Radiotherapy dosage:A neural network approach for uninvolved liver dose in stereotactic body radiation therapy for liver cancer

A recent study by Zhang et al developed a neural network-based predictive model for estimating doses to the uninvolved liver during stereotactic body radiation therapy(SBRT)in liver cancer.The study reported a significant advancement in personalized radiotherapy by improving accuracy and reducing treatment-related toxicity.The model demonstrated strong predictive performance with R-values above 0.8,indicating its potential to improve treatment consistency.However,concerns arise from the small sample size and exclusion criteria,which may limit generalizability.Future studies should incorporate larger,more diverse patient cohorts,explore potential confounding factors such as tumor characteristics and delivery technique variability,and address the long-term effects of SBRT.

Advances in radiotherapy in the treatment of esophageal cancer

Recent advancements in radiotherapy for esophageal cancer have significantly improved treatment outcomes and patient quality of life.Traditional radiotherapy techniques have been enhanced by the integration of advanced imaging and precision targeting technologies,such as intensity-modulated radiotherapy and proton therapy,which allow for more accurate tumor targeting while minimizing damage to surrounding healthy tissues.Additionally,combining radiotherapy with immunotherapy has shown promising results,leveraging the body’s im-mune response to enhance the effectiveness of cancer treatment.Studies have also highlighted the benefits of neoadjuvant chemoradiation followed by surgical resection,which has been associated with improved overall survival rates com-pared to radiotherapy alone.These innovations are paving the way for more effe-ctive and personalized treatment strategies,offering new hope for patients with esophageal cancer.

Stereotactic body radiotherapy in pancreatic adenocarcinoma

Background:Stereotactic body radiotherapy(SBRT)in pancreatic cancer allows high delivery of radiation doses on tumors without affecting surrounding tissue.This review aimed at the SBRT application in the treatment of pancreatic cancer.Data sources:We retrieved articles published in MEDLINE/PubMed from January 2017 to December 2022.Keywords used in the search included:“pancreatic adenocarcinoma”OR“pancreatic cancer”AND“stereotactic ablative radiotherapy(SABR)”OR“stereotactic body radiotherapy(SBRT)”OR“chemoradiotherapy(CRT)”.English language articles with information on technical characteristics,doses and fractionation,indications,recurrence patterns,local control and toxicities of SBRT in pancreatic tumors were included.All articles were assessed for validity and relevant content.Results:Optimal doses and fractionation have not yet been defined.However,SBRT could be the standard treatment in patients with pancreatic adenocarcinoma in addition to CRT.Furthermore,the combination of SBRT with chemotherapy may have additive or synergic effect on pancreatic adenocarcinoma.Conclusions:SBRT is an effective modality for patients with pancreatic cancer,supported by clinical practice guidelines as it has demonstrated good tolerance and good disease control.SBRT opens a possibility of improving outcomes for these patients,both in neoadjuvant treatment and with radical intent.

Potential of non-Western medicines in chemoradiotherapy for cervical cancer

This editorial explores the potential integration of non-Western medicine into radiotherapy for cervical cancer.While radiotherapy remains a radical treatment for cervical cancer,its associated toxicity and decline in quality of life can significantly impact patients’lives.Currently,most treatments are supportive,with no specific treatment options available in Western medicine.Non-Western medicine,often less toxic and easier to administer,has shown promising results when used alongside radiotherapy for cervical cancer.Despite these potential benefits,challenges such as limited evidence and restricted application areas persist.While non-Western medicines may offer potential improvements in chemoradiotherapy outcomes for cervical cancer,further research is necessary to substantiate these benefits.

Validation of the prognostic model for palliative radiotherapy in older patients with cancer

