Unraveling the efficacy network: A network meta-analysis of adjuvant external beam radiation therapy methods after hepatectomy

BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent recurrence after liver cancer resection.However,there are multiple RT techniques available,and the differ-ential effects of these techniques in preventing postoperative liver cancer re-currence require further investigation.AIM To assess the advantages and disadvantages of various adjuvant external RT methods after liver resection based on overall survival(OS)and disease-free survival(DFS)and to determine the optimal strategy.METHODS This study involved network meta-analyses and followed the PRISMA guidelines.The data of qualified studies published before July 10,2023,were collected from PubMed,Embase,the Web of Science,and the Cochrane Library.We included relevant studies on postoperative external beam RT after liver resection that had OS and DFS as the primary endpoints.The magnitudes of the effects were determined using risk ratios with 95%confidential intervals.The results were analyzed using R software and STATA software.RESULTS A total of 12 studies,including 1265 patients with hepatocellular carcinoma(HCC)after liver resection,were included in this study.There was no significant heterogeneity in the direct paired comparisons,and there were no significant differences in the inclusion or exclusion criteria,intervention measures,or outcome indicators,meeting the assumptions of heterogeneity and transitivity.OS analysis revealed that patients who underwent stereotactic body radiotherapy(SBRT)after resection had longer OS than those who underwent intensity modulated radiotherapy(IMRT)or 3-dimensional conformal RT(3D-CRT).DFS analysis revealed that patients who underwent 3D-CRT after resection had the longest DFS.Patients who underwent IMRT after resection had longer OS than those who underwent 3D-CRT and longer DFS than those who underwent SBRT.CONCLUSION HCC patients who undergo liver cancer resection must consider distinct advantages and disadvantages when choosing between SBRT and 3D-CRT.IMRT,a RT technique that is associated with longer OS than 3D-CRT and longer DFS than SBRT,may be a preferred option.

The feasibility and safety of high-intensity focused ultrasound combined with low-dose external beam radiotherapy as supplemental therapy for advanced prostate cancer following hormonal therapy

The aim of this study was to investigate the feasibility and safety of high-intensity focused ultrasound （HIFU） combined with （＋） low-dose external beam radiotherapy （LRT） as supplemental therapy for advanced prostate cancer （PCa） following hormonal therapy （HT）. Our definition of HIFU＋LRT refers to treating primary tumour lesions with HIFU in place of reduced field boost irradiation to the prostate, while retaining four-field box irradiation to the pelvis in conventional-dose external beam radiotherapy （CRT）. We performed a prospective, controlled and non-randomized study on 120 patients with advanced PCa after HT who received HIFU, CRT, HIFU＋LRT and HT alone, respectively. CT/MR imaging showed the primary tumours and pelvic lymph node metastases visibly shrank or even disappeared after HIFU ＋LRT treatment. There were significant differences among four groups with regard to overall survival （OS） and disease-specific survival （DSS） curves （P=0.018 and 0.015）. Further comparison between each pair of groups suggested that the long-term DSS of the H IFU ＋ LRT group was higher than those of the other three groups, but there was no significant difference between the HIFU＋LRT group and the CRT group. Multivariable Cox＇s proportional hazard model showed that both HIFU＋LRT and CRT were independently associated with DSS （P=0.001 and 0.035） and had protective effects with regard to the risk of death. Compared with CRT, HIFU ＋LRT significantly decreased incidences of radiation-related late gastrointestinal （GI） and genitourinary （GU） toxicity grade ≥ II. In conclusion, long-term survival of patients with advanced PCa benefited from strengthening local control of primary tumour and reRional lymph node metastases after HT. As an alternative to CRT, HIFU＋LRT showed Rood efficacy and better safety.

