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.

Single-fraction stereotactic ablative body radiation therapy for primary and metastasic lung tumor:A new paradigm?

Stereotactic ablative body radiotherapy(SABR)is an effective technique comparable to surgery in terms of local control and efficacy in early stages of non-small cell lung cancer(NSCLC)and pulmonary metastasis.Several fractionation schemes have proven to be safe and effective,including the single fraction(SF)scheme.SF is an option costeffectiveness,more convenience and comfortable for the patient and flexible in terms of its management combined with systemic treatments.The outbreak of the severe acute respiratory syndrome coronavirus 2 pandemic has driven this not new but underutilized paradigm,recommending this option to minimize patients’visits to hospital.SF SABR already has a long experience,strong evidence and sufficient maturity to reliably evaluate outcomes in peripheral primary NSCLC and there are promising outcomes in pulmonary metastases,making it a valid treatment option;although its use in central locations,synchronous and recurrencies tumors requires more prospective safety and efficacy studies.The SABR radiobiology study,together with the combination with systemic therapies,(targeted therapies and immunotherapy)is a direction of research in both advanced disease and early stages whose future includes SF.

Stereotactic body radiation therapy for non-small cell lung cancer:A review

Stereotactic body radiation therapy(SBRT) is the treatment of choice for medically inoperable patients with early stage non-small cell lung cancer(NSCLC). A literature search primarily based on PubMed electronic databases was completed in July 2018. Inclusion and exclusion criteria were determined prior to the search, and only prospective clinical trials were included. Nineteen trials from 2005 to 2018 met the inclusion criteria, reporting the outcomes of 1434 patients with central and peripheral early stage NSCLC. Patient eligibility,prescription dose and delivery, and follow up duration varied widely. Threeyears overall survival ranged from 43% to 95% with loco-regional control of up to 98% at 3 years. Up to 33% of patients failed distantly after SBRT at 3 years. SBRT was generally well tolerated with 10%-30% grade 3-4 toxicities and a few treatment-related deaths. No differences in outcomes were observed between conventionally fractionated radiation therapy and SBRT, central and peripheral lung tumors, or inoperable and operable patients. SBRT remains a reasonable treatment option for medically inoperable and select operable patients with early stage NSCLC. SBRT has shown excellent local and regional control with toxicity rates equivalent to surgery. Decreasing fractionation schedules have been consistently shown to be both safe and effective. Distant failure is common, and chemotherapy may be considered for select patients. However, the survival benefit of additional interventions, such as chemotherapy, for early stage NSCLC treated with SBRT remains unclear.

Stereotactic radiotherapy for prostate cancer:A review and future directions

Prostate cancer affects over 200000 men annually in the United States alone.The role of conventionally fractionated external beam radiation therapy (RT) is well established as a treatment option for eligible prostate cancer patients; however,the use of stereotactic body radiotherapy (SBRT) in this setting is less well defined.Within the past decade,there have been a number of studies investigating the feasibility of SBRT as a potential treatment option for prostate cancer patients.SBRT has been well studied in other disease sites,and the shortened treatment course would allow for greater convenience for patients.There may also be implications for toxicity as well as disease control.In this review we present a number of prospective and retrospective trials of SBRT in the treatment of prostate cancer.We focus on factors such as biochemical progression-free survival,prostate specific antigen (PSA) response,and toxicity in order to compare SBRT to established treatment modalities.We also discuss future steps that the clinical community can take to further explore this new treatment approach.We conclude that initial studies examining the use of SBRT in the treatment of prostate cancer have demonstrated impressive rates of biochemical recurrencefree survival and PSA response,while maintaining a relatively favorable acute toxicity profile,though long-term follow-up is needed.

