Effect of amifostine in head and neck cancer patients treated with radiotherapy: a systematic review and meta-analysis based on randomized controlled trials

A new approach to prevent radiation-induced xerostomia using intraglandular injection of mitochondria-boosting agents

Radiotherapy in patients with head and neck cancer fairly leads to xerostomia, profoundly affecting their quality of life. With limited effective preventive and therapeutic methods, attention has turned to exploring alternatives. This article outlines how intraglandular injection of mitochondria-boosting agents can serve as a potential strategy to reduce salivary acinar damage. This method can contribute to the thoughtful development of study protocols or medications to reduce radiation-induced salivary glands damage.

An unmet need for pharmacology: Treatments for radiation-induced gastrointestinal mucositis

Gastrointestinal mucositis (GIM) continues to be a significant issue in the management of abdominal cancer radiation treatments and chemotherapy, causing significant patient discomfort and therapy interruption or even cessation. This review will first focus on radiotherapy induced GIM, providing an understanding of its clinical landscape. Subsequently, the aetiology of GIM will be reviewed, highlighting diverse contributing factors. The cellular and tissue damage and associated molecular responses in GIM will be summarised in the context of the underlying complex biological processes. Finally, available drugs and pharmaceutical therapies will be evaluated, underscoring their insufficiency, and highlighting the need for further research and innovation. This review will emphasize the urgent need for improved pharmacologic therapeutics for GIM, which is a key research priority in oncology.

A radiobiological perspective on radioresistance or/and radiosensitivity of head and neck squamous cell carcinoma

Background

This article aimed to compile and summarize clinically relevant literature in radiation therapy, and to discuss the potential in radioresistant and radiosensitive head and neck cancer.

Study Design

Narrative review.

Materials and methods

Google Scholar, PubMed and the Cochrane Library were retrieved using combined key words such as "radiotherapy" and "head and neck cancer". Search strings additionally queried were "radioresistant", "radiosensitive", "head and neck region", "squamous cell carcinoma", in combination with Boolean Operators 'AND' and 'OR'. Subsequently, the resulting publications were included for review of the full text.

Results

Radiotherapeutic response currently in clinical observation referred to HNSCC scoping were selected into this review. The compiled mechanisms were then detailed concerning on the clinical significance, biological characteristics, and molecular function.

Conclusions

Brachytherapy or/and external-beam radiotherapy are crucial for treating HNSCC, especially the early stage patients, but in patients with locally advanced tumors, their outcome with radiation therapy is poor due to obvious radioresistance. The curative effects mainly depend on the response of radiation therapy, so an updated review is needed to optimize further applications in HNSCC radiotherapy.

Radiopaque and X-ray-Responsive Nanomedicine for Preventive Therapy of Radiation-Induced Heart Disease

Radiation-induced heart disease (RIHD) is a common radiotherapy complication. Reducing radiation exposure and post-irradiation antioxidant therapy are promising approaches. Here, a liquid metal-based core-shell nanomedicine (LMN) composed of a gallium core and a multifunctional polymeric shell with radiopaque, X-ray shielding, and X-ray-responsive antioxidation properties for preventive therapy of RIHD is developed. The liquid metal provides radiopaque properties to enhance X-ray and computed tomography imaging and attenuate radiation to prevent primary myocardial damage. Under X-ray radiation, cleavage of the diselenide bond on the polymeric shell results in the release of LMN and controlled antioxidation. In vitro and in vivo experiments have demonstrated that LMN significantly reduces myocardial injury and impaired cardiac function, stabilizes mitochondrial function, and inhibits myocardial fibrosis. This nanomedicine with radiographic contrast, radiation shielding, and responsive features provides a new strategy for the prevention of radiation-related diseases.

WR1065 conjugated to thiol-PEG polymers as novel anticancer prodrugs: broad spectrum efficacy, synergism, and drug resistance reversal

The lack of anticancer agents that overcome innate/acquired drug resistance is the single biggest barrier to achieving a durable complete response to cancer therapy. To address this issue, a new drug family was developed for intracellular delivery of the bioactive aminothiol WR1065 by conjugating it to discrete thiol-PEG polymers: 4-star-PEG-S-S-WR1065 (4SP65) delivers four WR1065s/molecule and m-PEG6-S-S-WR1065 (1LP65) delivers one. Infrequently, WR1065 has exhibited anticancer effects when delivered via the FDA-approved cytoprotectant amifostine, which provides one WR1065/molecule extracellularly. The relative anticancer effectiveness of 4SP65, 1LP65, and amifostine was evaluated in a panel of 15 human cancer cell lines derived from seven tissues. Additional experiments assessed the capacity of 4SP65 co-treatments to potentiate the anticancer effectiveness and overcome drug resistance to cisplatin, a chemotherapeutic, or gefitinib, a tyrosine kinase inhibitor (TKI) targeting oncogenic EGFR mutations. The CyQUANT®-NF proliferation assay was used to assess cell viability after 48-h drug treatments, with the National Cancer Institute COMPARE methodology employed to characterize dose-response metrics. In normal human epithelial cells, 4SP65 or 1LP65 enhanced or inhibited cell growth but was not cytotoxic. In cancer cell lines, 4SP65 and 1LP65 induced dose-dependent cytostasis and cytolysis achieving 99% cell death at drug concentrations of 11.2 ± 1.2 µM and 126 ± 15.8 µM, respectively. Amifostine had limited cytostatic effects in 11/14 cancer cell lines and no cytolytic effects. Binary pairs of 4SP65 plus cisplatin or gefitinib increased the efficacy of each partner drug and surmounted resistance to cytolysis by cisplatin and gefitinib in relevant cancer cell lines. 4SP65 and 1LP65 were significantly more effective against TP53-mutant than TP53-wild-type cell lines, consistent with WR1065-mediated reactivation of mutant p53. Thus, 4SP65 and 1LP65 represent a unique prodrug family for innovative applications as broad-spectrum anticancer agents that target p53 and synergize with a chemotherapeutic and an EGFR-TKI to prevent or overcome drug resistance.

A novel multifunctional radioprotective strategy using P7C3 as a countermeasure against ionizing radiation-induced bone loss

Radiotherapy is a critical component of cancer care but can cause osteoporosis and pathological insufficiency fractures in surrounding and otherwise healthy bone. Presently, no effective countermeasure exists, and ionizing radiation-induced bone damage continues to be a substantial source of pain and morbidity. The purpose of this study was to investigate a small molecule aminopropyl carbazole named P7C3 as a novel radioprotective strategy. Our studies revealed that P7C3 repressed ionizing radiation (IR)-induced osteoclastic activity, inhibited adipogenesis, and promoted osteoblastogenesis and mineral deposition in vitro. We also demonstrated that rodents exposed to clinically equivalent hypofractionated levels of IR in vivo develop weakened, osteoporotic bone. However, the administration of P7C3 significantly inhibited osteoclastic activity, lipid formation and bone marrow adiposity and mitigated tissue loss such that bone maintained its area, architecture, and mechanical strength. Our findings revealed significant enhancement of cellular macromolecule metabolic processes, myeloid cell differentiation, and the proteins LRP-4, TAGLN, ILK, and Tollip, with downregulation of GDF-3, SH2B1, and CD200. These proteins are key in favoring osteoblast over adipogenic progenitor differentiation, cell matrix interactions, and shape and motility, facilitating inflammatory resolution, and suppressing osteoclastogenesis, potentially via Wnt/β-catenin signaling. A concern was whether P7C3 afforded similar protection to cancer cells. Preliminarily, and remarkably, at the same protective P7C3 dose, a significant reduction in triple-negative breast cancer and osteosarcoma cell metabolic activity was found in vitro. Together, these results indicate that P7C3 is a previously undiscovered key regulator of adipo-osteogenic progenitor lineage commitment and may serve as a novel multifunctional therapeutic strategy, leaving IR an effective clinical tool while diminishing the risk of adverse post-IR complications. Our data uncover a new approach for the prevention of radiation-induced bone damage, and further work is needed to investigate its ability to selectively drive cancer cell death.