Real-time dosimetry in external beam radiation therapy

With growing complexity in radiotherapy treatment delivery,it has become mandatory to check each and every treatment plan before implementing clinically.This process is currently administered by an independent secondary check of all treatment parameters and as a pre-treatment quality assurance (QA) check for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy treatment plans.Although pre-treatment IMRT QA is aimed to ensure the correct dose is delivered to the patient,it does not necessarily predict the clinically relevant patient dose errors.During radiotherapy,treatment uncertainties can affect tumor control and may increase complications to surrounding normal tissues.To combat this,image guided radiotherapy is employed to help ensure the plan conditions are mimicked on the treatment machine.However,it does not provide information on actual delivered dose to the tumor volume.Knowledge of actual dose delivered during treatment aid in confirming the prescribed dose and also to replan/reassess the treatment in situations where the planned dose is not delivered as expected by the treating physician.Major accidents in radiotherapy would have been averted if real time dosimetry is incorporated as part of the routine radiotherapy procedure.Of late real-time dosimetry is becoming popular with complex treatments in radiotherapy.Realtime dosimetry can be either in the form of point doses or planar doses or projected on to a 3D image dataset to obtain volumetric dose.They either provide entrance dose or exit dose or dose inside the natural cavities of a patient.In external beam radiotherapy,there are four different established platforms whereby the delivered dose information can be obtained:(1)Collimator;(2)Patient;(3)Couch;and(4)Electronic Portal Imaging Device.Current real-time dosimetric techniques available in radiotherapy have their own advantages and disadvantages and a combination of one or more of these methods provide vital information about the actual dose delivered to radiotherapy patients.

Dose escalation of external beam radiotherapy for high-risk prostate cancerdImpact of multiple high-risk factor

Objective:To retrospectively investigate the treatment outcomes of external beam radiotherapy with androgen deprivation therapy(ADT)in high-risk prostate cancer in three radiotherapy dose groups.Methods:Between 1998 and 2013,patients with high-risk prostate cancer underwent threedimensional conformal radiotherapy or intensity-modulated radiotherapy of 66 Gy,72 Gy,or 78 Gy with ADT.Prostate-specific antigen(PSA)relapse was defined using the Phoenix definition.PSA relapse-free survival(PRFS)was evaluated in each radiotherapy dose group.Moreover,high-risk patients were divided into H-1(patients with multiple high-risk factors)and H-2(patients with a single high-risk factor)as risk subgroups.Results:Two hundred and eighty-nine patients with a median follow-up period of 77.3 months were analyzed in this study.The median duration of ADT was 10.1 months.Age,Gleason score,T stage,and radiotherapy dose influenced PRFS with statistical significance both in univariate and multivariate analyses.The 4-year PRFS rates in Group-66 Gy,Group-72 Gy and Group-78 Gy were 72.7%,81.6%and 90.3%,respectively.PRFS rates in the H-1 subgroup differed with statistical significance with an increasing radiotherapy dose having a more favorable PRFS,while PRFS rates in H-2 subgroup did not differ with increase in radiotherapy dose.Conclusion:Dose escalation for high-risk prostate cancer in combination with ADT improved PRFS.PRFS for patients in the H-1 subgroup was poor,but dose escalation in those patients was beneficial,while dose escalation in the H-2 subgroup was not proven to be effective for improving PRFS.

Adjuvant External Beam Radiotherapy ±Brachytherapy in Endometrial Cancer: A Retrospective Study from Faculty of Medicine, Chiang Mai University

Purpose: To report the retrospective study of external beam radiotherapy (EBRT) ± intravaginal brachytherapy (IVBT) as adjuvant treatment for endometrial cancer. Materials and Methods: From 2001-2009, 152 patients received complete surgical staging for endometrial carcinoma and were designed by a multidisciplinary team to receive EBRT ± IVBT. The treatment results and late toxicities were evaluated and recorded. Results: At the median follow-up time of 43 months, the disease-free survival, metastasis-free survival and overall survival rates were 96.9%, 96.9% and 96.9%, respectively. Stage and age showed the statistical significance with the p-value of less than 0.001. From five to ten percent of patients developed Grades 1-2 late gastrointestinal and genitourinary toxicities, respectively. Conclusion: The using of adjuvant EBRT ± IVBT for endometrial?carcinoma yielded treatment results and acceptable toxicities.

