CT to establish the relationship between the image and the anatomical structures to be treated. We also specify the immobilization systems used to ensure treatment accuracy and reproducibility.

CONCLUSIONS

This comprehensive atlas based on CT images may be of value to radiation oncologists who wish to use LD-RT for the symptomatic treatment of degenerative or inflammatory osteoarticular diseases.

ADVANCES IN KNOWLEDGE

The recommendations and contouring atlas described in this article provide an eminently practical tool for LD-RT in non-malignant conditions, based on the same quality criteria recommended for all modern radiotherapy treatments in Spain.

Low-dose radiation therapy for osteoarthritis and enthesopathies: a review of current data

BACKGROUND

Osteoarthritis (OA), the most common degenerative joint disease, is associated with severe functional limitation and impairment of quality of life. Numerous reports have documented the clinical efficacy of low-dose radiotherapy (LD-RT) in the management of various inflammatory disorders, including OA. In this paper, we assessed the clinical literature involving the use of LD-RT in the treatment of OA, its dose-response features, possible underlying mechanistic features, and optimal therapeutic dose range.

METHODS

We carried out a systematic review based on the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements and evaluated articles meeting the inclusion criteria for this review.

RESULTS

A total of 361 articles were identified from databases, such as Scopus, PubMed, Embase, and Science Direct out of which 224 articles were duplicates and were discarded. Of the remaining 137 articles, 74 articles were un-related, 27 articles were review articles, eight were conference abstracts, three were letters, two were editorials, two were notes, and one was a book chapter. Finally, 20 articles met all the inclusion criteria and were included in this systematic review.

DISCUSSION

Several single-arm retrospective/prospective studies showed advantages for LD-RT in the management of OA in terms of pain relief, improvement of mobility and function, and showed minimal side effects. Mechanistic considerations involve positive subcellular effects mediated by the activation of a nuclear factor erythroid 2-related transcription factor (Nrf2) mediated antioxidant response. Further research on both the short- and long-term effects of LD-RT on OA and other inflammatory disorders is recommended.

Impact of the Spectral Composition of Kilovoltage X-rays on High-Z Nanoparticle-Assisted Dose Enhancement

Nanoparticles (NPs) with a high atomic number (Z) are promising radiosensitizers for cancer therapy. However, the dependence of their efficacy on irradiation conditions is still unclear. In the present work, 11 different metal and metal oxide NPs (from Cu (Z_Cu = 29) to Bi₂O₃ (Z_Bi = 83)) were studied in terms of their ability to enhance the absorbed dose in combination with 237 X-ray spectra generated at a 30–300 kVp voltage using various filtration systems and anode materials. Among the studied high-Z NP materials, gold was the absolute leader by a dose enhancement factor (DEF; up to 2.51), while HfO₂ and Ta₂O₅ were the most versatile because of the largest high-DEF region in coordinates U (voltage) and E_eff (effective energy). Several impacts of the X-ray spectral composition have been noted, as follows: (1) there are radiation sources that correspond to extremely low DEFs for all of the studied NPs, (2) NPs with a lower Z in some cases can equal or overcome by the DEF value the high-Z NPs, and (3) the change in the X-ray spectrum caused by a beam passing through the matter can significantly affect the DEF. All of these findings indicate the important role of carefully planning radiation exposure in the presence of high-Z NPs.

COVID-19-Associated Pneumonia: Radiobiological Insights

The evolution of SARS-CoV-2 pneumonia to acute respiratory distress syndrome is linked to a virus-induced “cytokine storm”, associated with systemic inflammation, coagulopathies, endothelial damage, thrombo-inflammation, immune system deregulation and disruption of angiotensin converting enzyme signaling pathways. To date, the most promising therapeutic approaches in COVID-19 pandemic are linked to the development of vaccines. However, the fight against COVID-19 pandemic in the short and mid-term cannot only rely on vaccines strategies, in particular given the growing proportion of more contagious and more lethal variants among exposed population (the English, South African and Brazilian variants). As long as collective immunity is still not acquired, some patients will have severe forms of the disease. Therapeutic perspectives also rely on the implementation of strategies for the prevention of secondary complications resulting from vascular endothelial damage and from immune system deregulation, which contributes to acute respiratory distress and potentially to long term irreversible tissue damage. While the anti-inflammatory effects of low dose irradiation have been exploited for a long time in the clinics, few recent physiopathological and experimental data suggested the possibility to modulate the inflammatory storm related to COVID-19 pulmonary infection by exposing patients to ionizing radiation at very low doses. Despite level of evidence is only preliminary, these preclinical findings open therapeutic perspectives and are discussed in this article.