BACKGROUND Older patients are more likely to have a poor performance status and comor-bidities.There is a reluctance to extensively investigate and treat older patients.As elderly individuals and patients with neoplasms each increase in number,palliative treatment of older patients is expected to grow as an issue.AIM To investigated the role of palliative radiotherapy in older patients and patients who were expected to demonstrate a therapeutic effect.METHODS From February 2019 to February 2022,33 patients aged≥80 years underwent palliative radiotherapy.The prognosis in palliative care study predictor(PiPS),palliative prognostic index(PPI),and delirium-palliative prognostic score(D-PaP)models were used for prognosis prediction.D-PaP scores calculated according to the doctor's prediction of clinical prediction of survival(CPS)were excluded and then analyzed for comparison.Radiation was prescribed at a dose of 2.5-7 Gy per fraction,up to a median of 39 Gy10(range,28-75 Gy10).RESULTS The median follow-up was 2.4 months(range,0.2-27.5 months),and 28 patients(84.8%)showed subjective symptom improvements following treatment.The 2-and 6-month survival rates of all patients were 91.5%and 91.5%,respectively.According to regression analysis,the performance status index,symptom type,and radiation dose all showed no significant correlation with the treatment re-sponse.When survival was expected for>55 days in the PiPS model,the 2-month survival rate was 94.4%.For patients with PPI and D-PaP-CPS values of 0-3.9 points,the 2-month survival rates were 90.0%and 100%,respectively.For patients with a score of≥4 points,the 2-month survival rates were 37.5%and 0%,res-pectively.Core Tip:This is a retrospective study to investigate the role of palliative radiotherapy in older patients and patients who were expected to demonstrate a great therapeutic effect.The prognosis in palliative care study predictor,palliative prognostic index,and delirium-palliative prognostic score models were used for prognosis prediction.Most of patients showed subjective symptom improvements following treatment.The prognosis prediction model showed good correlation with survival.In order to increase the therapeutic effectiveness in palliative radiotherapy,it is necessary to assess a patient's exact prognosis and select appropriate patients accordingly.INTRODUCTION The incidence of cancer is high among individuals 60-69 years old and is 11 times greater among those≥65-years-old compared to those<65-years-old.For this reason,about half of all cancer cases are diagnosed in individuals aged≥70 years,and older patients account for a large portion of the total population regarding the prevalence of cancer[1].Cancer is one of the most significant diseases in older patients.About 60%of all cancer-related deaths occur in older patients aged 70 years[1,2].Moreover,cancer accounts for about one-third of the causes of death in the elderly population[1,2].When choosing a cancer treatment,both the characteristics of the cancer and the overall health status of the patient,such as their general condition and any underlying diseases,should be considered[2].Older patients have a shorter life expectancy than younger patients;moreover,they typically have many accompanying underlying diseases and have a poorer general condition.For this reason,older patients are often rejected from receiving active testing and treatment services.Therefore,even if other factors,such as the underlying disease,are the same in young and old patients,older patients typically receive less treatment due to the simple fact that they are older[3].Palliative treatment is a treatment approach that improves the pain and symptoms of a patient and their quality of life.Although palliative treatment is applicable regardless of patient age and the type and severity of their disease,most patients requiring palliative treatment are cancer patients.Palliative radiotherapy is relatively effective for cancer patients and tends to be a well-tolerated treatment.Although some studies have reported the usefulness of palliative radiotherapy in elderly patients,a large number of patients and caregivers are not receiving treatment due to fears of treatment,the risks of side effects,and doubts about treatment effectiveness[1].Since actual age is not always associated with physical ability,the determination of treatment based solely on age can be an obstacle preventing appropriate treatment opportunities.The importance of palliative care is increasing due to the recent growth of the elderly population,as well as,the increase in cancer incidence,and the changes in traditional views or perceptions,such as a growing acceptance of the pursuit of a dignified death[4].Therefore,in this study,we investigated the role of palliative radiotherapy in older patients and in patients who are expected to show a great therapeutic effect.

Identifying adipocyte-derived exosomal miRNAs as potential novel prognostic markers for radiotherapy of esophageal squamous cell carcinoma