Stereotactic radiotherapy for intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma(iCCA)is an aggressive malignancy with an increasing incidence worldwide and poor prognosis,despite several advances and continuous efforts to develop effective treatments.Complete surgical resection is the mainstay of treatment and offers a potentially curative option,but is only possible in less than a third of patients,owing to advanced disease.Chemotherapy is a well-established treatment in the adjuvant and palliative setting,however,confers limited benefit.Conventional radiotherapy is challenging due to local toxicity.With recent advances in stereotactic ablative radiotherapy(SABR),it is now possible to focus ablative beams of radiotherapy precisely aimed at tumours to minimise damage to surrounding viscera.This review details the history,technical background and application of SABR to iCCA,with directions for future research suggested.

Oligometastases in prostate cancer:Ablative treatment

Technological advances in radiotherapy have led to the introduction of techniques such as stereotactic body radiation therapy(SBRT), allowing the administration of ablative doses. The hypothesis that oligometastatic disease may be cured through local eradication therapies has led to the increasing use of SBRT in patients with this type of disease. At the same time, scientific advances are being made to allow the confirmation of clinically suspected oligometastatic status at molecular level. There is growing interest in identifying patients with oligometastatic prostate cancer(PCa) who may benefit from curative intent metastasis-directed therapy, including SBRT. The aim is to complement, replace or delay the introduction of hormone therapy or other systemic therapies. The present review aims to compile the evidence from the main ongoing studies and results on SBRT in relation to oligometastatic PCa; examine aspects where gaps in knowledge or a lack of consensus persist(e.g., optimum schemes, response assessment, identification and diagnosis of oligometastatic patients); and document the lack of first-level evidence supporting the use of such techniques.

立体定向消融放射治疗(SABR)医用直线加速器的相关剂量学研究

目的:研究ELEKTA Synergy加速器SABR临床治疗的相关剂量学特点。方法:根据IAEA TRS277报告(97年版)和《医用电子加速器验收和周期检验规程》(GB/T 19046-2003)相关内容测量ELEKTA Synergy加速器相关剂量指标。对ELEKTA Synergy加速器实施SABR治疗病人的临床治疗计划进行剂量分布验证。结果:ELEKTA Synergy的临床剂量学相关指标符合IAEA TRS277报告(97年版)和《医用电子加速器验收和周期检验规程》(2003年版)的指标要求;临床治疗计划剂量分布的验证满足SABR治疗的临床要求。结论:ELEKTA Synergy加速器剂量相关指标和临床治疗计划剂量分布数据的偏差范围可以满足SABR临床治疗的要求。

Technical advances in external radiotherapy for hepatocellular carcinoma

Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular carcinoma(HCC). Currently, more advanced techniques, including intensity-modulated radiotherapy(IMRT), stereotactic ablative body radiotherapy(SABR), and charged particle therapy, are used for the treatment of HCC. IMRT can escalate the tumor dose while sparing the normal tissue even though the tumor is large or located near critical organs. SABR can deliver a very high radiation dose to small HCCs in a few fractions, leading to high local control rates of 84%-100%. Various advanced imaging modalities are used for radiotherapy planning and delivery to improve the precision of radiotherapy. These advanced techniques enable the delivery of high dose radiotherapy for early to advanced HCCs without increasing the radiation-induced toxicities. However, as there have been no effective tools for the prediction of the response to radiotherapy or recurrences within or outside the radiation field, future studies should focus on selecting the patients who will benefit from radiotherapy.

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.

原发性肝癌立体定向消融放疗后CT影像学随访观察

目的观察原发性肝癌全身γ刀立体定向消融放疗（SABR）后的CT影像学表现。方法随机选取采用超级γ刀（SGS-I型）SABR的肝癌患者100例，将112个可评价病灶按肿瘤大小分为三组：A组，肿瘤最大径〈5cm；B组，肿瘤最大径5—10cm；C组，肿瘤最大径〉10cm。治疗后2—3个月及半年CT复查，分析不同类型和大小肿瘤治疗后的CT平扫及增强影像特点。结果肝癌γ刀治疗后2—3个月CT复查，与治疗前比较，A组病灶缩小不明显，无统计学差异（t=1．51，P〉0．05），B、C组病灶明显缩小，差异有统计学意义（t=10．07、8．56，P均〈0．05）。增强扫描，所有病灶边缘均与治疗靶区形状基本一致，清晰可见。其中27（24．11％）个病灶动脉期及门脉期均无明显强化，30（26．79％）个病灶边缘动脉期出现环形强化，门脉期强化仍可见，但减弱，55（49．11％）个病灶动脉期边缘强化，门脉期强化较动脉期明显，延迟期强化仍可见。治疗半年后所有边缘强化均减弱或消失，变得模糊。结论肝癌γ刀治疗后CT影像表现具有多样性，需结合临床，AFP检查方可作出客观评价。