Linear Accelerator Based External Beam Radiotherapy in Glomus Jugulare Tumour: A Retrospective Review from a Tertiary Cancer Hospital in Kenya

Objective: Tumours originating from jugular bulb, carotid bifurcation, Vagus nerve are collectively called Paragangliomas. They are slow growing, essentially benign tumours, but can be detrimental if untreated. There is limited evidence on the effectiveness of fractionated radiotherapy in the management ofs Glomus jugulare tumours. The aim of this study is to determine the efficacy of Linear accelerator based fractionated external beam radiotherapy on unilateral inoperable Glomus jugulare paragangliomas. Method: This is a retrospective analysis of all the 12 cases of inoperable, unilateral Glomus jugulare tumours treated during the period 2011-2016 at a tertiary cancer centre in Kenya. Minimum follow up duration was 3 years. Patient characteristics, disease staging, immediate complications and therapeutic efficacy were analysed from the case files. Results: The 12 patients diagnosed with inoperable Glomus jugulare tumours reported in this period were treated with external beam radiotherapy to a tumour dose of 54 Gy in 30 fractions over a period of 6 weeks using IMRT technique in 6 MV Linear accelerator. 2/3rd of the patients were females in 5th and 6th decade of life. Onset of first symptom to initiation of treatment was found to be 1.7 years. Headache, earache, and tinnitus were the main complaints. No major side effects were recorded during therapy. Mean length of the tumour in its maximum dimension at the time of diagnosis was 4.5 cm. At the end of one-year post therapy, a mean reduction of 6.5 mm in the tumour length was observed, (Range: 0 - 15 mm). Tumour size remained static for a year and thereafter a slow growth pattern of 1mm per year was observed. Conclusion: Fractionated external beam radiotherapy is an effective and non-invasive treatment for advanced, inoperable Glomus jugulare paragangliomas. Clinical stability through tumour control was observed. Though newer radiation techniques like Cyberknife, Proton therapy offer better tumour control, conventional external beam radiotherapy is an effective tool in disease containment in resource limited countries.

Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) treatment of cervical cancer. Materials and Methods: A study of QA verification of target doses of 198 cervical cancer patients undergoing External Beam Radiotherapy (EBRT) treatments at two different cancer treatment centers in Kenya was conducted. The target doses were determined from measured entrance doses by the diode in vivo dosimetry. Process Behavior Charts (PBC) developed by SPC were applied for setting Action Thresholds (AT) on the target doses. The AT set was then proposed as QA limits for acceptance or rejection of verified target doses overtime of the EBRT process. Result and Discussion: Target doses for the 198 patients were calculated and SPC applied to test whether the action limits set by the Process Behavior Charts could be applied as QA for verified doses in EBRT. Results for the two sub-groups of n = 3 and n = 4 that were tested produced action thresholds which are within clinical dose specifications for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. Conclusion: Action thresholds set by SPC were within the clinical dose specification of ±5% uncertainty for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. So the concept of SPC could be applied in setting QA action limits for dose verifications in EBRT.

Combined cryotherapy and external beam radiation therapy for the treatment of intermediate-risk localized prostate cancer: A case series

Introduction: Routine PSA screening for prostate cancer (PCa) has increased the detection of intermediate-risk, localized disease. Conventional treatments for localized PCa include surgery, brachytherapy, cryotherapy or external beam radiotherapy (EBRT). However, for intermediate risk patients, rates of recurrence are moderately high and a multi-modal treatment approach for these patients may be necessary. We treated patients with a combination of cryotherapy and low dose EBRT to assess the safety and feasibility of this combinatory approach as well as to evaluate early oncological outcomes. Case Presentation: Men with intermediate risk (PSA = 10-20 ng/ml and/or Gleason = 7 and/or clinical T2b) localized PCa were prospectively enrolled in this study. Patients underwent cryotherapy and then 39 Gy EBRT 4-6 weeks after surgery. After completing EBRT, the men were followed every 3 months for 2 years. Adverse events, PSA, urinary and erectile function were assessed during each follow-up. Three patients completed the study. Preoperative PSA ranged from 3.5 to 7.9 ng/ml. There were no intraoperative complications and the treatment was well tolerated. Following cryotherapy and EBRT, all patients were pad-free within 6 months and remained continent for the duration of the study. Bother index remained stable throughout the study for all patients. No urethral strictures or rectal toxicities were observed. PSA remained undetectable for all patients. Conclusions: In this prospective study, cryotherapy combined with low dose EBRT was a safe approach for the treatment of intermediate-risk, localized PCa. Early oncological outcomes appeared to be favorable with all patients having undetectable PSA during the 2-year follow-up period. Further studies are warranted to confirm these preliminary results.