BACKGROUND Radiation resistance limits radiotherapy efficacy in esophageal squamous cell carcinoma(ESCC).The tumor microenvironment,particularly adipocytes,plays a role in promoting cancer progression.Extracellular vesicles and microRNAs(miRNAs)regulate gene expression and hold prognostic potential for esophageal carcinoma.Elucidating radioresistance mechanisms and identifying radiosensitization targets can help enhance radiotherapy efficacy for esophageal cancer.AIM To investigate the potential role of miRNAs derived from adipocyte exosomes as prognostic markers for radiotherapy efficacy in ESCC.METHODS Free adipocytes were isolated from human thoracic adipose tissue.A co-culture model of adipocytes and ESCC cells was established to observe colony formation and cell survival post-irradiation.ESCC cell apoptosis was assessed by flow cytometry.Western Blot and immunofluorescence assays were performed to evaluate DNA damage in ESCC cells post-irradiation.Adipocyte-derived exosomes were isolated by ultracentrifugation and identified by electron microscopy.A similar set of experiments was performed on ESCC cells to analyze cell survival,apoptosis,and DNA damage post-radiation exposure.Exosomes from adipose tissue and serum exosomes from ESCC patients pre-and post-radiotherapy were subjected to high-throughput miRNA-sequencing and validated using real-time quantitative polymerase chain reaction.The correlation between potential target miRNAs and the short-term prognosis of radiotherapy in ESCC was evaluated by receiver operating characteristic curve analysis.RESULTS Co-culturing adipocytes with ESCC cells enhanced radioresistance,as evidenced by increased colony formation.Adipocyte co-culture reduced ESCC cell apoptosis and DNA damage post-radiation.Adipocyte-derived exosomes similarly conferred radioresistance in ESCC cells,decreasing apoptosis and DNA damage post-irradiation.Highthroughput miRNA-sequencing identified miR-660-5p in serum and adipose tissue exosomes.Patients with high expression of serum exosome miR-660-5p showed poor prognosis after radiotherapy.CONCLUSION Adipocyte-derived exosomal miR-660-5p is a potential biomarker for evaluating radiotherapy efficacy in ESCC.

Safety and effectiveness of induction chemoimmunotherapy followed by definitive radiotherapy or concurrent chemoradiotherapy in esophageal squamous cell carcinoma

BACKGROUND Esophageal squamous cell carcinoma(ESCC)is a common malignancy in China,often diagnosed at an advanced stage,with poor prognosis.Standard treatments such as definitive chemoradiotherapy offer limited survival benefits.Recent advances in immune checkpoint inhibitors combined with chemotherapy have shown promise,but their effectiveness and safety in conjunction with radio-therapy for unresectable ESCC require further exploration.AIM To assess the safety and effectiveness of induction chemoimmunotherapy fo-llowed by definitive radiotherapy or concurrent chemoradiotherapy(CCRT)in locally advanced unresectable ESCC.METHODS This retrospective study included 80 patients with locally advanced unresectable ESCC who underwent induction chemoimmunotherapy followed by definitive radiotherapy,recruited from Zhejiang Cancer Hospital.All patients received 2-4 cycles of chemotherapy plus programmed cell death 1/programmed cell death ligand 1 inhibitor,were re-evaluated to be inoperable,then received definitive radiotherapy or CCRT.Primary endpoint was treatment safety and tolerance.SPSS 26.0 software was used for data analysis.Th Kaplan-Meier method was used for survival analysis.RESULTS Thirty-seven(46.3%)patients received CCRT and 43(53.7%)received radiotherapy alone.The most common treatment-related adverse events included radiation esophagitis(32/80,40.0%)and anemia(49/80,61.3%),with 22(27.5%)experiencing grade≥3 adverse events.No treatment-related deaths occurred.After median follow-up of 16.5 months,the median progression-free survival(PFS)was 14.2 months,and median overall survival(OS)was 19.9 months.The 1-year and 2-year PFS and OS were 55.8%and 31.6%,and 67.5%and 44.1%,respectively.Patients with partial response had better outcomes than those with stable disease:1-year PFS 69.4%vs 43.9%(P=0.011)and OS 83.2%vs 48.8%(P=0.007).Induction therapy effectiveness and immunotherapy maintenance were independent prognostic factors for OS.CONCLUSION Chemotherapy combined with programmed cell death 1/programmed cell death ligand 1 inhibitor followed by definitive radiotherapy or CCRT in patients with locally advanced ESCC was safe and effective.

