Treatment for paraganglioma with stereotactic radiotherapy

BACKGROUND Paragangliomas(PG)are rare neoplasms of neuroendocrine origin that tend to be highly vascularized,slow-growing,and usually sporadic.To date,common treatment options are surgical resection(SR),with or without radiation therapy(RT),and a watch-and-wait approach.AIM To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT(FSRT)treatment in unresectable PG(uPG).METHODS We retrospectively evaluated patients with uPG(medically inoperable or refused SR)treated with FSRT with a Cyberknife System(Accuray Incorporated,Sunnyvale,California).Toxicity and initial efficacy were evaluated.RESULTS From May 2009 to January 2023,6 patients with a median age of 68(range 20-84)were treated with FSRT.The median delivered dose was 21 Gy(range 20-30 Gy)at a median isodose line of 75.5%(range 70%-76%)in 4 fractions(range 3-5 fractions).The median volume was 13.6 mL(range 12.4-65.24 mL).The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively.Site of origin involved were the timpa-nojugular glomus(4/6),temporal bone,and cervical spine.In 1 of the 6 patients,the follow-up was insufficient;5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%.We observed negligible toxicities during and after RT.The majority of patients showed stable symptoms during follow-up.Only 1 patient developed spine metastases.CONCLUSION Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

Effect of Stereotactic Body Radiation Therapy on Diverse Organ Lesions in Advanced Non-Small Cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors

Objective The combination of stereotactic body radiation therapy(SBRT)and immune checkpoint inhibitors(ICIs)is actively being explored in advanced non-small-cell lung cancer(NSCLC)patients.However,little is known about the optimal fractionation and radiotherapy target lesions in this scenario.This study investigated the effect of SBRT on diverse organ lesions and radiotherapy dose fractionation regimens on the prognosis of advanced NSCLC patients receiving ICIs.Methods The medical records of advanced NSCLC patients consecutively treated with ICIs and SBRT were retrospectively reviewed at our institution from Dec.2015 to Sep.2021.Patients were grouped according to radiation sites.Progression-free survival(PFS)and overall survival(OS)were recorded using the Kaplan-Meier method and compared between different treatment groups using the log-rank(Mantel-Cox)test.Results A total of 124 advanced NSCLC patients receiving ICIs combined with SBRT were identified in this study.Radiation sites included lung lesions(lung group,n=43),bone metastases(bone group,n=24),and brain metastases(brain group,n=57).Compared with the brain group,the mean PFS(mPFS)in the lung group was significantly prolonged by 13.3 months(8.5 months vs.21.8 months,HR=0.51,95%CI:0.28–0.92,P=0.0195),and that in the bone group prolonged by 9.5 months with a 43%reduction in the risk of disease progression(8.5 months vs.18.0 months,HR=0.57,95%CI:0.29–1.13,P=0.1095).The mPFS in the lung group was prolonged by 3.8 months as compared with that in the bone group.The mean OS(mOS)in the lung and bone groups was longer than that of the brain group,and the risk of death decreased by up to 60%in the lung and bone groups as compared with that of the brain group.When SBRT was concurrently given with ICIs,the mPFS in the lung and brain groups were significantly longer than that of the bone group(29.6 months vs.16.5 months vs.12.1 months).When SBRT with 8–12 Gy per fraction was combined with ICIs,the mPFS in the lung group was significantly prolonged as compared with that of the bone and brain groups(25.4 months vs.15.2 months vs.12.0 months).Among patients receiving SBRT on lung lesions and brain metastases,the mPFS in the concurrent group was longer than that of the SBRT→ICIs group(29.6 months vs.11.4 months,P=0.0003 and 12.1 months vs.8.9 months,P=0.2559).Among patients receiving SBRT with<8 Gy and 8–12 Gy per fraction,the mPFS in the concurrent group was also longer than that of the SBRT→ICIs group(20.1 months vs.5.3 months,P=0.0033 and 24.0 months vs.13.4 months,P=0.1311).The disease control rates of the lung,bone,and brain groups were 90.7%,83.3%,and 70.1%,respectively.Conclusion The study demonstrated that the addition of SBRT on lung lesions versus bone and brain metastases to ICIs improved the prognosis in advanced NSCLC patients.This improvement was related to the sequence of radiotherapy combined with ICIs and the radiotherapy fractionation regimens.Dose fractionation regimens of 8–12 Gy per fraction and lung lesions as radiotherapy targets might be the appropriate choice for advanced NSCLC patients receiving ICIs combined with SBRT.