Effects of Adipose-Derived Stem Cells and Platelet-Rich Plasma for Prevention of Alopecia and Other Skin Complications of Radiotherapy

BACKGROUND

Radiotherapy (RT) involves the use of ionizing radiation in treating malignancies and benign disorders. However, RT damages target and healthy surrounding tissues in a dose-dependent manner. This effectively reduces patient compliance and quality of life, thereby warranting the prevention of RT-induced adverse effects on skin. Adipose-derived stem cells (ASCs) are used to treat RT-induced damage and platelet-rich plasma (PRP) provides a scaffold that potentiates the effects of ASCs. Thus, the aim of this study was to determine the mechanism employed by ASCs and PRP in protecting against RT-induced adverse effects.

METHODS

We have established an immunodeficient mouse transplantation model using which human hair follicular units were implanted. When the follicular units were macroscopically and microscopically mature and anagenic, we administered localized RT. Subsequently, the mice were randomly divided into 4 groups based on the subcutaneous injection of the following to the irradiated transplantation site: saline, PRP, ASCs, and a combination of ASCs and PRP. Next, we used macroscopic and microscopic analyses to determine the protective effects of the injected solutions on skin and hair follicles.

RESULTS

Adipose-derived stem cells reduced RT-induced adverse effects, such as impaired wound healing, alopecia, skin atrophy, and fibrosis by suppressing inflammation, dystrophy, degeneration, connective tissue synthesis, and apoptosis and increasing cellular proliferation, differentiation, and signaling. Moreover, these effects were augmented by PRP.

CONCLUSIONS

Thus, co-administering ASCs with PRP in mice prevented RT-induced adverse effects and can be tested for use in clinical practice.

[Low dose radiotherapy for COVID-19 pneumopathy: Biological rationale and literature review]

La pandémie de coronavirus disease 2019 (covid-19) due au severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) évolue depuis un peu plus d’un an. Si la majorité des formes est bénigne, des pneumopathies graves, voire mortelles, se développent chez certains patients plus à risque. De nombreuses pistes thérapeutiques ont été explorées avec cependant trop peu d’impact sur la mortalité. C’est dans ce contexte que Kirkby et Mackenzie ont rappelé en avril 2020 les propriétés anti-inflammatoires de la radiothérapie de faible dose (délivrant moins de 1 Gy) et son utilisation dans le traitement des pneumopathies bactériennes et virales avant l’ère des antibiotiques. En effet, de larges données in vitro et in vivo ont démontré le rationnel biologique à l’origine de la diminution de l’inflammation après une radiothérapie de faible dose dans de nombreuses pathologies. Depuis un an, trois essais cliniques de phase I/II ont été publiés ainsi qu’un essai randomisé, rapportant la faisabilité et l’amélioration clinique et biologique d’un traitement bipulmonaire par une dose 0,5 à 1 Gy. Treize autres études, dont une phase III randomisée, sont en cours dans le monde. Celles-ci pourront permettre de mieux apprécier les effets de la radiothérapie de faible dose pour la pneumonie à SARS-CoV-2. Cette revue s’attache à rappeler le rationnel biologique de l’utilisation de la radiothérapie de faible dose dans les pneumopathies, et de rapporter les résultats des essais publiés ou en cours sur son utilisation spécifique pour la pneumopathie à SARS-CoV-2.

