Radiotherapy Exposure in Cancer Patients and Subsequent Risk of Stroke: A Systematic Review and Meta-Analysis

Comparative assessment of radiation therapy-induced vasculitis using [18F]FDG-PET/CT in patients with non-small cell lung cancer treated with proton versus photon radiotherapy

PURPOSE

To assess radiation therapy (RT)-induced vasculitis in patients with non-small cell lung cancer (NSCLC) by examining changes in the uptake of 18F-fluoro-D-deoxyglucose ([18F]FDG) by positron emission tomography/computed tomography (PET/CT) images of the ascending aorta (AA), descending aorta (DA), and aortic arch (AoA) before and after proton and photon RT.

METHOD

Thirty-five consecutive locally advanced NSCLC patients were definitively treated with proton (n = 27) or photon (n = 8) RT and concurrent chemotherapy. The patients were prospectively enrolled to undergo [18F]FDG-PET/CT imaging before and 3 months after RT. An adaptive contrast-oriented thresholding algorithm was applied to generate mean standardized uptake values (SUVmean) for regions of interest (ROIs) 3 mm outside and 3 mm inside the outer perimeter of the AA, DA, and AoA. These ROIs were employed to exclusively select the aortic wall and remove the influence of blood pool activity. SUVmeans before and after RT were compared using two-tailed paired t-tests.

RESULTS

RT treatments were associated with increased SUVmeans in the AA, DA, and AoA-1.9%, 0.3%, and 1.3% for proton and 15.8%, 9.5%, and 15.5% for photon, respectively. There was a statistically significant difference in the ∆SUVmean (post-RT SUVmean - pre-RT SUVmean) in patients treated with photon RT when compared to ∆SUVmean in patients treated with proton RT in the AA (p = 0.043) and AoA (p = 0.015). There was an average increase in SUVmean that was related to dose for photon patients (across structures), but that was not seen for proton patients, although the increase was not statistically significant.

CONCLUSION

Our results suggest that patients treated with photon RT for NSCLC may exhibit significantly more RT-induced inflammation (measured as ∆SUVmean) in the AA and AoA when compared to patients who received proton RT. Knowledge gained from further analyses in larger cohorts could aid in treatment planning and help prevent the significant morbidity and mortality associated with RT-induced vascular complications.

TRIAL REGISTRATION

NCT02135679.

Evaluation of risks of cardiovascular disease from radiation exposure linked to computed tomography scans in the UK

Epidemiological studies of patient populations have shown that high doses of radiation increase risks of cardiovascular disease (CVD). Results from a recent meta-analysis of 93 epidemiological studies covering a wide range of doses provided evidence of a causal association between radiation exposure and CVD, and indicated excess relative risk per Gy for maximum dose below 500 mGy or delivered at low dose rates. These doses cover the range of organ doses expected from multiple diagnostic computed tomography (CT) scans. Dose-effect factors for the excess absolute risk of mortality from CVD following radiation exposure were derived from the meta-analysis. The present study uses these factors to estimate excess risks of mortality for various types of CVD, including cerebrovascular disease (CeVD), from CT scans of the body and head, assuming that the meta-analytic factors were accurate and represented a causal relationship. Estimates are based on cumulative doses to the heart and brain from CT scans performed on 105 574 patients on 12 CT scanners over a period of 5½ years. The results suggest that the excess number of deaths from CeVD could be 7 or 26 per 100 000 patients depending whether threshold brain doses of 200 mGy or 50 mGy, respectively are assumed. These results could have implications for head CT scans. However, the results rely on the validity of risk factors derived in the meta-analysis informing this assessment and which include significant uncertainties. Further incidence studies should provide better information on risk factors and dose thresholds, particularly for CeVD following head CT scans.

RNA N6-Methyladenosine Modification in DNA Damage Response and Cancer Radiotherapy

The N6-methyladenosine (M6A) modification is the most common internal chemical modification of RNA molecules in eukaryotes. This modification can affect mRNA metabolism, regulate RNA transcription, nuclear export, splicing, degradation, and translation, and significantly impact various aspects of physiology and pathobiology. Radiotherapy is the most common method of tumor treatment. Different intrinsic cellular mechanisms affect the response of cells to ionizing radiation (IR) and the effectiveness of cancer radiotherapy. In this review, we summarize and discuss recent advances in understanding the roles and mechanisms of RNA M6A methylation in cellular responses to radiation-induced DNA damage and in determining the outcomes of cancer radiotherapy. Insights into RNA M6A methylation in radiation biology may facilitate the improvement of therapeutic strategies for cancer radiotherapy and radioprotection of normal tissues.

Statin use reduces radiation-induced stroke risk in advanced nasopharyngeal carcinoma patients

OBJECTIVE

This cohort study aimed to evaluate the impact of statin use on ischemic stroke risk in patients with advanced nasopharyngeal carcinoma (NPC) undergoing standard concurrent chemoradiotherapy (CCRT).

METHODS

Using data from the Taiwan Cancer Registry Database, we conducted an inverse probability of treatment-weighted Cox regression analysis to examine the association between statin use during CCRT and ischemic stroke risk.

RESULTS

The adjusted hazard ratio (aHR) for ischemic stroke in the statin group compared to the non-statin group was 0.70 (95 % CI: 0.54-0.92; P < 0.0107). This protective effect was observed across different statin classes, with hydrophilic statins such as pravastatin showing an aHR of 0.37 (95 % CI: 0.17-0.85) and lipophilic statins including atorvastatin displaying an aHR of 0.32 (95 % CI: 0.21-0.50) compared to non-statin use. Analysis of cumulative defined daily doses (cDDD) revealed a dose-response relationship, with lower stroke risk observed in higher quartiles of cDDD. Additionally, patients with a daily defined dose (DDD) > 1 had a reduced risk of stroke with an aHR of 0.49 (95 % CI: 0.31-0.63), while those with DDD ≤ 1 showed an aHR of 0.59 (95 % CI: 0.40-0.84).