Precision radiotherapy for brain tumors A 10-year bibliometric analysis

OBJECTIVE： Precision radiotherapy plays an important role in the management of brain tumors. This study aimed to identify global research trends in precision radiotherapy for brain tumors using a bibliometric analysis of the Web of Science. DATA RETRIEVAL： We performed a bibliometric analysis of data retrievals for precision radiotherapy for brain tumors containing the key words cerebral tumor, brain tumor, intensity-modulated radiotherapy, stereotactic body radiation therapy, stereotactic ablative radiotherapy, imaging-guided radiotherapy, dose-guided radiotherapy, stereotactic brachytherapy, and stereotactic radiotherapy using the Web of Science. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed articles on precision radiotherapy for brain tumors which were published and indexed in the Web of Science; （b） type of articles： original research articles and reviews; （c） year of publication： 2002-2011. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） Corrected papers or book chapters. MAIN OUTCOME MEASURES： （1） Annual publication output; （2） distribution according to country; （3） distribution according to institution; （4） top cited publications; （5） distribution according to journals; and （6） comparison of study results on precision radiotherapy for brain tumors. RESULTS： The stereotactic radiotherapy, intensity-modulated radiotherapy, and imaging-guided radiotherapy are three major methods of precision radiotherapy for brain tumors. There were 260 research articles addressing precision radiotherapy for brain tumors found within the Web of Science. The USA published the most papers on precision radiotherapy for brain tumors, followed by Germany and France. European Synchrotron Radiation Facility, German Cancer Research Center and Heidelberg University were the most prolific research institutes for publications on precision radiotherapy for brain tumors. Among the top 13 research institutes publishing in this field, seven are in the USA, three are in Germany, two are in France, and there is one institute in India. Research interests including urology and nephrology, clinical neurology, as well as rehabilitation are involved in precision radiotherapy for brain tumors studies. CONCLUSION： Precision radiotherapy for brain tumors remains a highly active area of research and development.

Hemostatic radiotherapy for bleeding gastrointestinal

Hemostatic radiotherapy is a non-invasive treatment for bleeding gastrointestinal(GI)tumors,promoting tumor shrinkage,blood supply reduction,and fibrotic tissue formation.It is effective in cases where traditional interventions are insufficient or contraindicated and can prevent recurrent bleeding in patients with GI bleeding histories.Hypofractionation schedules are also effective for tumor control and patient compliance.

Postoperative chemoradiotherapy with capecitabine and oxaliplatin vs.capecitabine for pathological stage N2 rectal cancer

Objective:Several studies have been conducted on the effects and toxicity of adding oxaliplatin to fluorouracilbased or capecitabine-based chemoradiotherapy(CRT)regimens as significantly increasing the toxic response without benefit to survival.In this study,we further explored the role of these two postoperative CRT regimens in patients with pathological stage N2 rectal cancer.Methods:This study was a subgroup analysis of a randomized clinical trial.A total of 180 patients with pathological stage N2 rectal cancer were eligible,85 received capecitabine with radiotherapy(RT),and 95 received capecitabine and oxaliplatin with RT.Patients in both groups received adjuvant chemotherapy[capecitabine and oxaliplatin(XELOX);or fluorouracil,leucovorin,and oxaliplatin(FOLFOX)]after CRT.Results:At a median follow-up of 59.2[interquartile range(IQR),34.0−96.8]months,the three-year diseasefree survival(DFS)was 53.3%and 64.9%in the control group and the experimental group,respectively[hazard ratio(HR),0.63;95%confidence interval(95%CI),0.41−0.98;P=0.04].There was no significant difference between the groups in overall survival(OS)(HR,0.62;95%CI,0.37−1.05;P=0.07),the incidence of locoregional recurrence(HR,0.62;95%CI,0.24−1.64;P=0.33),the incidence of distant metastasis(HR,0.67;95%CI,0.42−1.06;P=0.09)and grade 3−4 acute toxicities(P=0.78).For patients with survival longer than 3 years,the conditional overall survival(COS)was significantly better in the experimental group(HR,0.39;95%CI,0.16−0.96;P=0.03).Conclusions:Our results indicated that adding oxaliplatin to capecitabine-based postoperative CRT is safe and effective in patients with pathological stage N2 rectal cancer.

Present situation and prospect of immunotherapy for unresectable locally advanced esophageal cancer during peri-radiotherapy

Four major studies(Checkmate577,Keynote-590,Checkmate649 and Attraction-4)of locally advanced esophageal cancer published in 2020 have established the importance of immunotherapy,represented by anti-programmed death protein(PD)-1 in postoperative adjuvant treatment and advanced first-line treatment of locally advanced or advanced esophageal cancer and esophagogastric junction cancer,from the aspects of proof of concept,long-term survival,overall survival rate and progression-free survival.For unresectable or inoperable nonmetastatic esophageal cancer,concurrent radiotherapy and chemotherapy is the standard treatment recommended by various guidelines.Because its curative effect is still not ideal,it is necessary to explore radical radiotherapy and chemotherapy in the future,and it is considered to be promising to combine them with immunotherapeutic drugs such as anti-PD-1.This paper mainly discusses how to combine radical concurrent radiotherapy and chemotherapy with immunotherapy for unresectable local advanced esophageal cancer.