A retrospective study of hypofractionated radiotherapy for keloids in 100 cases

At present, the consensus on the best treatment for keloids is the combination of clinical and surgical therapies, if necessary, associated with adjuvant radiotherapy like brachytherapy. Whereas, the uniform scheme of radiotherapy in keloids is unclear. Here, we conducting a retrospective analysis to assess the efficacy and safety of a specific treatment regimen (20 Gy in 5 fractions) in keloid patients. We retrospectively analysed the medical records of keloid patients receiving auxiliary postoperative radiotherapy (PORT) treatment from 2009 to 2019. The patients were treated with the hypofractionation method of 20 Gy in 5 fractions. We compared the local control rate and complications, using the chi-square test and logistic regression analyses. After screening, we identified 100 keloid patients in this study, with a median follow-up of 59 months. In this study, the overall local control rate of keloid lesions was 84.8%. After multivariate analyses (primary keloid or not, family history, interval from surgery to irradiation and site), our research showed that primary keloid, site and interval from surgery to irradiation were significantly related to recurrence. Acute radiation injury and late radiation injury accounted for 3% (erythema) and 1% (skin sclerosis) of the total cases, respectively. Our results indicate that a postoperative hypofractionation with radiation dose of 20 Gy in 5 fractions may be effective, easy to accept and safe for keloid patients.

[Low-dose irradiation of non-malignant diseases: Did we throw the baby out with the bathwater?]

The irradiation of non-malignant diseases, essentially for anti-inflammatory purpose, have been largely proposed and performed worldwide until the 1970-80s. At that time, the better assessment of the radio-induced malignancies, essentially in children and young patients, as well as the efficacy of the new anti-inflammatory drugs (steroids and non-steroids), led to the almost disappearance of those techniques, at least in France. In contrast, our German colleagues are still going on treating about 50,000 patients per year for non-malignant (more or less severe) diseases. After a short historical overview, the present article suggests that we were possibly going too far in the rejection of those low-dose irradiations for benign lesions. The recent emergence of new preclinical data, the better understanding of the risk of radio-induced secondary tumours (almost nil in the elderly), and the severity of some situations, such as the cytokine storm of the COVID-19, should probably lead us to reconsider those low - and sometimes very low (less than 1Gy) - irradiations for well-selected indications in the elderly.

Low-dose radiotherapy (LD-RT) for COVID-19-induced pneumopathy: a worth considering approach

PURPOSE

It seems that 2020 would be always remembered by the name of novel coronavirus (designated as SARS-CoV-2), which exerted its deteriorating effects on the health care, economy, education, and political relationships. In August 2020 more than eight hundred thousand patients lost their lives due to acute respiratory syndrome. In the limited list of therapeutic approaches, the effectiveness of low-dose radiation therapy (LD-RT) for curing inflammatory-related diseases have sparkled a light that probably this approach would bring promising advantages for COVID-19 patients. LD-RT owns its reputation from its ability to modulate the host inflammatory responses by blocking the production of pro-inflammatory cytokines and hampering the activity of leukocytes. Moreover, the cost-effective and availability of this method allow it to be applied to a large number of patients, especially those who could not receive anti-IL-6 treatments in low-income countries. But enthusiasm for applying LD-RT for the treatment of COVID-19 patients has been muted yet.

CONCLUSION

In this review, we take a look at LD-RT mechanisms of action in the treatment of nonmalignant diseases, and then through studying both the dark and bright sides of this approach, we provide a thorough discussion if LD-RT might be a promising therapeutic approach in COVID-19 patients.

A hesitated approach: primary radiotherapy for keloids-a case series

PURPOSE

To assess the efficacy and toxicity of hypofractionated radiotherapy (RT) alone in treatment-resistant symptomatic keloids.

METHODS

Six patients with a total of 13 inoperable large keloid lesions and no response to previous treatments were admitted to our department between 2017 and 2019. All patients were examined for detailed wound localization, size, contour, and color assessment, and for objective and subjective symptoms. Response to treatment was graded as "complete remission" in case of full symptomatic relief and >75% decrease in lesion size, as "partial remission" in case of partial symptomatic relief and 25-75% decrease in lesion size, and as "stable disease" in case of no symptomatic relief or <25% decrease in lesion size. Patients were followed up monthly for the first 3 months and every 3 months thereafter by physical examination.

RESULTS

A total dose of 37.5 Gy external RT in five fractions was prescribed by 6‑MeV electrons in 4 patients and 6‑MV photons in 2 patients. Complete response was obtained in all patients at the 6‑month control. All patients were satisfied with cosmetic results at their last control. Grade 2 dermatitis developed in all patients during the second week of RT but resolved completely in all after 6 months following the end of RT.

CONCLUSION

In keloids that are unresponsive to standard treatment, hypofractionated RT using a total dose of 37.5 Gy in five fractions is feasible.