CONCLUSIONS

Our study provides evidence supporting the beneficial effects of statin use during the CCRT period in reducing radiation-induced stroke risk among patients with advanced NPC undergoing definitive CCRT. Notably, pravastatin and atorvastatin demonstrated significant reductions in stroke occurrence. Furthermore, the findings suggest a dose-response relationship, where higher cumulative doses and greater daily dose intensity of statin use were associated with a lower risk of stroke.

Risk of stroke-specific mortality after radiotherapy in patients with primary brain tumours

Introduction

Stroke is an established complication in cancer patients, amongst whom brain tumour patients have the highest risk of fatal stroke. Radiotherapy is an important treatment for brain tumours and is associated with increased risk of cerebrovascular disease. However, the impact of brain irradiation on stroke-related deaths in brain tumour patients is unknown, and the timing of any effect uncertain. This study investigates the relationship between radiotherapy and stroke-specific mortality (SSM) in patients with primary brain tumours.

Methods

Patients of any age diagnosed with histologically confirmed primary brain tumours between 1992 and 2015 were abstracted from the Surveillance, Epidemiology, and End Results (SEER) database. Primary outcome was impact of radiotherapy on 5-year SSM. Cumulative SSM rates under competing risk assumptions were estimated and stratified by intervention type. Time-dependent hazard ratios were estimated to identify when the radiotherapy impact was greatest.

Results

85,284 patients with primary brain tumour diagnoses were analysed. Overall, the 5-year cumulative SSM rate was low (0.6%) with the highest rate (0.76%) in patients receiving no treatment, in whom it mainly occurred < 1 month after diagnosis. SSM rates were lower in patients treated with radiotherapy alone (0.27%) or radiotherapy plus surgery (0.24%); stroke-related deaths also occurred later in these groups. While these patterns were observed in both glioblastoma and non-glioblastoma patients, stroke deaths tended to occur later in non-glioblastoma patients receiving radiotherapy. Relative to the 'no treatment' group, the highest risk of stroke mortality in radiotherapy treated patients occurred 3.5-4 years after diagnosis.

Conclusion

The risk of SSM is low in patients with primary brain tumours and is not increased by radiotherapy. Two different patterns were observed: acute stroke mortality in patients receiving no treatment, and delayed stroke mortality in patients receiving radiotherapy (+/- surgery) with the latter peaking 3.5-4 years after diagnosis.

The Risk of Ischemic and Hemorrhagic Stroke in Head and Neck Cancer: A Longitudinal Cohort Study

Several studies have shown that head and neck cancer is associated with an increased risk of stroke incidence. However, investigations of the association between the two diseases based on a matching cohort dataset are still limited. Therefore, we identified the incidence and risk of stroke in patients with head and neck cancer using a nationwide population-based cohort dataset. A total of 5248 individuals without cancer and 1312 with cancer were enrolled from the dataset after a 4:1 propensity score matching. We found that the incidence of overall stroke (per 1000 person years) was 19.29 for those with head and neck cancer, consisting of 17.32 as ischemic type and 2.74 as hemorrhagic type. Additionally, patients with head and neck cancer had a significantly increased risk of overall and ischemic stroke development but not hemorrhagic stroke. Moreover, the risk of stroke development over time was relatively high within the first year after the diagnosis of head and neck cancer. However, in the subgroup analysis, oral cavity cancer survivors showed an increased risk of both ischemic and hemorrhagic strokes. Therefore, our nationwide population-based cohort study suggests that clinicians should closely monitor patients with head and neck cancers for the early detection of stroke.

Stroke death in patients receiving radiation for head and neck cancer in the modern era

Objectives

Head and neck cancer is a common malignancy frequently treated with chemotherapy and radiotherapy. Studies have shown an increased risk of stroke with the receipt of radiotherapy, but data on stroke-related mortality are limited, particularly in the modern era. Evaluating stroke mortality related to radiotherapy is vital given the curative nature of head and neck cancer treatment and the need to understand the risk of severe stroke in this population.

Methods

We analyzed the risk of stroke death among 122,362 patients (83,651 patients who received radiation and 38,711 patients who did not) with squamous cell carcinoma of the head and neck (HNSCC) diagnosed between 1973 and 2015 in the SEER database. Patients in radiation vs. no radiation groups were matched using propensity scores. Our primary hypothesis was that radiotherapy would increase the hazard of death from stroke. We also examined other factors impacting the hazard of stroke death, including whether radiotherapy was performed during the modern era when IMRT and modern stroke care were available as well as increased HPV-mediated cancers of the head and neck. We hypothesized that the hazard of stroke death would be less in the modern era.

Results

There was an increased hazard of stroke-related death in the group receiving radiation therapy (HR 1.203, p = 0.006); however, this was a very small absolute increase, and the cumulative incidence function of stroke death was significantly reduced in the modern era (p < 0.001), cohorts with chemotherapy (p=0.003), males (p=0.002), younger cohorts (p<0.001) and subsites other than nasopharynx (p=0.025).

Conclusions

While radiotherapy for head and neck cancer increases the hazard of stroke death, this is reduced in the modern era and remains a very small absolute risk.