Targeting the organelle for radiosensitization in cancer radiotherapy

Radiotherapy is a well-established cytotoxic therapy for local solid cancers, utilizing high-energy ionizing radiation to destroy cancer cells. However, this method has several limitations, including low radiation energy deposition, severe damage to surrounding normal cells, and high tumor resistance to radiation. Among various radiotherapy methods, boron neutron capture therapy (BNCT) has emerged as a principal approach to improve the therapeutic ratio of malignancies and reduce lethality to surrounding normal tissue, but it remains deficient in terms of insufficient boron accumulation as well as short retention time, which limits the curative effect. Recently, a series of radiosensitizers that can selectively accumulate in specific organelles of cancer cells have been developed to precisely target radiotherapy, thereby reducing side effects of normal tissue damage, overcoming radioresistance, and improving radiosensitivity. In this review, we mainly focus on the field of nanomedicine-based cancer radiotherapy and discuss the organelle-targeted radiosensitizers, specifically including nucleus, mitochondria, endoplasmic reticulum and lysosomes. Furthermore, the organelle-targeted boron carriers used in BNCT are particularly presented. Through demonstrating recent developments in organelle-targeted radiosensitization, we hope to provide insight into the design of organelle-targeted radiosensitizers for clinical cancer treatment.

Neoadjuvant radiotherapy dose escalation for locally advanced rectal cancers in the new era of radiotherapy:A review of literature

BACKGROUND The standard treatment of locally advanced rectal cancers(LARC)consists on neoadjuvant chemoradiotherapy followed by total mesorectal excision.Different data in literature showed a benefit on tumor downstaging and pathological complete response(pCR)rate using radiotherapy dose escalation,however there is shortage of studies regarding dose escalation using the innovative techniques for LARC(T3-4 or N1-2).AIM To analyze the role of neoadjuvant radiotherapy dose escalation for LARC using innovative radiotherapy techniques.METHODS In December 2020,we conducted a comprehensive literature search of the following electronic databases:PubMed,Web of Science,Scopus and Cochrane library.The limit period of research included articles published from January 2009 to December 2020.Screening by title and abstract was carried out to identify only studies using radiation doses equivalent dose 2 Gy fraction(EQD2)≥54 Gy and Volumetric Modulated Arc Therapy(VMAT),intensity-modulated radiotherapy or image-guided radiotherapy(IGRT)techniques.The authors’searches generated a total of 2287 results and,according to PRISMA Group(2009)screening process,21 publications fulfil selection criteria and were included for the review.RESULTS The main radiotherapy technique used consisted in VMAT and IGRT modality.The mainly dose prescription was 55 Gy to high risk volume and 45 Gy as prophylactic volume in 25 fractions given with simultaneous integrated boosts technique(42.85%).The mean pCR was 28.2%with no correlation between dose prescribed and response rates(P value≥0.5).The R0 margins and sphincter preservation rates were 98.88%and 76.03%,respectively.After a mean follow-up of 35 months local control was 92.29%.G3 or higher toxicity was 11.06%with no correlation between dose prescription and toxicities.Patients receiving EQD2 dose>58.9 Gy and BED>70.7 Gy had higher surgical complications rates compared to other group(P value=0.047).CONCLUSION Dose escalation neoadjuvant radiotherapy using innovative techniques is safe for LARC achieving higher rates of pCR.EQD2 doses>58.9 Gy is associated with higher rate of surgical complications.