Potential applications of drug delivery technologies against radiation enteritis

INTRODUCTION

The incidence of abdominal tumors, such as colorectal and prostate cancers, continually increases. Radiation therapy is widely applied in the clinical treatment of patients with abdominal/pelvic cancers, but it often unfortunately causes radiation enteritis (RE) involving the intestine, colon, and rectum. However, there is a lack of suitable treatment options for effective prevention and treatment of RE.

AREAS COVERED

Conventional clinical drugs for preventing and treating RE are usually applied by enemas and oral administration. Innovative gut-targeted drug delivery systems including hydrogels, microspheres, and nanoparticles are proposed to improve the prevention and curation of RE.

EXPERT OPINION

The prevention and treatment of RE have not attracted sufficient attention in the clinical practice, especially compared to the treatment of tumors, although RE takes patients great pains. Drug delivery to the pathological sites of RE is a huge challenge. The short retention and weak targeting of conventional drug delivery systems affect the therapeutic efficiency of anti-RE drugs. Novel drug delivery systems including hydrogels, microspheres, and nanoparticles can allow drugs long-term retention in the gut and targeting the inflammation sites to alleviate radiation-induced injury.

Total Skin Treatment with Helical Arc Radiotherapy

For widespread cutaneous lymphoma, such as mycosis fungoides or leukemia cutis, in patients with acute myeloid leukemia (AML) and for chronic myeloproliferative diseases, total skin irradiation is an efficient treatment modality for disease control. Total skin irradiation aims to homogeneously irradiate the skin of the entire body. However, the natural geometric shape and skin folding of the human body pose challenges to treatment. This article introduces treatment techniques and the evolution of total skin irradiation. Articles on total skin irradiation by helical tomotherapy and the advantages of total skin irradiation by helical tomotherapy are reviewed. Differences among each treatment technique and treatment advantages are compared. Adverse treatment effects and clinical care during irradiation and possible dose regimens are mentioned for future prospects of total skin irradiation.

Noninvasive Systemic Modalities for Prevention of Head and Neck Radiation-Associated Soft Tissue Injury: A Narrative Review

BACKGROUND

 Radiation-associated soft tissue injury is a potentially devastating complication for head and neck cancer patients. The damage can range from minor sequelae such as xerostomia, which requires frequent daily maintenance, to destructive degenerative processes such as osteoradionecrosis, which can contribute to flap failure and delay or reverse oral rehabilitation. Despite the need for effective radioprotectants, the literature remains sparse, primarily focused on interventions beyond the surgeon's control, such as maintenance of good oral hygiene or modulation of radiation dose.

METHODS

 This narrative review aggregates and explores noninvasive, systemic treatment modalities for prevention or amelioration of radiation-associated soft tissue injury.

RESULTS

 We highlighted nine modalities with the most clinical potential, which include amifostine, melatonin, palifermin, hyperbaric oxygen therapy, photobiomodulation, pentoxifylline-tocopherol-clodronate, pravastatin, transforming growth factor-β modulators, and deferoxamine, and reviewed the benefits and limitations of each modality. Unfortunately, none of these modalities are supported by strong evidence for prophylaxis against radiation-associated soft tissue injury.

CONCLUSION

 While we cannot endorse any of these nine modalities for immediate clinical use, they may prove fruitful areas for further investigation.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

Radioprotective effects and mechanism of HL-003 on radiation-induced salivary gland damage in mice

Ionizing radiation (IR) can cause damage to the structure and function of salivary glands. Our research group independently synthesized the ROS scavenger, HL-003. The aim of this study was to explore the protective effects and underlying mechanisms of HL-003 on radiation-induced salivary gland injury. Salivary flow rate measurement, H&E staining, immunohistochemistry, FRAP, TUNEL, and western blotting were used to evaluate the radioprotective effect on salivary glands. The results showed that HL-003 protected the salivary secretion function by protecting the AQP-5 protein, on the salivary epithelial cell membrane, from IR damage. HL-003 reduced oxidative stress in the salivary gland by regulating the expression of ROS-related proteins NOX4, SOD2, and 8-OHdG. Furthermore, HL-003 downregulated the expression of p-p53, Bax, caspase 3, and caspase 9, and upregulated the expression of Bcl-2, suggesting that it could inhibit the activation of p53 to reduce cell apoptosis. In conclusion, HL-003 is an effective radioprotector that prevents damage of the radiation-induced salivary gland.

Amifostine (WR-2721) Mitigates Cognitive Injury Induced by Heavy Ion Radiation in Male Mice and Alters Behavior and Brain Connectivity

The deep space environment contains many risks to astronauts during space missions, such as galactic cosmic rays (GCRs) comprised of naturally occurring heavy ions. Heavy ion radiation is increasingly being used in cancer therapy, including novel regimens involving carbon therapy. Previous investigations involving simulated space radiation have indicated a host of detrimental cognitive and behavioral effects. Therefore, there is an increasing need to counteract these deleterious effects of heavy ion radiation. Here, we assessed the ability of amifostine to mitigate cognitive injury induced by simulated GCRs in C57Bl/6J male and female mice. Six-month-old mice received an intraperitoneal injection of saline, 107 mg/kg, or 214 mg/kg of amifostine 1 h prior to exposure to a simplified five-ion radiation (protons, 28Si, 4He, 16O, and 56Fe) at 500 mGy or sham radiation. Mice were behaviorally tested 2-3 months later. Male mice that received saline and radiation exposure failed to show novel object recognition, which was reversed by both doses of amifostine. Conversely, female mice that received saline and radiation exposure displayed intact object recognition, but those that received amifostine prior to radiation did not. Amifostine and radiation also had distinct effects on males and females in the open field, with amifostine affecting distance moved over time in both sexes, and radiation affecting time spent in the center in females only. Whole-brain analysis of cFos immunoreactivity in male mice indicated that amifostine and radiation altered regional connectivity in areas involved in novel object recognition. These data support that amifostine has potential as a countermeasure against cognitive injury following proton and heavy ion irradiation in males.