Established and Emerging Cancer Therapies and Cardiovascular System: Focus on Hypertension-Mechanisms and Mitigation

Cardiovascular disease and cancer are 2 of the leading causes of death worldwide. Although improvements in outcomes have been noted for both disease entities, the success of cancer therapies has come at the cost of at times very impactful adverse events such as cardiovascular events. Hypertension has been noted as both, a side effect as well as a risk factor for the cardiotoxicity of cancer therapies. Some of these dynamics are in keeping with the role of hypertension as a cardiovascular risk factor not only for heart failure, but also for the development of coronary and cerebrovascular disease, and kidney disease and its association with a higher morbidity and mortality overall. Other aspects such as the molecular mechanisms underlying the amplification of acute and long-term cardiotoxicity risk of anthracyclines and increase in blood pressure with various cancer therapeutics remain to be elucidated. In this review, we cover the latest clinical data regarding the risk of hypertension across a spectrum of novel anticancer therapies as well as the underlying known or postulated pathophysiological mechanisms. Furthermore, we review the acute and long-term implications for the amplification of the development of cardiotoxicity with drugs not commonly associated with hypertension such as anthracyclines. An outline of management strategies, including pharmacological and lifestyle interventions as well as models of care aimed to facilitate early detection and more timely management of hypertension in patients with cancer and survivors concludes this review, which overall aims to improve both cardiovascular and cancer-specific outcomes.

When Two Maladies Meet: Disease Burden and Pathophysiology of Stroke in Cancer

Stroke and cancer are disabling diseases with an enormous global burden, disproportionately affecting vulnerable populations and low- and middle-income countries. Both these diseases share common risk factors, which warrant concerted attention toward reshaping population health approaches and the conducting of fundamental studies. In this article, an overview of epidemiological trends in the prevalence and burden of cancer and stroke, underlying biological mechanisms and clinical risk factors, and various tools available for risk prediction and prognosis are provided. Finally, future recommendations for research and existing gaps in our understanding of pathophysiology. Further research must investigate the causes that predispose patients to an increased risk of stroke and/or cancer, as well as biomarkers that can be used to predict growing morbidity and mortality.

Is stroke incidence increased in survivors of adult cancers? A systematic review and meta-analysis

PURPOSE

Existing research hints that people living with and beyond cancer are at an increased risk of stroke. However, there is insufficient evidence to appropriately inform guidelines for specific stroke prevention or management for cancer patients. We conducted a systematic review and meta-analysis to describe and quantify stroke incidence in people living with and beyond cancer.

METHODS

Medline, CINAHL, and EMBASE were searched for epidemiological studies comparing stroke incidence between cancer and non-cancer patients. Reviewers independently extracted data; random-effects meta-analyses and quality assessment were performed.

RESULTS

Thirty-six studies were narratively synthesised. Meta-analysis was conducted using seven studies. Methodological quality was high for most studies. Study populations were heterogeneous, and the length of follow-up and risk factors varied. There was a variation in risk between different cancer types and according to stroke type: pancreatic (HR 2.85 (95% CI 2.43-3.36), ischaemic) (HR 2.28 (95% CI 1.43-3.63), haemorrhagic); lung (HR 2.33 (95% CI 1.63-3.35), ischaemic) (HR 2.14 (95% CI 1.45-3.15), haemorrhagic); and head and neck (HR 1.54 (95% CI 1.40-1.69), haemorrhagic) cancers were associated with significantly increased incidence of stroke. Risk is highest within the first 6 months of diagnosis. Narrative synthesis indicated that several studies also showed significantly increased incidence of stroke in individuals with colorectal cancer, breast cancer, ovarian cancer, nasopharyngeal cancer, leukaemia, and myeloma, and those who have received radiotherapy for head and neck cancers and platinum-based chemotherapy may also have higher stroke incidence.

CONCLUSIONS

Stroke incidence is significantly increased after diagnosis of certain cancers.

IMPLICATIONS FOR CANCER SURVIVORS

Cardiovascular risk should be assessed during cancer survivorship care, with attention to modifying shared cancer/cardiovascular risk factors.

Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation

The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.

Cardiovascular Disease in Adult Cancer Survivors: a Review of Current Evidence, Strategies for Prevention and Management, and Future Directions for Cardio-oncology

PURPOSE OF REVIEW

Cardiovascular disease is long-term complication of both cancer and anti-cancer treatment and can have significant ramifications for health-related quality of life and mortality. This narrative review explores the current evidence linking cardiovascular disease and cancer, as well as exploring strategies for the prevention and management of cardiovascular disease, and outlines future opportunities in the field of cardio-oncology.

RECENT FINDINGS

Cancer confers risk for various cardiovascular diseases including heart failure, cardiomyopathy, arrhythmia, coronary heart disease, stroke, venous thromboembolism, and valvular heart disease. Cancer treatment, in particular agents such as platinum-based chemotherapy, anthracyclines, hormonal treatments, and thoracic radiotherapy, further increases risk. While cardiovascular disease can be identified early and effectively managed in cancer survivors, cardiovascular screening and management does not typically feature in routine long-term cancer care of adult cancer survivors. Cancer and cancer treatment can accelerate the development of cardiovascular disease. Further research into screening and management strategies for cardiovascular disease, along with evidence-based guidelines, is required to ensure adult cancer survivors receive appropriate long-term care.