Nuclear Medicine in Times of COVID-19: How Radiopharmaceuticals Could Help to Fight the Current and Future Pandemics

The emergence and global spread of COVID-19, an infectious disease caused by the novel coronavirus SARS-CoV-2, has resulted in a continuing pandemic threat to global health. Nuclear medicine techniques can be used for functional imaging of (patho)physiological processes at the cellular or molecular level and for treatment approaches based on targeted delivery of therapeutic radionuclides. Ongoing development of radiolabeling methods has significantly improved the accessibility of radiopharmaceuticals for in vivo molecular imaging or targeted radionuclide therapy, but their use for biosafety threats such as SARS-CoV-2 is restricted by the contagious nature of these agents. Here, we highlight several potential uses of nuclear medicine in the context of SARS-CoV-2 and COVID-19, many of which could also be performed in laboratories without dedicated containment measures. In addition, we provide a broad overview of experimental or repurposed SARS-CoV-2-targeting drugs and describe how radiolabeled analogs of these compounds could facilitate antiviral drug development and translation to the clinic, reduce the incidence of late-stage failures and possibly provide the basis for radionuclide-based treatment strategies. Based on the continuing threat by emerging coronaviruses and other pathogens, it is anticipated that these applications of nuclear medicine will become a more important part of future antiviral drug development and treatment.

Low-Dose Radiation Therapy (LDRT) for COVID-19: Benefits or Risks?

The limited impact of treatments for COVID-19 has stimulated several phase 1 clinical trials of whole-lung low-dose radiation therapy (LDRT; 0.3-1.5 Gy) that are now progressing to phase 2 randomized trials worldwide. This novel but unconventional use of radiation to treat COVID-19 prompted the National Cancer Institute, National Council on Radiation Protection and Measurements and National Institute of Allergy and Infectious Diseases to convene a workshop involving a diverse group of experts in radiation oncology, radiobiology, virology, immunology, radiation protection and public health policy. The workshop was held to discuss the mechanistic underpinnings, rationale, and preclinical and emerging clinical studies, and to develop a general framework for use in clinical studies. Without refuting or endorsing LDRT as a treatment for COVID-19, the purpose of the workshop and this review is to provide guidance to clinicians and researchers who plan to conduct preclinical and clinical studies, given the limited available evidence on its safety and efficacy.

An efficient planning technique for low dose whole lung radiation therapy for covid-19 pandemic patients

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An efficient low dose whole lung RT technique developed for severe COVID-19 patients.

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Empirical MU Calculation formula fitted from actual CT images of clinical patients.

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Acceptable dose distribution verified by 3D dose calculation in real patient anatomy.

This study aimed to establish an efficient planning technique for low dose whole lung treatment that can be implemented rapidly and safely. The treatment technique developed here relied only on chest radiograph and a simple empirical monitor unit calculation formula. The 3D dose calculation in real patient anatomy, including both nonCOVID and COVID-19 patients, which took into account tissue heterogeneity showed that the dose delivered to lungs had reasonable uniformity even with this simple and quick setup.

Mining the past to treat the present, ever mindful of the future: Low-dose radiotherapy and COVID-19 pneumonia

This editorial discusses an interim analysis of the clinical trial by Hess et al. The trial examines the use of low‐dose radiotherapy in the treatment of patients with coronavirus disease 2019 (COVID‐19) pneumonia.

Efficacy of Single-Dose Radiotherapy in Preventing Posttraumatic Tendon Adhesion

Background and Aim

Posttraumatic peritendinous adhesion is the greatest obstacle to achieve normal tendon function following lacerations of extrinsic flexor tendons of the hand. In this study, we aimed to evaluate whether single-dose radiotherapy (RT) has the potential to modulate intrasynovial tendon adhesions.

Materials and Methods

A total of 80 tendons from the third to fourth flexor profundus of both hind paws of 20 adult New Zealand rabbits were used in this study. Rabbits in the RT group received 3 Gy of X-irradiation in a single fraction. Histopathological evaluation of longitudinal sections of tendons was made using the Tang grading system for peritendinous adhesions. Intratendinous quality of the healing tissue in the laceration zone was assessed using a modified Movin scale.

Results

Adhesion and inflammatory response were greater in the RT group (p˂0.001). Tendon healing in the radiation group was found to be more uniform and organized compared with the control group. However, this difference was not statistically significant. The nuclei of the tenocytes in the radiation group showed a closer resemblance to normal tendon tissue when compared with the control group (p=0.007).