Assessment of cellular and molecular changes in the rat brain after gamma radiation and radioprotection by anisomycin

The objective of the study was to describe cellular and molecular markers of radioprotection by anisomycin, focusing on the changes in rat brain tissue. Two-month-old Wistar rats were exposed to a 60Co radiation source at a dose of 6 Gy, with or without radioprotection with anisomycin (150 mg/kg) administered subcutaneously 30 min before or 3 or 6 h after irradiation. Survivors were analyzed 30 days after treatment. Astroglial and microglial responses were investigated based on the expression of glial markers assessed with immunohistochemistry, and quantitative changes in brain biomolecules were investigated by Raman microspectroscopy. In addition, blood plasma levels of pro-inflammatory (interleukin 6 and tumor necrosis factor α) and anti-inflammatory (interleukin 10) cytokines were assessed. We found that application of anisomycin either before or after irradiation significantly decreased the expression of the microglial marker Iba-1. We also found an increased intensity of Raman spectral bands related to nucleic acids, as well as an increased level of cytokines when anisomycin was applied after irradiation. This suggests that the radioprotective effects of anisomycin are by decreasing Iba-1 expression and stabilizing genetic material by increasing the level of nucleic acids.

Radiation exposure induces cross-species temporal metabolic changes that are mitigated in mice by amifostine

Exposure to acute, damaging radiation may occur through a variety of events from cancer therapy and industrial accidents to terrorist attacks and military actions. Our understanding of how to protect individuals and mitigate the effects of radiation injury or Acute Radiation Syndrome (ARS) is still limited. There are only a few Food and Drug Administration-approved therapies for ARS; whereas, amifostine is limited to treating low dose (0.7-6 Gy) radiation poisoning arising from cancer radiotherapy. An early intervention is critical to treat ARS, which necessitates identifying diagnostic biomarkers to quickly characterize radiation exposure. Towards this end, a multiplatform metabolomics study was performed to comprehensively characterize the temporal changes in metabolite levels from mice and non-human primate serum samples following γ-irradiation. The metabolomic signature of amifostine was also evaluated in mice as a model for radioprotection. The NMR and mass spectrometry metabolomics analysis identified 23 dysregulated pathways resulting from the radiation exposure. These metabolomic alterations exhibited distinct trajectories within glucose metabolism, phospholipid biosynthesis, and nucleotide metabolism. A return to baseline levels with amifostine treatment occurred for these pathways within a week of radiation exposure. Together, our data suggests a unique physiological change that is independent of radiation dose or species. Furthermore, a metabolic signature of radioprotection was observed through the use of amifostine prophylaxis of ARS.

Caffeic Acid Phenethyl Ester-Incorporated Radio-Sensitive Nanoparticles of Phenylboronic Acid Pinacol Ester-Conjugated Hyaluronic Acid for Application in Radioprotection

We synthesized phenylboronic acid pinacol ester (PBPE)-conjugated hyaluronic acid (HA) via thiobis(ethylamine) (TbEA) linkage (abbreviated as HAsPBPE conjugates) to fabricate the radiosensitive delivery of caffeic acid phenetyl ester (CAPE) and for application in radioprotection. PBPE was primarily conjugated with TbEA and then PBPE-TbEA conjugates were conjugated again with hyaluronic acid using carbodiimide chemistry. CAPE-incorporated nanoparticles of HAsPBPE were fabricated by the nanoprecipitation method and then the organic solvent was removed by dialysis. CAPE-incorporated HAsPBPE nanoparticles have a small particle size of about 80 or 100 nm and they have a spherical shape. When CAPE-incorporated HAsPBPE nanoparticles were irradiated, nanoparticles became swelled or disintegrated and their morphologies were changed. Furthermore, the CAPE release rate from HAsPBPE nanoparticles were increased according to the radiation dose, indicating that CAPE-incorporated HAsPBPE nanoparticles have radio-sensitivity. CAPE and CAPE-incorporated HAsPBPE nanoparticles appropriately prevented radiation-induced cell death and suppressed intracellular accumulation of reactive oxygen species (ROS). CAPE and CAPE-incorporated HAsPBPE nanoparticles efficiently improved survivability of mice from radiation-induced death and reduced apoptotic cell death. We suggest that HAsPBPE nanoparticles are promising candidates for the radio-sensitive delivery of CAPE.

RRx-001 Radioprotection: Enhancement of Survival and Hematopoietic Recovery in Gamma-Irradiated Mice

The present studies evaluate the in vivo prophylactic radioprotective effects of 1-bromoacetyl-3, 3-dinitroazetidine (RRx-001), a phase III anticancer agent that inhibits c-myc and downregulates CD-47, after total body irradiation (TBI), in lethally and sublethally irradiated CD2F1 male mice. A single dose of RRx-001 was administered by intraperitoneal (IP) injection 24 h prior to a lethal or sublethal radiation dose. When irradiated with 9.35 Gy, the dose lethal to 70% of untreated mice at 30 days (LD_70/30), only 33% of mice receiving RRx-001 (10 mg/kg) 24 h prior to total body irradiation (TBI) died by day 30, compared to 67% in vehicle-treated mice. The same pretreatment dose of RRx-001 resulted in a significant dose reduction factor of 1.07. In sublethally TBI mice, bone marrow cellularity was increased at day 14 in the RRx-001-treated mice compared to irradiated vehicle-treated animals. In addition, significantly higher numbers of lymphocytes, platelets, percent hematocrit and percent reticulocytes were observed on days 7 and/or 14 in RRx-001-treated mice. These experiments provide proof of principle that systemic administration of RRx-001 prior to TBI significantly improves overall survival and bone marrow regeneration.

Use of C. elegans as a 3R-compliant in vivo model for the chemoprevention of cisplatin-induced neurotoxicity

Anticancer therapeutics can provoke severe side effects that impair the patient's quality of life. A frequent dose-limiting side effect of platinum-based anticancer therapy is neurotoxicity. Its pathophysiology is poorly understood, and effective preventive or therapeutic measures are missing. Therefore, elucidation of the molecular mechanism of platinating drug-induced neurotoxicity and the development of preventive strategies is urgently needed. To this end, we aim to use C. elegans as a 3R-compliant in vivo model. The 3R principles were conceived for animal welfare in science concerning animal experiments, which should be replaced, reduced or refined. We can analytically demonstrate dose-dependent uptake of cisplatin (CisPt) in C. elegans, as well as genotoxic and cytotoxic effects based on DNA adduct formation (i.e., 1,2-GpG intrastrand crosslinks), induction of apoptosis, and developmental toxicity. Measuring the impairment of pharyngeal pumping as a marker of neurotoxicity, we found that especially CisPt reduces the pumping frequency at concentrations where basal and touch-provoked movement were not yet affected. CisPt causes glutathione (GSH) depletion and RNAi-mediated knockdown of the glutamate-cysteine ligase GCS-1 aggravates the CisPt-induced inhibition of pharyngeal pumping. Moreover, N-acetylcysteine (NAC) mitigated CisPt-triggered toxicity, indicating that GSH depletion contributes to the CisPt-induced pharyngeal damage. In addition to NAC, amifostine (WR1065) also protected the pharynx of C. elegans from the toxic effects of CisPt. Measuring pharyngeal activity by the electrophysiological recording of neurotransmission in the pharynx, we confirmed that CisPt is neurotoxic in C. elegans and that NAC is neuroprotective in the nematode. The data support the hypothesis that monitoring the pharyngeal activity of C. elegans is a useful surrogate marker of CisPt-induced neurotoxicity. In addition, a low GSH pool reduces the resistance of neurons to CisPt treatment, and both NAC and WR1065 are capable of attenuating platinum-induced neurotoxicity during post-incubation in C. elegans. Overall, we propose C. elegans as a 3R-compliant in vivo model to study the molecular mechanisms of platinum-induced neurotoxicity and to explore novel neuroprotective therapeutic strategies to alleviate respective side effects of platinum-based cancer therapy.