Comparative Analysis of 60Co and 192Ir Sources in High Dose Rate Brachytherapy for Cervical Cancer

High-dose-rate (HDR) brachytherapy (BT) is an essential treatment for cervical cancer, one of the most prevalent gynecological malignant tumors. In HDR BT, high radiation doses can be delivered to the tumor target with the minimum radiation doses to organs at risk. Despite the wide use of the small HDR 192Ir source, as the technique has improved, the HDR 60Co source, which has the same miniaturized geometry, has also been produced and put into clinical practice. Compared with 192Ir (74 days), 60Co has a longer half-life (5.3 years), which gives it a great economic advantage for developing nations. The aim of the study was to compare 60Co and 192Ir sources for HDR BT in terms of both dosimetry and clinical treatment. The results of reports published on the use of HDR BT for cervical cancer over the past few years as well as our own research show that this treatment is safe and it is feasible to use 60Co as an alternative source.

Pencil-beam scanning proton therapy for the treatment of glomus jugulare tumours

INTRODUCTION

Glomus jugulare tumours (GJT) are benign tumours that arise locally and destructively in the base of the skull and can be successfully treated with radiotherapy. Patients have a long-life expectancy and the late effects of radiotherapy can be serious. Proton radiotherapy reduces doses to critical organs and can reduce late side effects of radiotherapy. The aim of this study was to report feasibility and early clinical results of 12 patients treated using proton therapy.

METHODS

Between December 2013 and June 2019, 12 patients (pts) with GJT (median volume 20.4 cm³ ; range 8.5-41 cm³ ) were treated with intensity modulated proton therapy (IMPT). Median dose was 54 GyE (Gray Equivalents) (50-60 GyE) with daily fractions of 2 GyE. Twelve patients were analysed with a median follow-up time of 42.2 months (11.3-86.7). Feasibility, dosimetric parameters, acute and late toxicity and local effect on tumour were evaluated in this retrospective study.

RESULTS

All patients finished treatment without interruption, with excellent dosimetric parameters and mild acute toxicity. Stabilisation of tumour size was detected on MRI in all patients. No changes in symptoms were observed in comparison with pre-treatment conditions. No late effects of radiotherapy were observed.

CONCLUSION

Pencil-beam scanning proton radiotherapy is highly feasible in the treatment of large GJT with mild acute toxicity and promising short-term results. Longer follow-up and larger patient cohorts are required to further identify the role of pencil-beam scanning (PBS) for this indication.

Risk of Developing Non-Cancerous Central Nervous System Diseases Due to Ionizing Radiation Exposure during Adulthood: Systematic Review and Meta-Analyses

Background: High-dose ionizing radiation (IR) (>0.5 Gy) is an established risk factor for cognitive impairments, but this cannot be concluded for low-to-moderate IR exposure (<0.5 Gy) in adulthood as study results are inconsistent. The objectives are to summarize relevant epidemiological studies of low-to-moderate IR exposure in adulthood and to assess the risk of non-cancerous CNS diseases. Methods: A systematic literature search of four electronic databases was performed to retrieve relevant epidemiological studies published from 2000 to 2022. Pooled standardized mortality ratios, relative risks, and excess relative risks (ERR) were estimated with a random effect model. Results: Forty-five publications were included in the systematic review, including thirty-three in the quantitative meta-analysis. The following sources of IR-exposure were considered: atomic bomb, occupational, environmental, and medical exposure. Increased dose-risk relationships were found for cerebrovascular diseases incidence and mortality (ERRpooled per 100 mGy = 0.04; 95% CI: 0.03−0.05; ERRpooled at 100 mGy = 0.01; 95% CI: −0.00−0.02, respectively) and for Parkinson’s disease (ERRpooled at 100 mGy = 0.11; 95% CI: 0.06−0.16); Conclusions: Our findings suggest that adult low-to-moderate IR exposure may have effects on non-cancerous CNS diseases. Further research addressing inherent variation issues is encouraged.

The Risk of Ischemic Stroke in Head and Neck Cancer Patients and Those Who Were Treated with Radiotherapy: A Population-Based Cohort Study

BACKGROUND

To investigate the standardized incidence ratios (SIR) of stroke in patients with head and neck cancer and their relationship to radiotherapy.

METHODS

Patients with head and neck cancer ages 20-85 years were enrolled from 2007 to 2016 using the Taiwan Cancer Registry. The study endpoint was fatal and non-fatal ischemic stroke, ascertained by the National Health Insurance Research Database. Age- and sex-adjusted SIRs, categorized by 10-year age standardization, were used to compare the patients with head and neck cancer with a randomly selected 2,000,000 general population. We compared the risk of stroke in patients with head and neck cancer who received radiotherapy or surgery alone. Multivariable adjusted hazard ratios (HR) and 95% confidence intervals (CI) were obtained from Cox regression analysis with competing risk.

RESULTS

Among 41,266 patients (mean age, 54.1 years; men, 90.6%) in the median follow-up period of 3.9 years, 1,407 strokes occurred. Compared with the general population, the overall SIR of stroke was 1.37 (95% CI, 1.30-1.44) in patients with head and neck cancer. In patients with head and neck cancer, the fully adjusted HR of stroke in those who received radiotherapy was 0.96 (95% CI, 0.83-1.10), compared with those who received surgery alone.

CONCLUSIONS

Patients with head and neck cancer had a higher risk of fatal or non-fatal ischemic stroke. The risk of stroke was not higher in patients initially treated with radiotherapy.

IMPACT

Oncologists should emphasize stroke prevention in all patients with head and neck cancer, not only in those who received radiotherapy.

Potential risks of cardiovascular and cerebrovascular disease and cancer due to cumulative doses received from diagnostic CT scans?