Conclusions

Despite RT’s certain advantages such as extracorporeal use, anti-inflammatory effect, and homogenous tissue penetration, 3-Gy X-irradiation resulted in increased peritendinous posttraumatic adhesion, possibly due to dose imbalance. Increased roundness in the tenocyte nuclei was present in the RT group. Studies with different dosing regimens and a higher number of subjects are necessary to establish an ideal dose suppressing the synovial response without compromising tendon healing.

Prospective Evaluation of Changes in Pain Levels, Quality of Life and Functionality After Low Dose Radiotherapy for Epicondylitis, Plantar Fasciitis, and Finger Osteoarthritis

Background: The objective benefits of low dose radiotherapy (LDRT) for non-malignant joint disorders are controversial. This study evaluated changes in pain, quality of life (QoL) and function after LDRT for epicondylitis, plantar fasciitis, and finger osteoarthritis. Materials and Methods: Patients over 40 years old with epicondylitis, plantar fasciitis, and finger osteoarthritis were had pain following at least 6 months of conservative therapy. Patients received 0.5 Gy LDRT twice weekly for 4 weeks repeated once after 8 weeks in patients who failed to achieve complete pain relief. Patients assessed their pain according to the visual analog scale. Handgrip strength was measured with an isometric dynamometer and the fast self-paced walking test was used in patients with plantar fasciitis. QoL was evaluated according to the EQ-5D and HAQ-DI questionnaires. Results: Outcomes for 157 patients (204 sites) were documented at 2, 6, and 12 months after last LDRT. Pain reduction at rest (p < 0.001), during activity (p < 0.001) and increase in handgrip strength (extension p < 0.001, flexion p = 0.002) were highly significant for patients with lateral epicondylitis. Patients with medial epicondylitis reported pain relief at rest (p = 0.041) and during activity (p = 0.041) and significant increase in handgrip strength (p = 0.022). Patients with plantar fasciitis reported pain reduction at rest (p < 0.001), during activity (p < 0.001) and faster walking times (p < 0.001). A trend toward improved QoL was observed. Patients with finger osteoarthritis reported significant pain relief during activity (p < 0.001) and a gain in handgrip strength (p = 0.004), with a trend to both pain relief at rest (p = 0.056) and stronger pinch grip (p = 0.099). Conclusions: LDRT achieved significant pain relief at rest and during activity and a corresponding objective improvement in handgrip strength in patients with epicondylitis. Pain relief at rest, during activity and improvement in walking time were demonstrated in patients with plantar fasciitis. LDRT achieved pain relief during activity, and handgrip strength was improved in patients with finger osteoarthritis. No significant effect was seen on quality of life measures for these conditions. The observed benefits were maintained 12 months after LDRT for all 3 indications and we recommend this low cost, safe intervention for patients over 40 who have failed prior conservative therapy.

Radiosensitization by Gold Nanoparticles: Impact of the Size, Dose Rate, and Photon Energy

Gold nanoparticles (GNPs) emerged as promising antitumor radiosensitizers. However, the complex dependence of GNPs radiosensitization on the irradiation conditions remains unclear. In the present study, we investigated the impacts of the dose rate and photon energy on damage of the pBR322 plasmid DNA exposed to X-rays in the presence of 12 nm, 15 nm, 21 nm, and 26 nm GNPs. The greatest radiosensitization was observed for 26 nm GNPs. The sensitizer enhancement ratio (SER) 2.74 ± 0.61 was observed at 200 kVp with 2.4 mg/mL GNPs. Reduction of X-ray tube voltage to 150 and 100 kVp led to a smaller effect. We demonstrate for the first time that the change of the dose rate differentially influences on radiosensitization by GNPs of various sizes. For 12 nm, an increase in the dose rate from 0.2 to 2.1 Gy/min led to a ~1.13-fold increase in radiosensitization. No differences in the effect of 15 nm GNPs was found within the 0.85–2.1 Gy/min range. For 21 nm and 26 nm GNPs, an enhanced radiosensitization was observed along with the decreased dose rate from 2.1 to 0.2 Gy/min. Thus, GNPs are an effective tool for increasing the efficacy of orthovoltage X-ray exposure. However, careful selection of irradiation conditions is a key prerequisite for optimal radiosensitization efficacy.