Californium-252 neutron brachytherapy combined with external pelvic radiotherapy plus concurrent chemotherapy for cervical cancer: a retrospective clinical study

Background:Cervical cancer is the sixth most common cancer in Chinese women.A standard treatment modal?ity for cervical cancer is the combination of surgery,chemotherapy,external?beam radiotherapy and intracavitary brachytherapy.The aim of this study was to retrospectively assess the long?term treatment outcomes of patients with cervical cancer who were treated with californium?252 neutron brachytherapy combined with external?beam radio?therapy plus concurrent chemotherapy.Methods:We retrospectively analyzed the medical records of 150 patients with primary stages IB?IVB cervical cancer who received neutron brachytherapy combined with external?beam radiotherapy concurrently with cisplatin chemo?therapy.All patients were followed up.Using an actuarial analysis,patient outcomes and treatment?related adverse effects were evaluated and compared.Results:The median overall survival(OS)was 33.2 months.The 3?year progression?free survival rates for patients with stages I–II,III,and IV diseases were 81.0%(68/84),65.0%(39/60),and 0%(0/6),respectively;the 3?year OS rates were 90.5%(76/84),85.0%(51/60),and 16.7%(1/6),respectively.Vaginal bleeding was controlled within the median time of4.0 days.One month after treatment,97.3%of patients achieved short?term local control.The local recurrence rates for patients with stages I–II,III,and IV disease were 4.8%(4/84),11.7%(7/60),and 33.3%(2/6),respectively,and the occurrence rates of distant metastasis were 16.7%(14/84),25.0%(15/60),and 100.0%(6/6),respectively.Cancer stage,tumor size,and lymph node metastasis were identified as prognostic risk factors,but only lymph node metastasis was found to be an independent prognostic factor.The most common adverse effects during treatment were grades 1 and 2 irradiation?related proctitis and radiocystitis.Conclusion:For patients with cervical cancer,neutron brachytherapy combined with external?beam radiotherapy plus concurrent chemotherapy produces a rapid response and greatly improves local control and long?term survival rates with tolerable adverse effects.

Efficacy and safety of intraoperative radiotherapy in rectal cancer:A systematic review and meta-analysis

BACKGROUND In recent years,intraoperative radiotherapy(IORT)has been increasingly used for the treatment of rectal cancer.However,the efficacy and safety of IORT for the treatment of rectal cancer are still controversial.AIM To evaluate the value of IORT for patients with rectal cancer.METHODS We searched PubMed,Embase,Cochrane Library,Web of Science databases,and conference abstracts and included randomized controlled trials and observational studies on IORT vs non-IORT for rectal cancer.Dichotomous variables were evaluated by odds ratio(OR)and 95%confidence interval(CI),hazard ratio(HR)and 95%CI was used as a summary statistic of survival outcomes.Statistical analyses were performed using Stata V.15.0 and Review Manager 5.3 software.RESULTS In this study,3 randomized controlled studies and 12 observational studies were included with a total of 1460 patients,who are mainly residents of Europe,the United States,and Asia.Our results did not show significant differences in 5-year overall survival(HR=0.80,95%CI=0.60-1.06;P=0.126);5-year disease-free survival(HR=0.94,95%CI=0.73-1.22;P=0.650);abscess(OR=1.10,95%CI=0.67-1.80;P=0.713),fistulae(OR=0.79,95%CI=0.33-1.89;P=0.600);wound complication(OR=1.21,95%CI=0.62-2.36;P=0.575);anastomotic leakage(OR=1.09,95%CI=0.59-2.02;P=0.775);and neurogenic bladder dysfunction(OR=0.69,95%CI=0.31-1.55;P=0.369).However,the meta-analysis of 5-year local control was significantly different(OR=3.07,95%CI=1.66-5.66;P=0.000).CONCLUSION The advantage of IORT is mainly reflected in 5-year local control,but it is not statistically significant for 5-year overall survival,5-year disease-free survival,and complications.