Antioxidative Stress: Inhibiting Reactive Oxygen Species Production as a Cause of Radioresistance and Chemoresistance

Radiotherapy and chemotherapy are the most effective nonsurgical treatments for cancer treatment. They usually induce regulated cell death by increasing the level of reactive oxygen species (ROS) in tumour cells. However, as intracellular ROS concentration increases, many antioxidant pathways are concurrently upregulated by cancer cells to inhibit ROS production, ultimately leading to drug resistance. Understanding the mechanism of antioxidant stress in tumour cells provides a new research direction for overcoming therapeutic resistance. In this review, we address (1) how radiotherapy and chemotherapy kill tumour cells by increasing the level of ROS, (2) the mechanism by which ROS activate antioxidant pathways and the subsequent cellular mitigation of ROS in radiotherapy and chemotherapy treatments, and (3) the potential research direction for targeted treatment to overcome therapeutic resistance.

Cyclophosphamide-Induced Inflammation of Taste Buds and Cytoprotection by Amifostine

Taste buds in the oral cavity have a complex immune system regulating normal functions and inflammatory reactions. Cyclophosphamide (CYP), a chemotherapy drug, has wide-ranging disruptive effects on the taste system including loss of taste function, taste sensory cells, and capacity for taste cell renewal. In bladder epithelium, CYP also induces inflammation. To determine if CYP induces inflammation in taste buds, we used immunohistochemistry to examine tumor necrosis factor alpha (TNF-α) (a proinflammatory cytokine) expression over a 72-hour period. Expression of TNF-α increased in a subset of PLCβ2 labeled (Type II) cells, but not SNAP-25 labeled (Type III) cells, between 8 and 24 h postinjection and declined slowly thereafter. This inflammatory response may play an important role in the disruptive effects of CYP on the taste system. Further, pretreatment with amifostine, a sulfhydryl drug known to protect normal tissues during chemo- or radiation therapy, reduced the amount of CYP-induced TNF-α expression in taste buds, suggesting this drug is capable of protecting normal cells of the taste system from adverse effects of CYP. Amifostine, used as a pretreatment to CYP and possibly other chemotherapy drugs, may offer clinical support for preventing negative side effects of chemotherapy on the taste system.

Radiation-induced neuropathies in head and neck cancer: prevention and treatment modalities

Head and neck cancer (HNC) is the sixth most common human malignancy with a global incidence of 650,000 cases per year. Radiotherapy (RT) is commonly used as an effective therapy to treat tumours as a definitive or adjuvant treatment. Despite the substantial advances in RT contouring and dosage delivery, patients suffer from various radiation-induced complications, among which are toxicities to the nervous tissues in the head and neck area. Radiation-mediated neuropathies manifest as a result of increased oxidative stress-mediated apoptosis, neuroinflammation and altered cellular function in the nervous tissues. Eventually, molecular damage results in the formation of fibrotic tissues leading to susceptible loss of function of numerous neuronal substructures. Neuropathic sequelae following irradiation in the head and neck area include sensorineural hearing loss, alterations in taste and smell functions along with brachial plexopathy, and cranial nerves palsies. Numerous management options are available to relieve radiation-associated neurotoxicities notwithstanding treatment alternatives that remain restricted with limited benefits. In the scope of this review, we discuss the use of variable management and therapeutic modalities to palliate common radiation-induced neuropathies in head and neck cancers.

A Comprehensive Review on Source, Types, Effects, Nanotechnology, Detection, and Therapeutic Management of Reactive Carbonyl Species Associated with Various Chronic Diseases

Continuous oxidation of carbohydrates, lipids, and amino acids generate extremely reactive carbonyl species (RCS). Human body comprises some important RCS namely hexanal, acrolein, 4-hydroxy-2-nonenal, methylglyoxal, malondialdehyde, isolevuglandins, and 4-oxo-2- nonenal etc. These RCS damage important cellular components including proteins, nucleic acids, and lipids, which manifests cytotoxicity, mutagenicity, multitude of adducts and crosslinks that are connected to ageing and various chronic diseases like inflammatory disease, atherosclerosis, cerebral ischemia, diabetes, cancer, neurodegenerative diseases and cardiovascular disease. The constant prevalence of RCS in living cells suggests their importance in signal transduction and gene expression. Extensive knowledge of RCS properties, metabolism and relation with metabolic diseases would assist in development of effective approach to prevent numerous chronic diseases. Treatment approaches for RCS associated diseases involve endogenous RCS metabolizers, carbonyl metabolizing enzyme inducers, and RCS scavengers. Limited bioavailability and bio efficacy of RCS sequesters suggest importance of nanoparticles and nanocarriers. Identification of RCS and screening of compounds ability to sequester RCS employ several bioassays and analytical techniques. Present review describes in-depth study of RCS sources, types, properties, identification techniques, therapeutic approaches, nanocarriers, and their role in various diseases. This study will give an idea for therapeutic development to combat the RCS associated chronic diseases.

Neurotoxicity of antineoplastic drugs: Mechanisms, susceptibility, and neuroprotective strategies

This review summarizes the adverse effects on the central and/or peripheral nervous systems that may occur in response to antineoplastic drugs. In particular, we describe the neurotoxic side effects of the most commonly used drugs, such as platinum compounds, doxorubicin, ifosfamide, 5-fluorouracil, vinca alkaloids, taxanes, methotrexate, bortezomib and thalidomide. Neurotoxicity may result from direct action of compounds on the nervous system or from metabolic alterations produced indirectly by these drugs, and either the central nervous system or the peripheral nervous system, or both, may be affected. The incidence and severity of neurotoxicity are principally related to the dose, to the duration of treatment, and to the dose intensity, though other factors, such as age, concurrent pathologies, and genetic predisposition may enhance the occurrence of side effects. To avoid or reduce the onset and severity of these neurotoxic effects, the use of neuroprotective compounds and/or strategies may be helpful, thereby enhancing the therapeutic effectiveness of antineoplastic drug.

Salivary Gland Hypofunction and Xerostomia in Head and Neck Radiation Patients

BACKGROUND

The most manifest long-term consequences of radiation therapy in the head and neck cancer patient are salivary gland hypofunction and a sensation of oral dryness (xerostomia).

METHODS

This critical review addresses the consequences of radiation injury to salivary gland tissue, the clinical management of salivary gland hypofunction and xerostomia, and current and potential strategies to prevent or reduce radiation injury to salivary gland tissue or restore the function of radiation-injured salivary gland tissue.

RESULTS

Salivary gland hypofunction and xerostomia have severe implications for oral functioning, maintenance of oral and general health, and quality of life. Significant progress has been made to spare salivary gland function chiefly due to advances in radiation techniques. Other strategies have also been developed, e.g., radioprotectors, identification and preservation/expansion of salivary stem cells by stimulation with cholinergic muscarinic agonists, and application of new lubricating or stimulatory agents, surgical transfer of submandibular glands, and acupuncture.