Potential risks from radiation exposure on the development of cardiovascular and cerebrovascular disease are indicated by epidemiological studies. Medical exposures give the largest dose to the population from artificial sources, with cumulative doses from multiple CT scans being significant. Data on doses from scans performed on 12 CT scanners in three hospitals over a period of 5½ years, derived using Radimetrics^TMsoftware, have been reviewed for 105 757 patients. Data have been downloaded for heart, brain, thyroid, and effective doses, and cumulative doses analysed using Excel^TMspreadsheets. 2.4% of patients having body CT scans received cumulative doses to the heart over 100 mSv, 9% of whom were under 50 years. 9.6% of patients having head CT scans received cumulative doses to the brain over 100 mSv with 0.08% over 500 mSv from whom 41% were under 50 years, but only 1.3% of patients scanned had thyroid/carotid artery doses over 100 mSv. An approximate evaluation of potential risks from exposures of the heart above 100 mSv and brain over 500 mSv for patients under 60 years would suggest that at most only one patient would demonstrate any excess risk from vascular disease resulting from the exposures. 0.67% of patients scanned received effective doses over 100 mSv, in line with results from European studies, with 8.4% being under 50 years. The application of age and sex specific risk coefficients relating to excess cancer incidence suggests that two or three patients with effective doses over 100 mSv and five patients with effective doses between 50 and 100 mSv, from those examined, might develop cancer as a result of exposure. However, this will be an overestimate, since it does not take patients' health into account. Exposure management software can aid in evaluating cumulative doses and identifying individual patients receiving substantial doses from repetitive imaging.

Risk of Stroke in Nasopharyngeal Cancer Survivors: A National Registry-Based Population Cohort Study

BackgroundWe aim to determine the risk of stroke and death within 30 days post stroke in nasopharyngeal cancer (NPC) survivors.MethodsWe conducted a population-based cohort study of patients diagnosed with NPC from Jan 1, 2005 to Dec 31, 2017. Using the cancer and stroke disease registries and the Singapore general population as the reference population, we report the age-standardized incidence rate differences (SIRDs) ratios (SIRs) and the cumulative incidence of stroke and the standardized mortality rate differences (SMRDs) and ratios (SMRs) for all causes of death within 30 days post stroke for NPC survivors.FindingsAt a median follow up of 48.4 months (IQR 19.8 - 92.9) for 3849 patients diagnosed with NPC, 96 patients developed stroke. The overall SIRD and SIR for stroke was 3.12 (95% CI 2.09 - 4.15) and 2.54 (95% CI 2.08 - 3.10) respectively. The SIRD was highest for the age group 70 - 79 years old (8.84 cases per 1000 person-years (PY); 0.46 - 17.21) while the SIR was highest for the age group 30 - 39 years old (16.41; 6.01 - 35.82). The SIRD and SIR for stage 1 disease was (6.96 cases per 1000 PY; 2.16 - 11.77) and (4.15; 2.46 - 7.00) respectively. The SMRD and SMR for all cause deaths within 30 days of stroke was (3.20 cases per 100 persons; -3.87 - 10.28) and (1.34; 0.76 - 2.37) respectively.InterpretationThe overall risk of stroke was markedly elevated in survivors of NPC, especially in Stage 1 disease when compared to the general population. The risk of death within 30 days of stroke was not significantly higher for NPC survivors.Classification of EvidenceThis study provides Class II evidence of the increased risk of stroke in survivors of nasopharyngeal cancer compared to general population.

LINCS gene expression signature analysis revealed bosutinib as a radiosensitizer of breast cancer cells by targeting eIF4G1

Radioresistance is the predominant cause for radiotherapy failure and disease progression, resulting in increased breast cancer‑associated mortality. Using gene expression signature analysis of the Library of Integrated Network‑Based Cellular Signatures (LINCS) and Gene Expression Omnibus (GEO), the aim of the present study was to systematically identify potential candidate radiosensitizers from known drugs. The similarity of integrated gene expression signatures between irradiated eukaryotic translation initiation factor 4 γ 1 (eIF4G1)‑silenced breast cancer cells and known drugs was measured using enrichment scores (ES). Drugs with positive ES were selected as potential radiosensitizers. The radiosensitizing effects of the candidate drugs were analyzed in breast cancer cell lines (MCF‑7, MX‑1 and MDA‑MB‑231) using CCK‑8 and colony formation assays following exposure to ionizing radiation. Cell apoptosis was measured using flow cytometry. The expression levels of eIF4G1 and DNA damage response (DDR) proteins were analyzed by western blotting. Bosutinib was identified as a promising radiosensitizer, as its administration markedly reduced the dosage required both for the drug and for ionizing radiation, which may be associated with fewer treatment‑associated adverse reactions. Moreover, combined treatment of ionizing radiation and bosutinib significantly increased cell killing in all three cell lines, compared with ionizing radiation or bosutinib alone. Among the three cell lines, MX‑1 cells were identified as the most sensitive to both ionizing radiation and bosutinib. Bosutinib markedly downregulated the expression of eIF4G1 in a dose‑dependent manner and also reduced the expression of DDR proteins (including ATM, XRCC4, ATRIP, and GADD45A). Moreover, eIF4G1 was identified as a key target of bosutinib that may regulate DNA damage induced by ionizing radiation. Thus, bosutinib may serve as a potential candidate radiosensitizer for breast cancer therapy.