Comprehensive Treatment Uncertainty Analysis and PTV Margin Estimation for Fiducial Tracking in Robotic Liver Stereotactic Body Radiation Therapy

Objective This study aims to quantify the uncertainties of CyberKnife Synchrony fiducial tracking for liver stereotactic body radiation therapy(SBRT)cases,and evaluate the required planning target volume(PTV)margins.Methods A total of 11 liver tumor patients with a total of 57 fractions,who underwent SBRT with synchronous fiducial tracking,were enrolled for the present study.The correlation/prediction model error,geometric error,and beam targeting error were quantified to determine the patient-level and fraction-level individual composite treatment uncertainties.The composite uncertainties and multiple margin recipes were compared for scenarios with and without rotation correction during treatment.Results The correlation model error-related uncertainty was 4.3±1.8,1.4±0.5 and 1.8±0.7 mm in the superior-inferior(SI),left-right,and anterior-posterior directions,respectively.These were the primary contributors among all uncertainty sources.The geometric error significantly increased for treatments without rotation correction.The fraction-level composite uncertainties had a long tail distribution.Furthermore,the generally used 5-mm isotropic margin covered all uncertainties in the left-right and anterior-posterior directions,and only 75%of uncertainties in the SI direction.In order to cover 90%of uncertainties in the SI direction,an 8-mm margin would be needed.For scenarios without rotation correction,additional safety margins should be added,especially in the superior-inferior and anterior-posterior directions.Conclusion The present study revealed that the correlation model error contributes to most of the uncertainties in the results.Most patients/fractions can be covered by a 5-mm margin.Patients with large treatment uncertainties might need a patient-specific margin.

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.

Radiation pneumonitis after stereotactic radiation therapy for lung cancer

Stereotactic body radiation therapy(SBRT)has a locacontrol rate of 95%at 2 years for non-small cell lungcancer(NSCLC)and should improve the prognosis oinoperable patients,elderly patients,and patients withsignificant comorbidities who have early-stage NSCLCThe safety of SBRT is being confirmed in internationalmulti-institutional PhaseⅡtrials for peripheral lungcancer in both inoperable and operable patients,bureports so far have found that SBRT is a safe and effective treatment for early-stage NSCLC and early metastatic lung cancer.Radiation pneumonitis(RP)is oneof the most common toxicities of SBRT.Although mospost-treatment RP is Grade 1 or 2 and either asymptomatic or manageable,a few cases are severe,symptomatic,and there is a risk for mortality.The reportedrates of symptomatic RP after SBRT range from 9%to28%.Being able to predict the risk of RP after SBRT isextremely useful in treatment planning.A dose-effecrelationship has been demonstrated,but suggesteddose-volume factors like mean lung dose,lung V20and/or lung V2.5 differed among the reports.We foundthat patients who present with an interstitial pneumo-nitis shadow on computed tomography scan and high levels of serum Krebs von den Lungen-6 and surfactant protein D have a high rate of severe radiation pneumo-nitis after SBRT.At our institution,lung cancer patients with these risk factors have not received SBRT since 2006,and our rate of severe RP after SBRT has de-creased significantly since then.

Role of stereotactic body radiation therapy for hepatocellular carcinoma

The integration of new technologies has raised an interest in liver tumor radiotherapy,with literature evolving to support its efficacy.These advances,particularly stereotactic body radiation therapy(SBRT),have been critical in improving local control or potential cure in liver lesions not amenable to first-line surgical resection or radiofrequency ablation.Active investigation of SBRT,particularly for hepatocellular carcinoma(HCC),has recently started,yielding promising local control rates.In addition,data suggest a possibility that SBRT can be an alternative option for HCC unfit for other local therapies.However,information on optimal treatment indications,doses,and methods remains limited.In HCC,significant differences in patient characteristics and treatment availability exist by country.In addition,the prognosis of HCC is greatly influenced by underlying liver dysfunction and treatment itself in addition to tumor stage.Since they are closely linked to treatment approach,it is important to understand these differences in interpreting outcomes from various reports.Further studies are required to validate and maximize the efficacy of SBRT by a large,multi-institutional setting.