Management of oligometastatic non-small cell lung cancer patients:Current controversies and future directions

Oligometastatic non-small cell lung cancer(NSCLC)describes an intermediate stage of NSCLC between localized and widely-disseminated disease.This stage of NSCLC is characterized by a limited number of metastases and a more indolent tumor biology.Currently,the management of oligometastatic NSCLC involves radical treatment(radiotherapy or surgery)that targets the metastatic lesions and the primary tumor to achieve disease control.This approach offers the potential to achieve prolonged survival in patients who,in the past,would have only received palliative measures.The optimal therapeutic strategies for the different scenarios of oligometastatic disease(intracranial vs extracranial disease,synchronous vs metachronous)remain undefined.Given the lack of head-to-head studies comparing radiotherapy to surgery in these patients,the decision to apply surgery or radiotherapy(with or without systemic treatment)must be based on prognostic factors that allow us to classify patients.This classification will allow us to select the most appropriate therapeutic strategy on an individualized basis.In the future,the molecular or microRNA profiles will likely improve the treatment selection process.The objective of the present article is to review the most relevant scientific evidence on the management of patients with oligometastatic NSCLC,focusing on the role of radiotherapy and surgery.We also discuss areas of controversy and future directions.

Oligometastatic disease, the curative challenge in radiation oncology

The concept of oligometastatic disease was first described by Hellman and Weichselbaum in 1995. The mere insight of this concept led to the hypothesis that this disease may be cured using local ablative weapons. Surgery has already demonstrated this hypothesis. Surgery limitations, either technical or due to refusalor associated comorbidity, have led to implement alternative ablative options such as stereotactic body radiation therapy(SBRT). SBRT evolved from(stereotactic radiosurgery) because of the need to irradiate extracranial lesions and has been shown to be safe and effective. SBRT achieves local control rates ranging from 70%-90%, but highly variable survival rates depending on the group analyzed. Series with heterogeneous metastatic sites and tumor origin have reported 20% survival rates at 2-3 years, similar to those achieved with surgery. Despite its excellent results, SBRT still faces significant clinical challenges. Its optimal integration with systemic treatment is unknown, and response assessment is very difficult. However, the greatest challenge lies in selection of patients most likely to remain oligometastatic, those who will most benefit from the technique. Biomarkers, molecular signatures, that accurately predict the biological behavior of malignancy are needed. The expression profile of specific mi RNAs has been shown to have a potential in this regard.

必需功能性肝体积评估在孤立性大肝癌γ-立体定向消融放射治疗中的应用研究

随着现代医疗技术的飞速进展,放射治疗在肝癌治疗中占据了重要地位。根据大肝癌的生物学特点、肝癌放射治疗的国内外现状及发展趋势、以及大肝癌立体定向放射治疗技术特征,得出了肝癌放射治疗效果可与手术切除相媲美的结论。γ-立体定向消融放射治疗(γ-SABR)为高度精确的立体定向放射治疗,目前在γ-SABR治疗前,需根据患者全身状况,肿瘤大小和肝脏功能情况做宏观评估。由于放射性肝损伤潜在风险较大,因此在实施大肝癌立体定向放射治疗前,功能性肝体积评估就显得尤为重要。为此,借鉴肝脏外科肝脏储备功能共识和肝评估决策树,将必需功能性肝体积和剩余功能性肝体积的概念应用于γ-SABR临床实践,有着重要的现实意义。