Maintenance of Tight Junction Integrity in the Absence of Vascular Dilation in the Brain of Mice Exposed to Ultra-High-Dose-Rate FLASH Irradiation

Persistent vasculature abnormalities contribute to an altered CNS microenvironment that further compromises the integrity of the blood-brain barrier and exposes the brain to a host of neurotoxic conditions. Standard radiation therapy at conventional (CONV) dose rate elicits short-term damage to the blood-brain barrier by disrupting supportive cells, vasculature volume and tight junction proteins. While current clinical applications of cranial radiotherapy use dose fractionation to reduce normal tissue damage, these treatments still cause significant complications. While dose escalation enhances treatment of radiation-resistant tumors, methods to subvert normal tissue damage are clearly needed. In this regard, we have recently developed a new modality of irradiation based on the use of ultra-high-dose-rate FLASH that does not induce the classical pathogenic patterns caused by CONV irradiation. In previous work, we optimized the physical parameters required to minimize normal brain toxicity (i.e., FLASH, instantaneous intra-pulse dose rate, 6.9 · 106 Gy/s, at a mean dose rate of 2,500 Gy/s), which we then used in the current study to determine the effect of FLASH on the integrity of the vasculature and the blood-brain barrier. Both early (24 h, one week) and late (one month) timepoints postirradiation were investigated using C57Bl/6J female mice exposed to whole-brain irradiation delivered in single doses of 25 Gy and 10 Gy, respectively, using CONV (0.09 Gy/s) or FLASH (>106 Gy/s). While the majority of changes found one day postirradiation were minimal, FLASH was found to reduce levels of apoptosis in the neurogenic regions of the brain at this time. At one week and one month postirradiation, CONV was found to induce vascular dilation, a well described sign of vascular alteration, while FLASH minimized these effects. These results were positively correlated with and temporally coincident to changes in the immunostaining of the vasodilator eNOS colocalized to the vasculature, suggestive of possible dysregulation in blood flow at these latter times. Overall expression of the tight junction proteins, occludin and claudin-5, which was significantly reduced after CONV irradiation, remained unchanged in the FLASH-irradiated brains at one and four weeks postirradiation. Our data further confirm that, compared to isodoses of CONV irradiation known to elicit detrimental effects, FLASH does not damage the normal vasculature. These data now provide the first evidence that FLASH preserves microvasculature integrity in the brain, which may prove beneficial to cognition while allowing for better tumor control in the clinic.

Risk of ischaemic cerebrovascular events in head and neck cancer patients is associated with carotid artery radiation dose

BACKGROUND AND PURPOSE

Radiotherapy in the head and neck area may cause vascular damage to the carotid arteries, increasing the risk of anterior circulation ischaemic cerebrovascular events (ICVEs). However, limited data exists on the relationship between radiation dose to the carotid arteries and risk of ICVE. The purpose of this study was therefore to determine the relationship between radiation dose to the carotid arteries and anterior circulation ICVE risk.

MATERIALS AND METHODS

A retrospective analysis of a prospective study cohort of 750 head and neck cancer patients treated with definitive (chemo)radiotherapy was performed. Carotid arteries were delineated, and dose-volume parameters of the treatment plans were calculated. ICVEs were scored prospectively and checked retrospectively by analysing all patient records. Cox proportional hazards analysis was performed to analyse the dose-effect relationships.

RESULTS

The median follow-up period was 3.4 years, 27 patients experienced an ICVE and the 5-year cumulative risk was 4.6%. ICVE risk was significantly associated with dose to the carotid arteries. Multivariable analysis showed that the absolute volume (cm³) of the carotid arteries that received at least a radiation dose of 10 Gy was the most important prognostic factor for ICVE (HR = 1.11, AUC = 0.68, p < 0.001).

CONCLUSION

This is the first large prospective cohort study that demonstrates an independent dose-effect relationship between radiation dose to the carotid arteries and the risk of ICVE. These findings may be used to identify patients at risk for ICVE after radiotherapy who may benefit from primary or secondary preventive measures.

Risk of Stroke in Cancer Survivors: A Meta-analysis of Population-Based Cohort Studies

OBJECTIVE

Accumulating evidence suggests that cancer survivors may have a relatively higher risk of stroke. The aim of this meta-analysis was to determine whether cancer survivors have a relatively higher risk of stroke than cancer-free populations on the basis of published data from population-based cohort studies.

METHODS

PubMed, Embase, and Cochrane Library were searched from inception to February 8, 2020, for population-based cohort studies. Effect estimates with 95% confidence intervals (CIs) were pooled using the random-effects model. We conducted subgroup analyses and meta-regression to explore sources of heterogeneity and the stability of the results.

RESULTS

Twenty population-based cohort studies involving 10,479,530 participants were identified. Overall, the relative risk (RR) for stroke in cancer survivors was 1.66 (95% CI 1.35-2.04; p < 0.001) compared with that in cancer-free controls; survivors of head and neck, hematologic, lung, pancreas, and stomach cancer (all p < 0.05) showed consistently significant results, whereas no significant increased risk was observed for patients with other cancer types. The effects were more prominent in cancer survivors with female sex (RR 1.38, 95% CI 1.18-1.61; p < 0.001), younger age at cancer diagnosis (<45 years) (RR 2.57, 95% CI 1.27-5.19; p = 0.009), and shorter cancer survival duration (≥1-2 years) (RR 1.69, 95% CI 1.18-2.42; p = 0.004). Moreover, cancer survivors had a significantly increased risk of ischemic stroke (RR 1.53, 95% CI 1.28-1.84; p < 0.001) compared with hemorrhagic stroke.

CONCLUSIONS

Cancer plays a critical role in the etiologic of stroke. Due to the existence of substantial heterogeneity among the included studies, the results should be interpreted with caution. However, early prevention and effective intervention of stroke in cancer survivors require attention from health policy makers.