Role of stereotactic body radiotherapy for oligometastasis from colorectal cancer

Systemic chemotherapy has enabled prolongation of survival in patients with stage IV colorectal cancer. This has subsequently increased the relative significance of local therapy for patients with oligometastases because they can be cured by removal of oligometastatic lesions. One of the most frequently reported tumor histologies for oligometastases is colorectal cancer. Resection is the standard therapy in most settings of oligometastases. Recently, studies have shown that stereotactic body radiotherapy (SBRT) may become a treatment option that provides high local control with minimal morbidity. Two-year local control rates following SBRT for hepatic and pulmonary oligometastases are almost over 80% and are even higher for patients treated with high-dose regimens. The indications of SBRT for other metastatic sites or conditions include isolated lymph nodes, spinal and adrenal metastasis, and post-surgical pelvic recurrence. Many retrospective studies have indicated that SBRT for various lesions results in good outcomes with low morbidity, both in the curative and palliative setting. However, few reports with a high level of evidence have indicated the efficacy of SBRT compared to standard therapy. Hereafter, the optimal indication of SBRT needs to be prospectively investigated to obtain convincing evidence.

Stereotactic body radiation therapy in patients with hepatocellular carcinoma: A mini-review

Stereotactic body radiation therapy(SBRT) is an emerging treatment for hepatocellular carcinoma. This technique results in excellent local control rates with favorable toxicity profile despite being predominantly used in heavily pretreated patients or those unsuitable for other local therapies. SBRT may be used as a sole treatment or in combination with other local therapies as well as a bridging strategy for patient awaiting liver transplants. This brief review describes current practice of SBRT with respect to radiation technique, patient selection and treatment concepts. It summarizes available evidence from retroand prospective studies evaluating SBRT alone, SBRT in combination with other treatments and SBRT compared to other local treatment approaches.

Advances of stereotactic body radiotherapy in pancreatic cancer

Pancreatic cancer（PCA） is one of the most aggressive tumors with few effective treatment modalities. It is the 4th and 7th leading cause of cancer death in the United States and China, respectively. At the time of diagnosis, only 20% of cases present with a resectable tumor, and about 40% with a locally advanced tumor that is considered unresectable. Even resected patients still have a poor prognosis, with an incidence of local recurrence ranging from 20% to 60%. It is also reported that up to 30% of PCA patients die from locally obstructive disease with few or no distant metastases. These findings have highlighted the importance of local radiation therapy in the treatment of PCA. As the role of conventional chemoradiotherapy remains controversial, the dawn of the pancreas stereotactic body radiation therapy（SBRT） era represents a potential paradigm shift in the management of PCA. SBRT delivers a higher biological effective dose to the tumor with sharp dose escalation in a shorter treatment time course. Pancreas SBRT is a novel therapeutic option to achieve local tumor control with minimal toxicity. Herein, we review the advancement of SBRT for PCA patients with different stages of pancreatic adenocarcinoma.

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.

Partial and Full Arc Volumetric Modulated Arc Therapy in Lung Cancer Stereotactic Body Radiotherapy with Different Definitions of Internal Target Volume Based on 4D CT

Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.

High rate of complete histopathological response in hepatocellular carcinoma patients after combined transarterial chemoembolization and stereotactic body radiation therapy