CONCLUSION

Many advances to manage salivary gland hypofunction and xerostomia induced by radiation therapy still only offer partial protection since they are often of short duration, lack the protective effects of saliva, or potentially have significant adverse effects. Intensity-modulated radiation therapy (IMRT), and its next step, proton therapy, have the greatest potential as a management strategy for permanently preserving salivary gland function in head and neck cancer patients.Presently, gene transfer to supplement fluid formation and stem cell transfer to increase the regenerative potential in radiation-damaged salivary glands are promising approaches for regaining function and/or regeneration of radiation-damaged salivary gland tissue.

Honey Against Radiation-induced Oral Mucositis in Head and Neck Cancer Patients. An Umbrella Review of Systematic Reviews and Meta- Analyses of the Literature

Backround: Oral mucositis (OM) consists of a major side effect of radiotherapy (RT) in head and neck (H-N) cancer patients and natural honey is gaining more and more scientific interest due to its beneficial effects in tissue repair.

OBJECTIVE

The aim of this review is to better clarify the preventive/therapeutic role of honey in the management of OM in patients with H-N cancer undergoing RT with or without chemotherapy (CT).

METHODS

We used the PubMed database to retrieve journal articles and the inclusion criteria were only reviews and meta-analyses that illustrated the effective use of honey for either the prevention or treatment of OM in H-N cancer patients receiving either RT alone or in combination with CT.

RESULTS

Our search resulted in 92 citations, of which 12 eventually fulfilled the inclusion criteria of our study. Decreased incidence and severity of OM, extended time of occurrence of mucositis, less weight loss and less treatment interruptions were occasionally documented with conventional honey use in the included reviews and meta-analyses. In contrast to conventional honey, manuka honey proved to be weak in improving OM management in the small number of included reviews in our search.

CONCLUSION

Conventional honey might constitute a highly promising natural product against OM attracting much scientific interest due to its easy accessibility and low financial cost. Hence, the lack of studies with high evidence requires further advanced research to enhance the existing knowledge about the potential value of honey in radiation-induced OM in H-N cancer patients.

Prevention and treatment of radiotherapy-induced side effects

Radiotherapy remains a mainstay of cancer treatment, being used in roughly 50% of patients. The precision with which the radiation dose can be delivered is rapidly improving. This precision allows the more accurate targeting of radiation dose to the tumor and reduces the amount of surrounding normal tissue exposed. Although this often reduces the unwanted side effects of radiotherapy, we still need to further improve patients' quality of life and to escalate radiation doses to tumors when necessary. High-precision radiotherapy forces one to choose which organ or functional organ substructures should be spared. To be able to make such choices, we urgently need to better understand the molecular and physiological mechanisms of normal tissue responses to radiotherapy. Currently, oversimplified approaches using constraints on mean doses, and irradiated volumes of normal tissues are used to plan treatments with minimized risk of radiation side effects. In this review, we discuss the responses of three different normal tissues to radiotherapy: the salivary glands, cardiopulmonary system, and brain. We show that although they may share very similar local cellular processes, they respond very differently through organ-specific, nonlocal mechanisms. We also discuss how a better knowledge of these mechanisms can be used to treat or to prevent the effects of radiotherapy on normal tissue and to optimize radiotherapy delivery.

Alterations in Tissue Metabolite Profiles with Amifostine-Prophylaxed Mice Exposed to Gamma Radiation

Acute exposure to high-dose ionizing irradiation has the potential to severely injure the hematopoietic system and its capacity to produce vital blood cells that innately serve to ward off infections and excessive bleeding. Developing a medical radiation countermeasure that can protect individuals from the damaging effects of irradiation remains a significant, unmet need and an area of great public health interest and concern. Despite significant advancements in the field of radiation countermeasure development to find a nontoxic and effective prophylactic agent for acute radiation syndrome, no such drug has yet been approved by the Food and Drug Administration. This study focuses on examining the metabolic corrections elicited by amifostine, a potent radioprotector, on tissues of vital body organs, such as the heart, spleen, and kidney. Our findings indicate that prophylaxis with this drug offers significant protection against potentially lethal radiation injury, in part, by correction of radiation-induced metabolic pathway perturbations.

The Multidisciplinary Team (MDT) Approach and Quality of Care

The core function of a multidisciplinary team (MDT) is to bring together a group of healthcare professionals from different fields in order to determine patients' treatment plan. Most of head and neck cancer (HNC) units are currently led by MDTs that at least include ENT and maxillofacial surgeons, radiation and medical oncologists. HNC often compromise relevant structures of the upper aerodigestive tract involving functions such as speech, swallowing and breathing, among others. The impairment of these functions can significantly impact patients' quality of life and psychosocial status, and highlights the crucial role of specialized nurses, dietitians, psycho-oncologists, social workers, and onco-geriatricians, among others. Hence, these professionals should be integrated in HNC MDTs. In addition, involving translational research teams should also be considered, as it will help reducing the existing gap between basic research and the daily clinical practice. The aim of this comprehensive review is to assess the role of the different supportive disciplines integrated in an MDT and how they help providing a better care to HNC patients during diagnosis, treatment and follow up.

Use of Amifostine for Cytoprotection during Radiation Therapy: A Review

BACKGROUND

Radiation therapy is a cornerstone of the therapeutic modalities used in modern oncology. However, it is sometimes limited in its ability to achieve optimal tumor control by radiation-induced normal tissue toxicity. In delivering radiation therapy, a balance must be achieved between maximizing the dose to the tumor and minimizing any injury to the normal tissues. Amifostine was the first Food and Drug Administration (FDA)-approved clinical radiation protector intended to reduce the impact of radiation on normal tissue, lessening its toxicity and potentially allowing for increased tumor dose/control. Despite being FDA-approved almost 20 years ago, Amifostine has yet to achieve widespread clinical use.

SUMMARY

A thorough review of Amifostine's development, mechanism of action, and current clinical status were conducted. A brief history of Amifostine is given, from its development at Walter Reid Institute of Research to its approval for clinical use. The mechanism of action of Amifostine is explored. The results of a complete literature review of all prospective randomized trials to date involving the use of Amifostine in radiation therapy are presented. The results are arranged by treatment site and salient findings discussed. Side effects and complications to consider in using Amifostine are reviewed. Key Messages: Amifostine has been explored as a radiation protectant in most radiation treatment sites. Studies have demonstrated efficacy of Amifostine in all treatment sites reviewed, but results are heterogeneous. The heterogeneity of studies looking at Amifostine as a clinical radiation protectant has precluded a definitive answer on its efficacy. Complicating its clinical use is its toxicity and delivery requirements. Amifostine has largely fallen out of use with the advent of intensity modulated radiation therapy (IMRT). However, side effects with IMRT remain a challenge and concern. The use of Amifostine in the IMRT era has been poorly explored and is worthy of future study.