Current role of spacers for prostate cancer radiotherapy

Radiotherapy is an established curative treatment method for prostate cancer. Optimal tumor control rates can only be achieved with high local doses,associated with a considerable risk of rectal toxicity. Apart from already widely adapted technical advances,as intensitymodulated radiation therapy,the application of spacers placed between the prostate and rectum has been increasingly used in the last years. Biodegradable spacers,including hydrogel,hyaluronic acid,collagen or an implantable balloon,can be injected or inserted in a short procedure under transrectal ultrasound guidance via a transperineal approach. A distance of about 1.0-1.5 cm is usually achieved between the rectum and prostate,excluding the rectal wall from the high isodoses. Several studies have shown well tolerated injection procedures and treatments. Apart from considerable reduction of rectal irradiation,a prospective randomized trial demonstrated a reduction of rectal toxicity after hydrogel injection in men undergoing prostate image-guided intensity-modulated radiation therapy. The results are encouraging for continuing evaluation in dose escalation,hypofractionation,stereotactic radiotherapy or re-irradiation trials in the future.

A Longitudinal Study of Clinical Benefits with Implementation of the Deep Inspiration Breath-Hold Technique in Post-Operative Radiotherapy for Left-Sided Breast Cancer

Purpose/Objectives: We aimed to report clinical effects on critical organ dose and cardiac toxicity from implementation of the deep inspiration breath-hold (DIBH) technique in post-operative extern-beam radiotherapy of patients with left-sided breast cancer, using longitudinal clinical data. Materials/Methods: We retrieved three groups of patients who received post-operative radiotherapy of left-sided breast cancer in our institution in recent years: Groups A and B consist of patients whose treatment did not include internal mammary nodes (IMN) and who were treated with the free breathing technique and with the DIBH technique, respectively, and Group C consists of patients whose radiotherapy included internal mammary nodes with the DIBH technique. Dose parameters for the heart and left lung were retrieved from the treatment plans. Radiation-induced cardiac risks were estimated using existing risk models. Results: The average heart dose was 2.65 ± 0.98 Gy, 1.10 ± 0.29 Gy, and 1.26 ± 0.25 Gy in Groups A, B, and C, respectively. The average heart volumes receiving at least 25 Gy were 7.10 ± 9.79 cc in Group A, 0.07 ± 0.22 cc in Group B, and 0.03 ± 0.08 cc in Group C. On average, the excessive risk of having ischemic heart disease was estimated to be 19.6%, 8.1%, and 9.3% in Groups A, B, and C, respectively. The mean left lung doses were 5.73 ± 1.86 Gy, 5.93 ± 1.55 Gy, and 9.13 ± 1.57 Gy in Groups A, B, and C, respectively. Conclusion: Implementation of the DIBH technique significantly lowered heart dose and decreased the ischemic heart disease risk in patients receiving post-operative radiotherapy for left-sided breast cancer, without significant increase in left lung dose.