Radiotherapy for hyoid bone metastasis from lung adenocarcinoma:A case report

BACKGROUND Metastasis to the hyoid bone is an exceptionally rare occurrence,with documented cases limited to breast,liver,colon,skin,lung,and prostate cancers.This report highlights an unusual case involving the metastasis of lung adenocarcinoma to the hyoid bone,accompanied by a distinctive headache.Previous documentation involved surgical resection of the hyoid mass.We present a case displaying the benefits of palliative radiotherapy.CASE SUMMARY A 72-year-old non-smoking,non-alcoholic woman,initially under investigation for a year-long elevation in absolute lymphocyte count,presented with a monthlong history of intermittent throat pain.Despite negative findings in gastroenterological and otolaryngologic examinations,a contrast-enhanced chest computed tomography scan revealed a mediastinal mass and questionable soft tissue thickening in her left anterolateral neck.Subsequent imaging and biopsies confirmed the presence of lung adenocarcinoma metastasis to the hyoid bone.The patient was treated with platinum-based chemo-immunotherapy along with pembrolizumab.Ultimately,the lung cancer was unresponsive.Our patient opted for palliative radiation therapy instead of surgical resection to address her throat pain.As a result,her throat pain was alleviated,and it also incidentally resolved her chronic headaches.This is the second documented case of lung adenocarcinoma metastasizing to the hyoid bone.CONCLUSION Palliative radiotherapy may add to the quality of life in symptomatic patients with cancer metastatic to the hyoid bone.

Correlation between dose-volume parameters and rectal bleeding after 12 fractions of carbon ion radiotherapy for prostate cancer

BACKGROUND Carbon ion radiotherapy(CIRT)is currently used to treat prostate cancer.Rectal bleeding is a major cause of toxicity even with CIRT.However,to date,a correlation between the dose and volume parameters of the 12 fractions of CIRT for prostate cancer and rectal bleeding has not been shown.Similarly,the clinical risk factors for rectal bleeding were absent after 12 fractions of CIRT.AIM To identify the risk factors for rectal bleeding in 12 fractions of CIRT for prostate cancer.METHODS Among 259 patients who received 51.6 Gy[relative biological effectiveness(RBE)],in 12 fractions of CIRT,15 had grade 1(5.8%)and nine had grade 2 rectal bleeding(3.5%).The dose-volume parameters included the volume(cc)of the rectum irradiated with at least x Gy(RBE)(Vx)and the minimum dose in the most irradiated x cc normal rectal volume(Dx).RESULTS The mean values of D6cc,D2cc,V10 Gy(RBE),V20 Gy(RBE),V30 Gy(RBE),and V40 Gy(RBE)were significantly higher in the patients with rectal bleeding than in those without.The cutoff values were D6cc=34.34 Gy(RBE),D2cc=46.46 Gy(RBE),V10 Gy(RBE)=9.85 cc,V20 Gy(RBE)=7.00 cc,V30 Gy(RBE)=6.91 cc,and V40 Gy(RBE)=4.26 cc.The D2cc,V10 Gy(RBE),and V20 Gy(RBE)cutoff values were significant predictors of grade 2 rectal bleeding.CONCLUSION The above dose-volume parameters may serve as guidelines for preventing rectal bleeding after 12 fractions of CIRT for prostate cancer.

Signal intensity changes of dentate nucleus on plain MR T1WI innasopharyngeal carcinoma patients after radiotherapy andmultiple injections of gadolinium-base contrast agent

Objective To observe changes of plain MR T1WI signal intensity of dentate nucleus in nasopharyngeal carcinoma patients after radiotherapy and multiple times of intravenous injection of gadolinium-based contrast agent(GBCA).Methods Fifty patients with pathologically confirmed nasopharyngeal carcinoma and received intensity-modulated radiotherapy were retrospectively enrolled as the nasopharyngeal carcinoma group,and 50 patients with other malignant tumors and without history of brain radiotherapy were retrospectively enrolled as the control group.All patients received yearly GBCA enhanced MR examinations for the nasopharynx or the head.T1WI signal intensities of the dentate nucleus and the pons on same plane were measured based on images in the year of confirmed diagnosis(recorded as the first year)and in the second to the fifth years.T1WI signal intensity ratio of year i(ranging from 1 to 5)was calculated with values of dentate nucleus divided by values of the pons(ΔSI i),while the percentage of relative changes of year j(ranging from 2 to 5)was calculated withΔSI j compared toΔSI 1(Rchange j).The values of these two parameters were compared,and the correlation ofΔSI and GBCA injection year-time was evaluated within each group.Results No significant difference of gender,age norΔSI 1 was found between groups(all P>0.05).The second to the fifth yearΔSI and Rchange in nasopharyngeal carcinoma group were all higher than those in control group(all P<0.05).Within both groups,ΔSI was positively correlated with GBCA injection year-time(both P<0.05).Conclusion Patients with nasopharyngeal carcinoma who underwent radiotherapy and multiple times of intravenous injection of GBCA tended to be found with gradually worsening GBCA deposition in dentate nucleus,for which radiotherapy might be a risk factor.