Metabolomic studies in tissues of mice treated with amifostine and exposed to gamma-radiation

Although multiple radioprotectors are currently being investigated preclinically for efficacy and safety, few studies have investigated concomitant metabolic changes. This study examines the effects of amifostine on the metabolic profiles in tissues of mice exposed to cobalt-60 total-body gamma-radiation. Global metabolomic and lipidomic changes were analyzed using ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight mass spectrometry (QTOF-MS) in bone marrow, jejunum, and lung samples of amifostine-treated and saline-treated control mice. Results demonstrate that radiation exposure leads to tissue specific metabolic responses that were corrected in part by treatment with amifostine in a drug-dose dependent manner. Bone marrow exhibited robust responses to radiation and was also highly responsive to protective effects of amifostine, while jejunum and lung showed only modest changes. Treatment with amifostine at 200 mg/kg prior to irradiation seemed to impart maximum survival benefit, while the lower dose of 50 mg/kg offered only limited survival benefit. These findings show that the administration of amifostine causes metabolic shifts that would provide an overall benefit to radiation injury and underscore the utility of metabolomics and lipidomics to determine the underlying physiological mechanisms involved in the radioprotective efficacy of amifostine. This approach may be helpful in identifying biomarkers for radioprotective efficacy of amifostine and other countermeasures under development.

The efficacy and safety of amifostine for the acute radiation syndrome

Introduction: A radiation countermeasure that can be used prior to radiation exposure to protect the population from the harmful effects of radiation exposure remains a major unmet medical need and is recognized as an important area for research. Despite substantial advances in the research and development for finding nontoxic, safe, and effective prophylactic countermeasures for the acute radiation syndrome (ARS), no such agent has been approved by the United States Food and Drug Administration (FDA). Area covered: Despite the progress made to improve the effectiveness of amifostine as a radioprotector for ARS, none of the strategies have resolved the issue of its toxicity/side effects. Thus, the FDA has approved amifostine for limited clinical indications, but not for non-clinical uses. This article reviews recent strategies and progress that have been made to move forward this potentially useful countermeasure for ARS. Expert opinion: Although the recent investigations have been promising for fielding safe and effective radiation countermeasures, additional work is needed to improve and advance drug design and delivery strategies to get FDA approval for broadened, non-clinical use of amifostine during a radiological/nuclear scenario.

Phenomenological study: the experiences of patients with nasopharyngeal cancer after undergoing chemoradiation

Background

Chemoradiation is a combination therapy of chemotherapy and radiotherapy. Because chemotherapy is given together with radiotherapy, the side effects are heavier and more severe for some patients. For nasopharyngeal cancer patients, the side effects involve nausea, vomiting, anorexia, diarrhea, mucositis, xerostomia, and tasting and hearing loss, which influence their quality of life. The purpose of this study was to explore the experiences of patients with head and neck cancer undergoing chemoradiation.

Methods

A Phenomenogical desctipve, involving in depth interviewes was conducted during a 6 month study period. Eleven patiets with nasopharyngeal cancer participated in indepth inteviews Colaizzi’s method was used in analyzing data. The selection of participants in this study using purposive sampling method the inclusion criteria were1) the patient had been diagnosed with head and neck cancer, 2) minimum age of 18 years, and 3 had been received external chemoradiation, minimum 14 times of chmemoradiation. The study was conducted at one out-patientradiotherapy department. at Dharmais Cancer Centre Hospital, Jakarta.

Result

The findings show three main themes: 1) xerostomia was the main physical complaint, 2) patients had decreased social interaction, and 3) having adequate support from the family was important for patients.

Conclusion

The findings suggest involving family members when patients are undergoing chemoradiation. Adequate family support is needed to help the patients adapt to the side effects of chemoradiation with the best possible response.

Mechanisms for Radioprotection by Melatonin; Can it be Used as a Radiation Countermeasure?

BACKGROUND

Melatonin is a natural body product that has shown potent antioxidant property against various toxic agents. For more than two decades, the abilities of melatonin as a potent radioprotector against toxic effects of ionizing radiation (IR) have been proved. However, in the recent years, several studies have been conducted to illustrate how melatonin protects normal cells against IR. Studies proposed that melatonin is able to directly neutralize free radicals produced by IR, leading to the production of some low toxic products.

DISCUSSION

Moreover, melatonin affects several signaling pathways, such as inflammatory responses, antioxidant defense, DNA repair response enzymes, pro-oxidant enzymes etc. Animal studies have confirmed that melatonin is able to alleviate radiation-induced cell death via inhibiting pro-apoptosis and upregulation of anti-apoptosis genes. These properties are very interesting for clinical radiotherapy applications, as well as mitigation of radiation injury in a possible radiation disaster. An interesting property of melatonin is mitochondrial ROS targeting that has been proposed as a strategy for mitigating effects in radiosensitive organs, such as bone marrow, gastrointestinal system and lungs. However, there is a need to prove the mitigatory effects of melatonin in experimental studies.

CONCLUSION

In this review, we aim to clarify the molecular mechanisms of radioprotective effects of melatonin, as well as possible applications as a radiation countermeasure in accidental exposure or nuclear/radiological disasters.

Selenium as an adjuvant for modification of radiation response

Ionizing radiation plays a central role in several medical and industrial purposes. In spite of the beneficial effects of ionizing radiation, there are some concerns related to accidental exposure that could pose a threat to the lives of exposed people. This issue is also very critical for triage of injured people in a possible terror event or nuclear disaster. The most common side effects of ionizing radiation are experienced in cancer patients who had undergone radiotherapy. For complete eradication of tumors, there is a need for high doses of ionizing radiation. However, these high doses lead to severe toxicities in adjacent organs. Management of normal tissue toxicity may be achieved via modulation of radiation responses in both normal and malignant cells. It has been suggested that treatment of patients with some adjuvant agents may be useful for amelioration of radiation toxicity or sensitization of tumor cells. However, there are always some concerns for possible severe toxicities and protection of tumor cells, which in turn affect radiotherapy outcomes. Selenium is a trace element in the body that has shown potent antioxidant and radioprotective effects for many years. Selenium can potently stimulate antioxidant defense of cells, especially via upregulation of glutathione (GSH) level and glutathione peroxidase activity. Some studies in recent years have shown that selenium is able to mitigate radiation toxicity when administered after exposure. These studies suggest that selenium may be a useful radiomitigator for an accidental radiation event. Molecular and cellular studies have revealed that selenium protects different normal cells against radiation, while it may sensitize tumor cells. These differential effects of selenium have also been revealed in some clinical studies. In the present study, we aimed to review the radiomitigative and radioprotective effects of selenium on normal cells/tissues, as well as its radiosensitive effect on cancer cells.

A seleno-hormetine protects bone marrow hematopoietic cells against ionizing radiation-induced toxicities

2,2'-diselenyldibenzoic acid (DSBA) is a chemical probe produced to explore the pharmacological properties of diphenyldiselenide-derived agents with seleno-hormetic activity undergoing preclinical development. The present study was designed to verify in vivo the drug's properties and to determine mechanistically how these may mediate the protection of tissues against stress conditions, exemplified by ionizing radiation induced damage in mouse bone marrow. In murine bone marrow hematopoietic cells, the drug initiated the activation of the Nrf2 transcription factor resulting in enhanced expression of downstream stress response genes. This type of response was confirmed in human liver cells and included enhanced expression of glutathione S-transferases (GST), important in the metabolism and pharmacological function of seleno-compounds. In C57 BL/6 mice, DSBA prevented the suppression of bone marrow hematopoietic cells caused by ionizing radiation exposure. Such in vivo prevention effects were associated with Nrf2 pathway activation in both bone marrow cells and liver tissue. These findings demonstrated for the first time the pharmacological properties of DSBA in vivo, suggesting a practical application for this type of Se-hormetic molecules as a radioprotective and/or prevention agents in cancer treatments.