Low-dose radiation therapy for COVID-19 pneumopathy: what is the evidence?

In the current dismal situation of the COVID-19 pandemic, effective management of patients with pneumonia and acute respiratory distress syndrome is of vital importance. Due to the current lack of effective pharmacological concepts, this situation has caused interest in (re)considering historical reports on the treatment of patients with low-dose radiation therapy for pneumonia. Although these historical reports are of low-level evidence per se, hampering recommendations for decision-making in the clinical setting, they indicate effectiveness in the dose range between 0.3 and 1 Gy, similar to more recent dose concepts in the treatment of acute and chronic inflammatory/degenerative benign diseases with, e.g., a single dose per fraction of 0.5 Gy. This concise review aims to critically review the evidence for low-dose radiation treatment of COVID-19 pneumopathy and discuss whether it is worth investigating in the present clinical situation.

Low-Dose radiation therapy for benign pathologies

Radiotherapy (RT) has always been a mainstay for malignant tumors therapy, but it is also used for benign pathology. The application of low or intermediate doses of RT has been widely studied. This topic was presented and discussed in the last XX GOCO (Grup Oncològic Català-Occità) meeting. The aim of this article is to review the indications of low dose irradiation (LD-RT), total dose and different fractionations, the public to whom it can be directed, and to offer an analysis about secondary effects. We believe it can be useful not only for radiation oncologists, but for other physicians to consider this option for future patients.

Immune biological rationales for the design of combined radio- and immunotherapies

Cancer immunotherapies are promising treatments for many forms of cancer. Nevertheless, the response rates to, e.g., immune checkpoint inhibitors (ICI), are still in low double-digit percentage. This calls for further therapy optimization that should take into account combination of immunotherapies with classical tumor therapies such as radiotherapy. By designing multimodal approaches, immune modulatory properties of certain radiation schemes, additional immune modulation by immunotherapy with ICI and hyperthermia, as well as patient stratification based on genetic and immune constitutions have to be considered. In this context, both the tumor and its microenvironment including cells of the innate and adaptive immune system have to be viewed in synopsis. Knowledge of immune activation and immune suppression by radiation is the basis for well-elaborated addition of certain immunotherapies. In this review, the focus is set on additional immune stimulation by hyperthermia and restoration of an immune response by ICI. The impact of radiation dose and fractionation on immune modulation in multimodal settings has to be considered, as the dynamics of the immune response and the timing between radiotherapy and immunotherapy. Another big challenge is the patient stratification that should be based on matrices of biomarkers, taking into account genetics, proteomics, radiomics, and “immunomics”. One key aim is to turn immunological “cold” tumors into “hot” tumors, and to eliminate barriers of immune-suppressed or immune-excluded tumors. Comprehensive knowledge of immune alterations induced by radiation and immunotherapy when being applied together should be utilized for patient-adapted treatment planning and testing of innovative tumor therapies within clinical trials.

Necrotizing Fasciitis: Low-Dose Radiotherapy as a Potential Adjunct Treatment

Necrotizing fasciitis (NF) is a rapidly spreading bacterial infection causing extensive tissue necrosis and destruction. Despite appropriate therapy, the disease results in significant morbidity/mortality and substantial treatment costs. Several studies published in the early 1900s demonstrated the effective use of low-dose X-ray radiotherapy (RT) for the treatment of many diverse inflammatory conditions and diseases (eg, gas gangrene, sinus infections, arthritis, tendonitis, and serious inflammatory lung conditions). The mechanism by which therapeutic RT doses produce positive patient outcomes is related at least in part to its capacity to induce tissue-based anti-inflammatory responses. This action is due to the polarization of macrophages to an anti-inflammatory or M2 phenotype via optimized low-dose RT. Low-dose RT has the potential to significantly reduce debilitating surgeries and aggressive treatments required for NF, providing a 3-prong benefit in terms of patient mortality, length of hospitalization stays, and cost of health care (both short term and long term). Low cost and easy availability of low-dose RT makes it a potentially useful option for patients of every age-group. In addition, low-dose RT may be a particularly useful option in countries treating many patients who are unable to afford surgeries, antibiotics, and hyperbaric oxygen.