Prognosis of radiotherapy for esophageal cancer in elderly patients exceeding seventy-five years old

BACKGROUND Esophageal cancer(EC)often occurs in the elderly,with approximately 33%of patients aged≥75 years at the time of diagnosis.AIM To evaluate the prognostic factors for radiotherapy(RT)in elderly patients with unresectable EC.METHODS We retrospectively analyzed the clinical characteristics,toxic reactions,and survival information of EC patients aged≥75 years who underwent intensity-modulated RT at Lu’an Hospital of Anhui Medical University between January 2016 and September 2023.Kaplan-Meier analysis was used to draw the overall survival(OS)curves,and Cox regression analysis was employed to evaluate the influence of various clinical factors on the prognosis.RESULTS A total of 139 patients were enrolled.The median follow-up time was 52.0 months.The median OS was 20.0 months.The 1-year,2-year,3-year,and 5-year OS rates were 69.8%,38.7%,28.2%,and 17.5%,respectively.Univariate analysis showed that age,radiation dose,and chemotherapy had no significant impact on prognosis.Multivariate analysis indicated that clinical stage[Ⅲ-Ⅳa vsⅠ-Ⅱ,hazard ratio(HR)=2.421,95%confidence interval(CI):1.242-4.718,P=0.009;IVb vsⅠ-Ⅱ,HR=4.222,95%CI:1.888-9.438,P<0.001),Charlson comorbidity index(CCI)(0 vs≥1,HR=1.539,95%CI:1.015-2.332,P=0.042),and nutritional risk screening 2002(NRS2002)(<3 vs≥3,HR=2.491,95%CI:1.601-3.875,P<0.001)were independent prognostic factors for OS.CONCLUSION Our results suggest that CCI and NRS2002 were independent prognostic factors of OS for unresectable elderly EC patients undergoing RT.For elderly patients with EC,full attention should be given to biological age-related indicators,such as comorbidities and nutrition,when formulating treatment protocols.These factors should be considered in future clinical practice.

Enhancing Precision in Radiotherapy Delivery: Validating Monte Carlo Simulation Models for 6 MV Elekta Synergy Agility LINAC Photon Beam Using Two Models of the GAMOS Code

The most crucial requirement in radiation therapy treatment planning is a fast and accurate treatment planning system that minimizes damage to healthy tissues surrounding cancer cells. The use of Monte Carlo toolkits has become indispensable for research aimed at precisely determining the dose in radiotherapy. Among the numerous algorithms developed in recent years, the GAMOS code, which utilizes the Geant4 toolkit for Monte Carlo simula-tions, incorporates various electromagnetic physics models and multiple scattering models for simulating particle interactions with matter. This makes it a valuable tool for dose calculations in medical applications and throughout the patient’s volume. The aim of this present work aims to vali-date the GAMOS code for the simulation of a 6 MV photon-beam output from the Elekta Synergy Agility linear accelerator. The simulation involves mod-eling the major components of the accelerator head and the interactions of the radiation beam with a homogeneous water phantom and particle information was collected following the modeling of the phase space. This space was po-sitioned under the X and Y jaws, utilizing three electromagnetic physics mod-els of the GAMOS code: Standard, Penelope, and Low-Energy, along with three multiple scattering models: Goudsmit-Saunderson, Urban, and Wentzel-VI. The obtained phase space file was used as a particle source to simulate dose distributions (depth-dose and dose profile) for field sizes of 5 × 5 cm2 and 10 × 10 cm2 at depths of 10 cm and 20 cm in a water phantom, with a source-surface distance (SSD) of 90 cm from the target. We compared the three electromagnetic physics models and the three multiple scattering mod-els of the GAMOS code to experimental results. Validation of our results was performed using the gamma index, with an acceptability criterion of 3% for the dose difference (DD) and 3 mm for the distance-to-agreement (DTA). We achieved agreements of 94% and 96%, respectively, between simulation and experimentation for the three electromagnetic physics models and three mul-tiple scattering models, for field sizes of 5 × 5 cm2 and 10 × 10 cm2 for depth-dose curves. For dose profile curves, a good agreement of 100% was found between simulation and experimentation for the three electromagnetic physics models, as well as for the three multiple scattering models for a field size of 5 × 5 cm2 at 10 cm and 20 cm depths. For a field size of 10 × 10 cm2, the Penelope model dominated with 98% for 10 cm, along with the three multiple scattering models. The Penelope model and the Standard model, along with the three multiple scattering models, dominated with 100% for 20 cm. Our study, which compared these different GAMOS code models, can be crucial for enhancing the accuracy and quality of radiotherapy, contributing to more effective patient treatment. Our research compares various electro-magnetic physics models and multiple scattering models with experimental measurements, enabling us to choose the models that produce the most reli-able results, thereby directly impacting the quality of simulations. This en-hances confidence in using these models for treatment planning. Our re-search consistently contributes to the progress of Monte Carlo simulation techniques in radiation therapy, enriching the scientific literature.