Radioprotective effects of mistletoe extract in zebrafish embryos in vivo

Introduction: Radioprotectors can enhance the efficacy of cancer radiotherapy, but their clinical use remains uncommon. The present study aimed to assess the radioprotective potential of mistletoe extract (commercial name: Abnoba Viscum), a well-known complementary cancer medicine, in zebrafish larvae. Materials and methods: Wild-type AB zebrafish embryos at 4 h-post-fertilization were exposed to 5 Gy 9-MeV electron beam irradiation after being treated for 1 h with 4 mMl/L amifostine or 0.2 mg/ml Abnoba Viscum A, F, M, or Q. Primary endpoints were abnormality-free survival and abnormality-free rates among survivors at 5 days-post-fertilization. Results: The crude abnormality-free survival rates were 33.7%, 49.0%, 38.8%, 43.9%, 38.1%, and 52.6%, whereas abnormality-free rates among survivors were 36.4%, 49.6%, 37.8%, 45.6%, 52.0%, and 62.8% for the control (with no pharmacologic treatment), amifostine, Abnoba Viscum A, F, M, and Q groups, respectively. Abnormality-free survival rates in the amifostine and Abnoba Viscum Q groups were significantly different from those in the control (p = .040 and .012, respectively), with an odds ratio (OR) of 1.90 [95% confidence interval (CI): 1.03-3.51] and 2.20 (95% CI: 1.19-4.08), respectively. Abnormality-free rates among survivors in the amifostine and Abnoba Viscum M and Q groups were significantly different from those in the control group (p = .048, .042, and <.001, respectively), with an OR of 1.79 (95% CI: 1.00-3.20), 1.82 (95% CI: 1.02-3.26), and 2.98 (1.67-5.33), respectively. Conclusion: Abnoba Viscum Q has at least a similar radioprotective effect to that of amifostine. Mistletoe extracts have been clinically applied for a long time and their effectiveness and feasibility have been verified. Abnoba Viscum Q might be a new candidate radioprotectant to enhance cancer radiotherapy efficacy.

Amifostine reduces inflammation and protects against 5-fluorouracil-induced oral mucositis and hyposalivation

Oral mucositis (OM) is a common and dose-limiting side effect of cancer treatment, including 5-fluorouracil (5-FU) and radiotherapy. The efficacy of the therapeutic measures to prevent OM is limited and disease prevention is not fully observable. Amifostine is a cytoprotective agent with a described anti-inflammatory potential. It is clinically used to reduce radiotherapy and chemotherapy-associated xerostomia. This study investigated the protective effect of amifostine on an experimental model of OM. Hamsters were divided into six groups: saline control group (5 mL/kg), mechanical trauma (scratches) of the right cheek pouch; 5-FU (60 and 40 mg/kg, ip, respectively, administered on days 1 and 2); amifostine (12.5, 25, or 50 mg/kg) + 5-FU + scratches. Salivation rate was assessed and the animals were euthanized on day 10 for the analysis of macroscopic and microscopic injury by scores. Tissue samples were harvested for the measurement of neutrophil infiltration and detection of inflammatory markers by ELISA and immunohistochemistry. 5-FU induced pronounced hyposalivation, which was prevented by amifostine (P<0.05). In addition, 5-FU injection caused pronounced tissue injury accompanied by increased neutrophil accumulation, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β) tissue levels, and positive immunostaining for TNF-α, IL-1β, and inducible nitric oxide synthase (iNOS). Interestingly, amifostine prevented the inflammatory reaction and consequently improved macroscopic and microscopic damage (P<0.05 vs 5-FU group). Amifostine reduced inflammation and protected against 5-FU-associated oral mucositis and hyposalivation.

Reactive Oxygen Species Drive Epigenetic Changes in Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) develops months to years after initial radiation exposure. RIF occurs when normal fibroblasts differentiate into myofibroblasts and lay down aberrant amounts of extracellular matrix proteins. One of the main drivers for developing RIF is reactive oxygen species (ROS) generated immediately after radiation exposure. Generation of ROS is known to induce epigenetic changes and cause differentiation of fibroblasts to myofibroblasts. Several antioxidant compounds have been shown to prevent radiation-induced epigenetic changes and the development of RIF. Therefore, reviewing the ROS-linked epigenetic changes in irradiated fibroblast cells is essential to understand the development and prevention of RIF.

Randomized double-blind trial of amifostine versus placebo for radiation-induced xerostomia in patients with head and neck cancer

INTRODUCTION

The role of the radioprotector amifostine in ameliorating radiotherapy side effects in head and neck squamous cell carcinoma (HNSCC) is controversial. This trial aimed to determine whether pretreatment with amifostine reduced the incidence of Radiation Therapy Oncology Group grade ≥2 acute and late xerostomia in patients receiving definitive or adjuvant radiotherapy for HNSCC, without reducing tumour control or survival.

METHODS

Between 14 September 2001 and 8 November 2004, 44 Royal Adelaide Hospital patients were randomized double-blind to receive amifostine (200 mg/m² IV) or placebo (normal saline IV) 5 days/week, prior to standard radiotherapy (60-70 Gy), each having ≥75% of the parotids treated to ≥40 Gy. Side effects were assessed weekly during treatment, at 3 and 5 months after radiotherapy, then every 6 months until disease progression or death.

RESULTS

The accrual target was 200 patients over 4-5 years, but the trial closed prematurely when only 44 patients had been randomized after 3 years. Of 41 evaluable patients, 80% (16/20) in the amifostine arm had grade ≥2 acute radiation salivary toxicity versus 76% (16/21) in the placebo arm (P = 1.00). The rate of grade ≥2 late radiation salivary toxicity at 12 months was 66% in the amifostine arm and 82% in the placebo arm (estimated hazard ratio 1.61, 95% confidence interval 0.74-3.49, P = 0.22). Other toxicities tended to be worse in the amifostine arm: acute grade 3-4 skin 35% vs 5% and mucous membrane 40% vs 5%; grade ≥2 vomiting 35% vs 5%, hypocalcaemia 25% vs 5% and fatigue 85% vs 33%, with only the latter retaining statistical significance after adjusting for multiple comparisons. There were no significant differences in failure-free (P = 0.70) or overall survival (P = 0.86), with estimated 4-year rates of 48% vs 54% and 49% vs 59% for the amifostine vs placebo arms respectively.

CONCLUSION

There was no clear evidence that pretreatment with amifostine made any difference to the incidence of grade ≥2 acute or late xerostomia. Other toxicity tended to be more severe with amifostine. There was no effect on failure-free or overall survival. Acknowledging the low statistical power, these results do not support the use of IV amifostine pre-radiotherapy in HNSCC.