Prevalence of carotid plaque stenosis after head and neck radiotherapy – an observational study of 156 survivors

Summary: Background: Radiotherapy for head and neck cancer (HNC) represents a well-known predisposing factor for asymptomatic carotid artery lesions and acute cerebrovascular accidents. Our aim is to provide contemporary estimates on the prevalence, severity, and characteristics of carotid artery lesions in HNC survivors. Patients and methods: We prospectively included HNC patients who underwent radiotherapy and were free from the disease at the time of duplex ultrasound evaluation. Patients were re-contacted telephonically and those who agreed to participate were invited for an ambulatory visit when the investigators collected clinical information and performed duplex ultrasound examination based on a predefined protocol. Results: A total of 156 patients were included and underwent duplex ultrasound examination after a mean of 65.2 months from the last session of radiotherapy. A total of 36 patients (23.1%) had normal carotid arteries; mild, non-stenotic lesions were observed in 49.4% (n = 77) of patients; severe stenotic plaques were found in 27.5% (n = 43) of patients. One patient found with an asymptomatic occlusion of the left ICA. The prevalence of major cardiovascular risk factors and high radiation dose increased proportionally with plaque severity. Low echogenicity plaque was found in 59 (37.8%) patients on the right side and 57 (36.5%) on the left side; long segment plaque in 49 (31.4%) patients on the right side and in 47 (30.1%) on the left side; an atypical location of the lesions in 42 (26.9%) patients on the right side and in 48 (30.8%) on the left side. Conclusions: The prevalence of occlusion and severe stenosis after radiotherapy for HNC was very low in our study population. Low echogenicity plaque, long segment plaque, and an atypical location were common findings. Classic cardiovascular risk factors appear to have had a causative role: a routine screening of radiotherapy-treated patients might be necessary only in patients with concomitant cardiovascular risk factors or exposed to high-dose neck radiation.

Rate of radiation-induced microbleed formation on 7T MRI relates to cognitive impairment in young patients treated with radiation therapy for a brain tumor

BACKGROUND

Radiation therapy (RT) is essential to the management of many brain tumors, but has been known to lead to cognitive decline and vascular injury in the form of cerebral microbleeds (CMBs).

PURPOSE

In a subset of children, adolescents, and young adults recruited from a larger trial investigating arteriopathy and stroke risk after RT, we evaluated the prevalence of CMBs after RT, examined risk factors for CMBs and cognitive impairment, and related their longitudinal development to cognitive performance changes.

METHODS

Twenty-five patients (mean 17 years, range: 10-25 years) underwent 7-Tesla MRI and cognitive assessment. Nineteen patients were treated with whole-brain or focal RT 1-month to 20-years prior, while 6 non-irradiated patients with posterior-fossa tumors served as controls. CMBs were detected on 7T susceptibility-weighted imaging (SWI) using semi-automated software, a first use in this population.

RESULTS

CMB detection sensitivity with 7T SWI was higher than previously reported at lower field strengths, with one or more CMBs detected in 100% of patients treated with RT at least 1-year prior. CMBs were localized to dose-targeted brain volumes with risk factors including whole-brain RT (p = 0.05), a higher RT dose (p = 0.01), increasing time since RT (p = 0.03), and younger age during RT (p = 0.01). Apart from RT dose, these factors were associated with impaired memory performance. Follow-up data in a subset of patients revealed a proportional increase in CMB count with worsening verbal memory performance (r = -0.85, p = 0.03).

CONCLUSIONS

Treatment with RT during youth is associated with the chronic development of CMBs that evolve with memory impairment over time.

DNA damage response signaling pathways and targets for radiotherapy sensitization in cancer

Radiotherapy is one of the most common countermeasures for treating a wide range of tumors. However, the radioresistance of cancer cells is still a major limitation for radiotherapy applications. Efforts are continuously ongoing to explore sensitizing targets and develop radiosensitizers for improving the outcomes of radiotherapy. DNA double-strand breaks are the most lethal lesions induced by ionizing radiation and can trigger a series of cellular DNA damage responses (DDRs), including those helping cells recover from radiation injuries, such as the activation of DNA damage sensing and early transduction pathways, cell cycle arrest, and DNA repair. Obviously, these protective DDRs confer tumor radioresistance. Targeting DDR signaling pathways has become an attractive strategy for overcoming tumor radioresistance, and some important advances and breakthroughs have already been achieved in recent years. On the basis of comprehensively reviewing the DDR signal pathways, we provide an update on the novel and promising druggable targets emerging from DDR pathways that can be exploited for radiosensitization. We further discuss recent advances identified from preclinical studies, current clinical trials, and clinical application of chemical inhibitors targeting key DDR proteins, including DNA-PKcs (DNA-dependent protein kinase, catalytic subunit), ATM/ATR (ataxia–telangiectasia mutated and Rad3-related), the MRN (MRE11-RAD50-NBS1) complex, the PARP (poly[ADP-ribose] polymerase) family, MDC1, Wee1, LIG4 (ligase IV), CDK1, BRCA1 (BRCA1 C terminal), CHK1, and HIF-1 (hypoxia-inducible factor-1). Challenges for ionizing radiation-induced signal transduction and targeted therapy are also discussed based on recent achievements in the biological field of radiotherapy.