Evaluation of Air-Kerma and Absorbed Dose to Water for External Radiotherapy Beam Using Ionization Chamber

Radiotherapy is the most widely applied oncologic treatment modality utilizing ionizing radiation. A high degree of accuracy, reliability and reproducibility is required for a successful treatment outcome. Measurement using ionization chamber is a prerequisite for absorbed dose determination for external beam radiotherapy. Calibration coefficient is expressed in terms of air kerma and absorbed dose to water traceable to Secondary Standards Dosimetry Laboratory. The objective of this work was to evaluate the level of accuracy of ionization chamber used for clinical radiotherapy beam determination. Measurement and accuracy determination were carried out according to IAEA TRS 398 protocol. Clinical farmers type ionization chamber measurement and National Reference standard from Secondary Standards Dosimetry Laboratory were both exposed to cobalt-60 beam and measurement results compared under the same environmental conditions. The accuracy level between National Reference Standard and clinical radiotherapy standard was found to be −1.92% and −2.02% for air kerma and absorbed dose to water respectively. To minimize the effect of error and maximize therapeutic dose during treatment in order to achieve required clinical outcome, calibration factor was determined for air kerma (Nk) as 49.7 mGy/nC and absorbed dose to water ND, as 52.9 mGy/nC. The study established that radiotherapy beam measurement chain is prone to errors. Hence there is a need to independently verify the accuracy of radiation dose to ensure precision of dose delivery. The errors must be accounted for during clinical planning by factoring in calibration factor to minimize the systematic errors during treatment, and thereby providing enough room to achieve ±5% dose delivery to tumor target as recommended by ICRU.

Efficacy and Safety of Primary Radiotherapy in Combination with EGFR-TKIs for Non-Small Cell Lung Cancer Harboring EGFR Mutation

Objective: To evaluate the efficacy and safety of EGFR-TKI with the radiotherapy in EGFR mutant metastatic NSCLC. Methods: Retrospective analysis of 72 patients with stage IV lung cancer with EGFR-sensitive mutation. Patients in the A group were treated with the first-generation EGFR-TKI (Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor) combined with radiotherapy for primary tumors (34 cases). The B group was treated with the first-generation EGFR-TKI alone until the disease progressed (38 cases). PFS, OS, pulmonary infection and hematological toxicity during treatment were commented in both groups. Results: The objective remission rate was 47.1% (16/34) in the A group and 21.1% (8/38) in the B group. There was a significant difference between the two groups. There was no significant difference in hematological toxicity between the A group and the B group. There were 10 patients (29.4%) with degree II pulmonary infection in the A group and 3 patients (7.9%) in the B group. The difference between the two groups was statistically significant, suggesting that the incidence of pneumonia in the A group was higher than that in the B group. The median PFS (Progression-Free Survival)) and OS (Overall Survival) of the A group were significantly longer than those of the B group (16.5 months vs 9 months) and the median OS (36 months vs 19 months). The PFS and OS in the A group were significantly longer than those in the B group. Conclusion: EGFR-TKI combined with primary radiotherapy can significantly prolong the drug resistance time of EGFR mutant metastatic NSCLC.