Melatonin as an adjuvant in radiotherapy for radioprotection and radiosensitization

It is estimated that more than half of cancer patients undergo radiotherapy during the course of their treatment. Despite its beneficial therapeutic effects on tumor cells, exposure to high doses of ionizing radiation (IR) is associated with several side effects. Although improvements in radiotherapy techniques and instruments could reduce these side effects, there are still important concerns for cancer patients. For several years, scientists have been trying to modulate tumor and normal tissue responses to IR, leading to an increase in therapeutic ratio. So far, several types of radioprotectors and radiosensitizers have been investigated in experimental studies. However, high toxicity of chemical sensitizers or possible tumor protection by radioprotectors creates a doubt for their clinical applications. On the other hand, the protective effects of these radioprotectors or sensitizer effects of radiosensitizers may limit some type of cancers. Hence, the development of some radioprotectors without any protective effect on tumor cells or low toxic radiosensitizers can help improve therapeutic ratio with less side effects. Melatonin as a natural body hormone is a potent antioxidant and anti-inflammatory agent that shows some anti-cancer properties. It is able to neutralize different types of free radicals produced by IR or pro-oxidant enzymes which are activated following exposure to IR and plays a key role in the protection of normal tissues. In addition, melatonin has shown the ability to inhibit long-term changes in inflammatory responses at different levels, thereby ameliorating late side effects of radiotherapy. Fortunately, in contrast to classic antioxidants, some in vitro studies have revealed that melatonin has a potent anti-tumor activity when used alongside irradiation. However, the mechanisms of its radiosensitive effect remain to be elucidated. Studies suggested that the activation of pro-apoptosis gene, such as p53, changes in the metabolism of tumor cells, suppression of DNA repair responses as well as changes in biosynthesis of estrogen in breast cancer cells are involved in this process. In this review, we describe the molecular mechanisms for radioprotection and radiosensitizer effects of melatonin. Furthermore, some other proposed mechanisms that may be involved are presented.

Dimethyl Sulfoxide Prevents Radiation-Induced Oral Mucositis Through Facilitating DNA Double-Strand Break Repair in Epithelial Stem Cells

PURPOSE

Oral mucositis is one of the most prevalent side effects in patients undergoing radiation therapy for head and neck cancers. Current therapeutic agents such as palifermin recombinant human keratinocyte growth factor and amifostine do not efficiently or fully prevent mucositis. Dimethyl sulfoxide (DMSO), a free-radical scavenger, has shown therapeutic benefits in many preclinical and clinical studies. This study aimed to investigate the efficacy of DMSO in a clinically relevant mouse model of acute, radiation-induced oral mucositis.

METHODS AND MATERIALS

Oral mucositis was induced by a high single and fractioned irradiation of the head and neck area in C57BL/6J mice, and the effects of DMSO (by intraperitoneal injection) were assessed by macroscopic and histopathological examination. Epithelial stem and progenitor cells were analyzed by immunohistochemical staining of p63 and Ki-67, and DNA double-strand breaks (DSBs) were visualized by immunofluorescence detection of γ-H2AX. Tumor xenograft was obtained using CAL-27 cells.

RESULTS

Pretreatment with DMSO protected the oral mucosa from severe acute radiation injury, reduced the extent of radiation-induced weight loss, and had no significant effects on tumor weight in irradiated or nonirradiated xenograft mice. Furthermore, the efficacy of DMSO was superior to that of recombinant human keratinocyte growth factor and amifostine. DMSO treatment prevented the loss of proliferative lingual epithelial stem and progenitor cells upon irradiation. More interestingly, the average levels of γ-H2AX foci were significantly decreased in p63-positive epithelial stem cells at 6 hours, but not at 2 hours, after irradiation, indicating that DMSO facilitated DNA DSB repair rather than suppressing the indirect action of irradiation.

CONCLUSIONS

DMSO prevents the loss of proliferative lingual epithelial stem and progenitor cells upon irradiation by facilitating DNA DSB repair, thereby protecting against radiation-induced mucositis without tumor protection. Given its high efficacy and low toxicity, DMSO could be a potential treatment option to prevent radiation-induced oral mucositis.

Utility of polaprezinc in reducing toxicities during radiotherapy: a literature review

Chemoradiotherapy is important for treating malignancies. However, radiation-induced toxicities develop as chemoradiotherapy-related complications. Various agents reduce or prevent toxicities, but there are no standard treatments. Polaprezinc (PZ), a chelating compound used for gastric ulcers, has antioxidant and free radical scavenging effects. Although few studies have evaluated PZ and radiation-induced normal tissue damage, several clinical studies have shown the efficacy of PZ for oral mucositis, esophagitis, proctitis and taste alterations during and after radiotherapy. Moreover, preclinical data support the clinical data, indicating good potential of testing PZ in future trials. However, as there are only few well-documented review articles on PZ use in cancer treatment, we conducted this literature review. PZ reduced several radiation-induced toxicities and improved the quality of life.

Effectiveness and safety of different amifostine regimens: Preliminary results of a phase II multicenter randomized controlled trial

Objective

The radioprotective effects of amifostine remain uncertain in patients with nasopharyngeal carcinoma (NPC), and adverse effects and cost limit generalization of its classical everyday regimen. This phase II multicenter randomized controlled trial aimed to explore whether amifostine could ameliorate the toxicities of NPC patients in the era of intensity-modulated radiotherapy (IMRT), and to compare different regimens of amifostine on effectiveness and safety.

Methods

Patients with stage I-IVB NPC were involved prospectively from January 1st, 2013. All patients received radical treatment based on IMRT. After a randomization stratified by their stage, these patients were allocated into 3 groups: the group treated without amifostine, the group treated with the everyday regimen of amifostine, and the group treated with the every-other-day regimen. The 3 groups of patients were compared on radiotherapy-related acute toxicities, treatment effects of NPC, and amifostine-related complications. This trial was registered on the clinicaltrials.gov (ID: NCT01762514).

Results

Until August 31st, 2017, totally 187 patients completed experimental intervention. Only amifostine of everyday regimen appeared to reduce the patient proportion of mucositis (79.1% vs. 96.8%, P=0.002). Hypocalcemia was less common in patients treated without amifostine than in those treated with amifostine (22.6% vs. 53.4% vs. 41.8%, P=0.002). Neither complete remission rates nor the survivals were affected by amifostine.

Conclusions

Amifostine of everyday regimen could reduce mucositis in NPC patients who received IMRT, though it also had the possibility to cause more hypocalcemia.

Pharmacological modulation of radiation-induced oral mucosal complications

Radiation-induced mucositis is a common toxicity, especially in patients with head and neck cancers. Despite recent technological advances in radiation therapy, such as intensity-modulated radiotherapy, radiation-induced mucositis is still causing treatment disruptions, negatively affecting patients' long and short term quality of life, and impacting medical resources use with economic consequences. The objective of this article was to review the latest updates in the management of radiation-induced mucositis, with a focus on pharmaceutical strategies for the prevention or treatment of mucositis. Although numerous studies analysing the prevention and management of oral radiation-induced mucositis have been conducted, there are still few reliable data to guide daily clinical practice. Furthermore, most of the tested drugs have shown no (anti-inflammatory cytokine, growth factors) or limited (palifermin) effect. Therapies for acute oral mucositis are predominantly focused on improving oral hygiene and providing symptoms control. Although low-level laser therapy proved efficient in preventing radiation-induced oral mucositis in patients with head and neck cancer, this intervention requires equipment and trained medical staff, and is therefore insufficiently developed in clinical routine. New effective pharmacological agents able to prevent or reverse radio-induced mucositis are required.