Outcomes of External-Beam Radiation Therapy Boost with Conventional Fractionation in Cervical Cancer: A Retrospective Analysis about 133 Cases

Introduction: External-beam radiation therapy boost is a treatment option in cervical cancer when brachytherapy is not feasible. Though less effective than brachytherapy, some encouraging results have been reported from some institutions experiences. We conducted this study to assess outcomes of EBRT boost for our patients at National Institute of Oncology in Rabat. Patients and Methods: We collected data from patients treated for cervical cancer between January 2012 and December 2015. Patients, tumor and treatment characteristics were collected. Overall survival (OS), disease-free survival (DFS) and prognostic factors influencing DFS were assessed. Results: One hundred and thirty-three patients were enrolled. Median age was 52 years. Patient haemoglobin level ranged from 3.9 to 15.5 g/dl [mean: 11.2 g/dl]. Most tumors were classified stage III/IVA (63.2%) according to the FIGO classification. Regional lymph node metastases (pelvic and or para-aortic) were observed in 45.1%. Median total dose to tumor was 69.6 Gy (ranging from 66 to 70 Gy). Overall treatment time was protracted, with a median of 60 days. Most of patients received concurrent chemotherapy (94.7%) and the number of cycle ranged from 2 to 7 (median = 5). The follow-up median was 31.3 months, ranging from 6.2 to 96.8 months. At the first visit, most patients achieved complete response (80.5%). Five years OS and DFS were 47% and 44% respectively. In univariate and multivariate analysis, regional lymph nodes metastasis (presence or absence) and haemoglobin level (≤11 g/dl and >11 g/dl) were the two significant and independent prognostic factors influencing DFS (HR: 1.86;p = 0.01 for the former) (HR: 0.59;p = 0.03 for the latter). Conclusion: Our study showed that EBRT boost in conventional fractionation was an acceptable treatment option for cervical cancer unamenable to brachytherapy, especially in the two subgroups of patients that are those without pelvic and/or para-aortic lymph node metastasis and those with haemoglobin level above 11 g/dl.

Radiation Oncology and Medical Devices( Part 1)

Modern radiation treatments have become fairly complex and involve in utilizing a variety of medical devices to achieve the goal of providing conformal radiation dose coverage to the tumor target(s)while maximizing the sparing of normal organ structures.Recently,different forms of linear accelerators/radioactive source based machines have been invented and developed with the aim of providing improved treatments and more treatment options.Besides linear accelerators(Linac)that have been undergoing constant improvement and advancement and can deliver fairly complicated dose distribution patterns,imaging systems,computer information and calculation systems have been more and more integrated into radiotherapy processes.To bring radiotherapy to a potentially higher level,many institutions have either acquired or started to consider particle therapy,especially proton therapy.The complexity of modern radiotherapy demands in-depth understanding of radiation physics and machine engineering as well as computer information systems.This paper is intended to provide an introductory description of radiation oncology and related procedures,and to provide an overview of the current status of medical devices in radiotherapy in the United States of America.This paper covers the radiation delivery systems,imaging systems,treatment planning systems,record and verify systems,and QA systems.

Radiation Oncology and Medical Devices(Part 2)

Radiation oncology is one of the three major treatment modalities to manage cancer patient cares,and is a discipline mainly driven by technology and medical devices.Modern radiation treatments have become fairly complex and involve in utilizing a variety of medical devices to achieve the goal of providing conformal radiation dose coverage to the tumor target(s)while maximizing the sparing of normal organ structures.Recently,different forms of linear accelerators/radioactive source based machines have been invented and developed with the aim of providing improved treatments and more treatment options.Besides linear accelerators(Linac)that have been undergoing constant improvement and advancement and can deliver fairly complicated dose distribution patterns,imaging systems,computer information and calculation systems have been more and more integrated into radiotherapy processes.To bring radiotherapy to a potentially higher level,many institutions have either acquired or started to consider particle therapy,especially proton therapy.The complexity of modern radiotherapy demands in-depth understanding of radiation physics and machine engineering as well as computer information systems.This paper is intended to provide an introductory description of radiation oncology and related procedures,and to provide an overview of the current status of medical devices in radiotherapy in the United States of America.This paper covers the radiation delivery systems,imaging systems,treatment planning systems,record and verify systems,and QA systems.