Emerging Challenges of Radiation-Associated Cardiovascular Dysfunction (RACVD) in Modern Radiation Oncology: Clinical Practice, Bench Investigation, and Multidisciplinary Care

Radiotherapy (RT) is a crucial treatment modality in managing cancer patients. However, irradiation dose sprinkling to tumor-adjacent normal tissues is unavoidable, generating treatment toxicities, such as radiation-associated cardiovascular dysfunction (RACVD), particularly for those patients with combined therapies or pre-existing adverse features/comorbidities. Radiation oncologists implement several efforts to decrease heart dose for reducing the risk of RACVD. Even applying the deep-inspiration breath-hold (DIBH) technique, the risk of RACVD is though reduced but still substantial. Besides, available clinical methods are limited for early detecting and managing RACVD. The present study reviewed emerging challenges of RACVD in modern radiation oncology, in terms of clinical practice, bench investigation, and multidisciplinary care. Several molecules are potential for serving as biomarkers and therapeutic targets. Of these, miRNAs, endogenous small non-coding RNAs that function in regulating gene expression, are of particular interest because low-dose irradiation, i.e., 200 mGy (one-tenth of conventional RT daily dose) induces early changes of pro-RACVD miRNA expression. Moreover, several miRNAs, e.g., miR-15b and miR21, involve in the development of RACVD, further demonstrating the potential bio-application in RACVD. Remarkably, many RACVDs are late RT sequelae, characterizing highly irreversible and progressively worse. Thus, multidisciplinary care from oncologists and cardiologists is crucial. Combined managements with commodities control (such as hypertension, hypercholesterolemia, and diabetes), smoking cessation, and close monitoring are recommended. Some agents show abilities for preventing and managing RACVD, such as statins and angiotensin-converting enzyme inhibitors (ACEIs); however, their real roles should be confirmed by further prospective trials.

Vitamin D, gut microbiota, and radiation-related resistance: a love-hate triangle

Radiation resistance is a serious issue in radiotherapy. Increasing evidence indicates that the human gut microbiome plays a role in the development of radiation resistance. Vitamin D is an important supplement for cancer patients treated with radiotherapy. Against this background, this paper reviewed research regarding the associations among vitamin D, microbiota dysbiosis, and radiation resistance. A hypothesis is developed to describe the relationships among vitamin D, the gut microbiota, and radiotherapy outcomes. Radiotherapy changes the composition of the gut microbiota, which in turn influence the serum level of vitamin D, and its distribution and metabolism in the body. Alteration of vitamin D level influences the patient response to radiotherapy, where the underlying mechanisms may be associated with the intestinal microenvironment, immune molecules in the intestines, gut microbiome metabolites, and signaling pathways associated with vitamin D receptors. Our understanding of the contribution of vitamin D and the gut microbiota to radiotherapy outcomes has been increasing gradually. A better understanding of the relationships among vitamin D, the gut microbiota, and radiotherapy outcomes will shed more light on radiation resistance, and also promote the development of new strategies for overcoming it, thus addressing an important challenge associated with the currently available radiotherapy modalities for cancer patients.

Effects of moderate red wine on cardiovascular risk factors in diabetics: a systematic review and meta-analysis of randomized controlled trials

Background: Diabetes mellitus is of major public health concerns; its incidence is continuously increasing. Diabetes mellitus is associated with a high risk of cardiovascular complications such as hypertension. Red wine has been reported to reduce cardiovascular risk factors. We quantified the effects of red wine on cardiovascular factors. Methods: We retrieved English-language articles published from January 1990 to April 2019. Cardiovascular risk factors were compared using means with 95% confidence intervals (95% CIs). Results: We identified five eligible randomized controlled trials. Diabetic patients who drank red wine exhibited significantly reduced systolic blood pressure (BP) (mean difference [MD] -1.33, 95% CI -1.81, -0.85) and diastolic BP (MD -1.31, 95% CI -1.80, -0.83) than those who did not. Compared to the observations for diabetics who did not drink red wine, the high-density lipoprotein (HDL) level was significantly higher in red wine drinkers (MD -0.24, 95% CI -0.39, -0.09). However, red wine had no effect on the body mass index (BMI) (MD -0.27, 95% CI -1.80, 1.25), the total cholesterol level (MD 0.13, 95% CI -0.17, 0.44), or the low-density lipoprotein (LDL) level (MD 0.08, 95% CI -0.21, 0.37). Conclusions: Red wine consumption significantly lowered BP and increased the HDL level in diabetics. Red wine had no significant effect on BMI or cholesterol and LDL levels. Given the heterogeneity of the studied populations and the lack of standardization and completeness across the published studies, caution is required while interpreting these findings.

Analysis of lncRNA and mRNA Transcriptomes Expression in Thyroid Cancer Tissues Among Patients With Exposure of Medical Occupational Radiation

Background:

Occupational exposure of radiation among medical radiation workers contributes to the subsequent increased risk of thyroid cancer. Long noncoding RNAs (lncRNAs) are emerging as important regulators of cancer biology. However, little is known about lncRNA expression in thyroid cancer tissues from patients who are exposed to medical occupational radiation. The purpose of this study is to reveal the transcriptomes difference between thyroid cancer tissues and adjacent nonneoplastic thyroid tissues.

Methods:

Microarray technology was used in this study. Quantitative reverse transcription polymerase chain reaction was adopted to verify 6 differentially expressed lncRNAs. Gene ontology and pathway analyses were performed using standard enrichment computational methods. Potential target genes of the differentially expressed lncRNAs were predicted with 2 independent algorithms.

Results:

A total of 23 lncRNA and messenger RNA transcripts were found differentially expressed in the thyroid cancer tissues (fold change ≥2.0, P < .05). This differential lncRNA expression may affect many pathways, including those involved in cysteine and methionine metabolism, Huntington disease, propanoate metabolism, and carcinogenesis.

Conclusions:

Our study provides a transcriptome-wide screening and analysis of the lncRNA expression profile in thyroid cancer tissues from patients with medical occupational radiation exposure and lays the foundation for further investigation of lncRNAs related to thyroid cancer development and carcinogenic risk of medical occupational radiation exposure.