BACKGROUND Liver transplantation(LT)presents a curative treatment option in patients with early stage hepatocellular carcinoma(HCC)who are not eligible for resection or ablation therapy.Due to a risk of up 30%for waitlist drop-out upon tumor progression,bridging therapies are used to halt tumor growth.Transarterial chemoembolization(TACE)and less commonly stereotactic body radiation therapy(SBRT)or a combination of TACE and SBRT,are used as bridging therapies in LT.However,it remains unclear if one of those treatment options is superior.The analysis of explant livers after transplantation provides the unique opportunity to investigate treatment response by histopathology.AIM To analyze histopathological response to a combination of TACE and SBRT in HCC in comparison to TACE or SBRT alone.METHODS In this multicenter retrospective study,27 patients who received liver transplantation for HCC were analyzed.Patients received either TACE or SBRT alone,or a combination of TACE and SBRT as bridging therapy to liver transplantation.Liver explants of all patients who received at least one TACE and/or SBRT were analyzed for the presence of residual vital tumor tissue by histopathology to assess differences in treatment response to bridging therapies.Statistical analysis was performed using Fisher-Freeman-Halton exact test,Kruskal-Wallis and Mann-Whitney-U tests.RESULTS Fourteen patients received TACE only,four patients SBRT only,and nine patients a combination therapy of TACE and SBRT.There were no significant differences between groups regarding age,sex,etiology of underlying liver disease or number and size of tumor lesions.Strikingly,analysis of liver explants revealed that almost all patients in the TACE and SBRT combination group(8/9,89%)showed no residual vital tumor tissue by histopathology,whereas TACE or SBRT alone resulted in significantly lower rates of complete histopathological response(0/14,0%and 1/4,25%,respectively,P value<0.001).CONCLUSION Our data suggests that a combination of TACE and SBRT increases the rate of complete histopathological response compared to TACE or SBRT alone in bridging to liver transplantation.

Liver magnetic resonance imaging for evaluation of response to treatment after stereotactic body radiation therapy of hepatocellular carcinoma

BACKGROUND Although stereotactic body radiation therapy(SBRT)is increasingly used,its application has not yet been regulated by the main international guidelines,leaving the decision to multidisciplinary teams.AIM To assess magnetic resonance imaging(MRI)features of hepatocellular carcinoma(HCC)treated with SBRT,highlighting the efficacy of the treatment and the main aspects of the lesion before and after the procedure.METHODS As part of a retrospective study,49 patients who underwent SBRT for HCC between January 2013 and November 2019 were recruited.Each patient under went a pre-treatment MRI examination with a hepatospecific contrast agent and a similar followup examination within 6 mo of therapy.In addition,22 patients underwent a second follow-up examination after the first 6 mo.The following characteristics were analysed:Features analysed compared to pre-treatment MRI examination,presence or absence of infield and outfield progression,ring-like enhancement,signal hyperintensity in T2-weighted sequences in the perilesional parenchyma,capsular retraction,and"band"signal hypointensity in T1-weighted gradient echo fat saturated sequences obtained during hepatobiliary excretion.RESULTS Signal hyperintensity in the T2-weighted sequences showed a statistically significant reduction in the number of lesions at the post-SBRT first control(P=0.0006).Signal hyperintensity in diffusionweighted imaging-weighted sequences was decreased at MRI first control(P<0.0001).A statistically significant increase of apparent diffusion coefficient values from a median of 1.01 to 1.38 at the first post-control was found(P<0.0001).Capsular retraction was increased at the late evaluation(P=0.006).Band-like signal hypointensity in the hepatobiliary phase was present in 94%at the late control(P=0.006).The study of the risk of outfield progression vs infield progression revealed a hazard ratio of 9.CONCLUSION The efficacy of SBRT should be evaluated not in the first 6 mo,but at least 9 mo post-SBRT,when infield progression persists at very low rates while the risk of outfield progression increases significantly.

Stereotactic body radiation therapy:A good dance partner of oligometastatic non-small cell lung cancer to the sound of SINDAS study

The European Organization for Research on Treatment of Cancer Research published a consensus statement to establish the key criteria to define oligometastatic disease(OMD).According to those criteria,all lesions(both primary and metastatic)should be amenable to radical intent treatment with acceptable toxicity.Several retrospective studies have shown that adding local ablative therapy to the treatment of OMD improves outcomes;however,due to the diverse selection criteria and treatment strategies used in those studies,it is difficult to compare directly results to draw definitive conclusions.In recent years,prospective phase II trials,such as the SABR-COMET and"Oligomez"trials,have shown that stereotactic body radiation therapy(SBRT)improves outcomes in patients with OMD.More recently,interim results of the randomised phase 3 SINDAS trial were reported at the annual meeting of the American Society of Clinical Oncology 2020 demonstrating that upfront SBRT added to systemic treatment with tyrosine kinase inhibitors yielded a significant benefit in both progression-free survival and overall survival in patients with epidermal growth factor receptor-mutant oligometastatic non-small cell lung cancer.In the present editorial,we review the definition and historical context of advanced non-small cell lung cancer with OMD.In addition,we review the scientific evidence for local ablative therapy and SBRT and discuss the results of recently published prospective studies.We also discuss in depth the results of the SINDAS study,including the strengths and weaknesses of the study and the barriers to extrapolating these results to routine clinical practice.