Nanoparticles for targeted cancer radiotherapy

Radiotherapy,where ionizing radiation is locally delivered either through an external beam or by surgically implanting radionuclide-based seeds in the tumor,is one of the gold standard treatments for cancer.Due to the non-selective nature of radiation,healthy tissue surrounding the cancerous region is usually affected by the treatment.Hence,new strategies,including targeted alpha therapy,are being studied to improve the selectivity of the treatment and minimize side effects.Several challenges,however,limit the current development of targeted radiotherapy,such as the functionalization of the therapeutic agent with targeting vectors and controlling the release of recoiling daughters.Nanoparticles offer unique opportunities as drug delivery vehicles,since they are biocompatible,enhance the cellular uptake of drugs,and are easily functionalized with targeting molecules.In this review,we examine how nanoparticles can be used for targeted radiotherapy,either as sensitizers of external beams or as delivery vehicles for therapeutic radionuclides.We describe the clinical relevance of different types of nanoparticles,followed by an analysis of how these nanoconstructs can solve some of the main limitations of conventional radiotherapy.Finally,we critically discuss the current situation of nanoparticle-based radiotherapy in clinical settings and challenges that need to be overcome in the future for further development of the field.

Radiotherapy and the cellular DNA damage response: current and future perspectives on head and neck cancer treatment

Incidences of head and neck squamous cell carcinoma(HNSCC)have been on the rise in the last few decades,with a significant risk factor being human papillomavirus(HPV)type-16/18 infection,particularly in the development of oropharyngeal cancers.Radiotherapy(RT)is an important treatment modality for HNSCC,where it promotes extensive cellular DNA damage leading to the therapeutic effect.It has been well-established that HPV-positive HNSCC display better response rates and improved survival following RT compared to HPV-negative HNSCC.The differential radiosensitivity has been largely associated with altered cellular DNA damage response mechanisms in HPV-positive HNSCC,and particularly with the signaling and repair of DNA double strand breaks.However,other factors,particularly hypoxia present within the solid cancer,have a major impact on relative radioresistance.Consequently,recent approaches aimed at enhancing the radiosensitivity of HNSCC have largely centered on targeting key proteins involved in DNA repair,DNA damage checkpoint activation,and hypoxia signaling.These studies have utilised in vitro and in vivo models of HPV-positive and HPV-negative HNSCC and examined the impact of specific inhibitors against the targets in combination with radiation in suppressing HNSCC cell growth and survival.Here,accumulating evidence has shown that targeting enzymes including poly(ADP-ribose)polymerase,ataxia telangiectasia and Rad-3 related,DNA-dependent protein kinase catalytic subunit,and checkpoint kinase 1 can radiosensitise HNSCC cells which should be taken forward in further preclinical studies,with the goal of optimizing the future effective RT treatment of HNSCC.

Improving patient care and accuracy of given doses in radiation therapy using in vivo dosimetry verification

Objective This work aims to verify and improve the dose given for cancer patients in radiation therapy by using diodes to enhance patient in vivo dosimetry on a routine basis. Some characteristics of two available semi-conductor diode dosimetry systems were evaluated. Methods The diodes had been calibrated to read the dose at Dmax below the surface. Correction factors of clinical relevance were quantified to convert the diode readings into patient dose. The diode was irradiated at various gantry angles （increments of 45~）, various Field Sizes and various Source to Surface Distances （SSDs）. Results The maximal response variation in the angular response with respect to an arbitrary angle of 0~ was 1.9%, and the minimum variation was 0.5%. The response of the diode with respect to various field siz- es showed the minimum and the maximum variations in the measured dose from the diode; the calculated doses were -1.6% （for 5 cm x 5 cm field size） and 6.6% （for 40 cm x 40 cm field size）. The diode exhibited a significant perturbation in the response, which decreased with increasing SSD. No discrepancies larger than 5% were detected between the expected dose and the measured dose. Conclusion The results indicate that the diodes exhibit excellent linearity, dose reproducibility and minimal anisotropy; that they can be used with confidence for patient dose verification. Furthermore, diodes render real time verification of the dose delivered to patients.