基于容积旋转弧形调强放疗技术的肝癌立体定向放疗方案评估与位置误差分析

目的 基于容积旋转弧形调强放疗（VMAT）技术，对肝癌立体定向放疗（SABR）方案进行评估，并结合图像引导技术及呼吸管理技术，分析执行中患者位置误差。方法 回顾性分析接受基于VMAT技术的SABR治疗并配合自主深呼气末屏气技术（vDEBH）进行呼吸管理的15例肝癌患者。VMAT计划采用2个部分弧，对治疗方案评估剂量参数，比较VMAT与调强放疗技术（IMRT）的计划质量差异。所有优化方案均经质量保证（QA）验证，包括点剂量和面剂量验证、机器跳数（MU）和出束时间记录。每次治疗时，锥形束CT（CBCT）影像采集2次，包括治疗前1次评估两次治疗间误差和治疗结束后1次评估当次治疗内位移。结果 VMAT和IMRT优化方案的各剂量学参数均满足临床治疗要求，差异无统计学意义（P〉0.05）；相比IMRT，VMAT方案的平均MU降低了28.1%（t=3.064，P〈0.05），且治疗时间缩短了31.6%（t=2.278，P〈0.05）。CBCT图像引导结果显示，采用vDEBH技术可有效减少当次治疗内的位置误差，各方向上的偏移均控制在可容许范围内（〈3 mm）。结论 基于VMAT技术的肝癌SABR治疗计划在靶区体积剂量分布和正常组织受量等剂量学表现与IMRT技术相当，可行性良好且在治疗效率方面优势明显。

放射外科在MD安德森肿瘤中心的实践及进展

非小细胞肺癌（NSCLC）是我国最常见的恶性肿瘤之一.立体放射外科（SABR）,也称立体定向放疗（SBRT）,是一种无创性治疗,在现代精确的影像引导技术下给予局部肿瘤以高剂量、低分割的放射治疗,可获得超过90％的肿瘤局部控制率,已成为不可切除早期NSCLC的标准治疗,也是可手术早期NSCLC的治疗选择之一.美国德州大学MD安德森肿瘤中心（MDACC）作为全美肿瘤治疗排名第一的机构,对NSCLC的放射治疗进行了一系列颇具影响力的SABR临床试验和研究,促进了SABR在早期和晚期NSCLC中的应用.本文将MDACC对SABR的临床应用、研究结果和进展做一总结.

容积调强弧形治疗与质子调强放疗在室性心动过速放射消融中的计划对比研究

目的模拟室性心动过速(VT)患者行立体定向消融体部放疗,探索质子调强放疗(IMPT)的剂量学优势。方法对资料完整的5例患者的胸部定位CT图像均分别勾画左心室的心尖部、心前壁、间隔壁、下壁、外侧壁心肌全层共25个大体靶体积(GTV)。GTV三维外扩5 mm为ITV,ITV外扩3 mm为PTV。每个靶区均分别设计容积调强弧形治疗(VMAT)与IMPT计划。处方剂量为单次25 Gy(RBE)。比较两种计划靶区及危及器官剂量参数。结果中位ITV体积45.40 cm^3(26.72~67.59 cm^3),所有计划均达到足够的靶区覆盖(ITV V95%Rx≥99%)。相比VMAT计划,IMPT组全心、心包及靶区外心脏组织Dmean分别降低44.52%、44.91%、60.16%,左前降支D0.03 cm^3降低17.58%(P<0.05)。按病灶部位分析后发现,IMPT仍可降低绝大多数危及器官剂量,但当病灶位于前壁及心尖时左前降支D0.03 cm^3两者相近,病灶位于前壁或下壁时左回旋支D0.03 cm^3也相近(P>0.05)。结论模拟VT患者立体定向消融体部放疗时,VMAT与IMPT计划均满足临床剂量学要求;而IMPT可降低正常心脏组织受量,具有降低缺血性心脏病、心包炎或心包积液等并发症的潜在获益。