根治性前列腺切除术、外照射、前列腺近距离放射治疗对前列腺癌患者性功能的影响

目的对比分析根治性前列腺切除术、外照射、前列腺近距离放射治疗对前列腺癌患者性功能的影响。方法筛选2020年1月-2022年12月吉安市中心人民医院泌尿外科收治的80例前列腺癌患者进行回顾性分析。根据治疗方案将其分为手术切除组(n=26,行根治性前列腺切除术)、外照射组(n=28,使用高能量的X射线或粒子束从体外直接照射肿瘤细胞)与近距放射组(n=26,在前列腺内直接放置放射性物质作用于癌细胞)。统计各组患者年龄、体重指数(BMI)、格里森评分等一般资料。使用国际勃起功能指数(IIEF)量表评估患者勃起功能障碍,性功能障碍指数(SDI)量表评估患者性欲水平,男性性功能问卷(MSHQ)评估患者性功能。治疗结束后6个月,使用焦虑自评量表(SAS)和抑郁自评量表(SDS)评估患者焦虑、抑郁情况。结果各组年龄、BMI、格里森评分等一般资料比较差异均无统计学意义(P>0.05)。近距放射组勃起功能无障碍率较手术切除组和外照射组增高(P<0.05),勃起功能轻度障碍和中重度障碍率较手术切除组降低(P<0.05);外照射组勃起无障碍率较手术切除组增高(P<0.05),勃起中重度障碍率较手术切除组降低(P<0.05)。近距放射组性幻想、性欲、性频率评分和SDI总评分较手术切除组和外照射组增高(P<0.05),外照射组性幻想、性欲、性频率评分和SDI总评分较手术切除组增高(P<0.05)。近距放射组性功能总评分较手术切除组和外照射组增高(P<0.05),外照射组性功能总评分较手术切除组增高(P<0.05)。近距放射组SAS、SDS评分均较手术切除组和外照射组降低(P<0.05)。结论在前列腺癌治疗方法中,前列腺近距离放射治疗在保持性功能方面相对更有效,尤其是在勃起功能和性欲方面的表现优于根治性前列腺切除术和外照射治疗。

鼻咽癌放疗头颈部摆位误差及外轮廓变化对放疗剂量的影响

目的:采用千伏级锥形束CT(CBCT)获取分次间鼻咽癌调强放疗中的外轮廓变化及摆位误差,分析其对靶区及危及器官剂量分布的影响。方法:选取21例鼻咽癌患者,将全部患者的137次CBCT图像与定位CT图像匹配后得到左右、头脚、腹背方向的摆位误差数据。选取颈部3个不同层面,测量其外轮廓横切面宽度,并利用Pearson系数和独立样本t检验分析其对摆位误差的影响。基于CBCT影像制定模拟计划,分析摆位误差和外轮廓变化对放疗剂量的影响,并应用Mann-Whitney秩和检验进行显著性分析。结果:左右、头脚、腹背方向的摆位误差分别为(1.04±0.73)、(1.13±0.87)、(1.38±0.95)mm。A、B、C层面上的头颈部最大外轮廓变化率分别为15.36%、14.94%、14.99%。模拟计划显示GTV D_(98)、CTV1 D_(95)、CTV2 D_(95)靶区的模拟计划的剂量均小于执行的计划剂量,差异有统计学意义(P<0.05);脑干和脊髓的模拟计划D_(max)均大于计划剂量,差异有统计学意义(P<0.05)。结论:通过模拟计划可知,当摆位误差和外轮廓变化等不确定性因素存在时,靶区的剂量变化较大,其中GTV D_(98)最大减小11.49%,CTV1 D_(95)、CTV2 D_(95)最大变化率分别为12.88%、21.64%。除左右晶体和左腮腺之外,其余的危及器官和靶区剂量均有显著性差异,表明实际放疗中摆位误差和外轮廓变化的存在会对剂量分布造成显著影响。