Stereotactic radiation therapy in the era of precision medicine for cancer

Unlike conventional radiation therapy, stereotactic radiation therapy(SRT) is an emerging tumor-ablative radiation technology with a high-dose delivery to targets while dramatically sparing adjacent normal tissues. The strengths of SRT involve noninvasive and short-course treatment, high rates of tumor local control with a low risk of side effects. Although the scientific concepts of radiobiology fail to be totally understood currently, SRT has shown its potential and advantages against various tumors, especially for those adjacent to less tolerable normal organs(spinal cord, optic nerve, bowels, etc.). Nowadays, the clinical efficacy of SRT has been widely confirmed in certain patients, especially for those medically inoperable, unwilling to undergo surgery, medicine ineffective with tumor progression. Moreover, SRT could be properly used as palliative treatment aiming at relieving local symptoms and pain, and eventually achieving a potential survival benefit of several months. However, the weaknesses of SRT relate to inevitable radiation-induced toxicities as well as the inaccessibility of prophylactic irradiation. In general, one flaw cannot obscure the splendor of the jade. The emergence and development of SRT has opened the new era of precision radiation therapy, and SRT will probably step gloriously onto the remarkable stage for precision medicine.

Target migration from re-inflation of adjacent atelectasis during lung stereotactic body radiotherapy

Stereotactic body radiotherapy(SBRT) is a widely accepted option for the treatment of medically inoperable early-stage non-small cell lung cancer(NSCLC).Herein,we highlight the importance of interfraction image guidance during SBRT.We describe a case of earlystage NSCLC associated with segmental atelectasis that translocated 15 mm anteroinferiorly due to re-expansion of the adjacent segmental atelectasis following the first fraction.The case exemplifies the importance of crosssectional image-guided radiotherapy that shows the intended target,as opposed to aligning based on rigid anatomy alone,especially in cases associated with potentially "volatile" anatomic areas.

Treatment-Plan Comparison of Three Advanced Radiation Treatment Modalities for Fractionated Stereotactic Radiotherapy to the Head and Neck

Purpose: Fractionated stereotactic radiosurgery (FSRS) can be given with at least three modalities: Gamma Knife, with the noninvasive frameless extend system (GKE);linear accelerator-based volumetric modulated arc therapy (VMAT);and intensity-modulated proton therapy (IMPT). We extracted treatment plans for patients who had received FSRS with GKE for recurrent skull base or intracranial tumors, created corresponding plans for VMAT and IMPT, and compared the quality of the three sets of plans. Methods and materials: Plans were extracted for 9 patients with recurrent malignant skull-base tumors (n = 6) or large intracranial tumors (n = 3) who had received FSRS with GKE (median dose 24 Gy in 3 fractions) in 2013 through 2015. Plans for VMAT were generated with a TrueBeam STx LINAC machine using 6-MV photons, and plans for IMPT were generated with multi-field optimization. The optimized VMAT and IMPT plans were normalized to achieve the best possible target coverage while meeting the same dose-volume constraints on organs at risk (OARs) as the GKE plans. Plans were evaluated on the basis of target coverage, conformity index, homogeneity index, gradient index, and treatment efficiency. Results: The median target volume was 10.2 cm3 (range 1.9 - 33.8 cm3). The VMAT and IMPT plans met all OAR constraints, and target coverage and conformity were comparable among all plans. VMAT and IMPT plans showed significantly better target uniformity and treatment delivery efficiency (P P Conclusion: FSRS for skull base and large intracranial lesions delivered by VMAT and IMPT can achieve comparable target coverage, conformity, and sparing of critical structure as the GKE while providing superior target uniformity and treatment delivery efficiency. The GKE had superior high-dose gradients outside the target and thus better protected surrounding normal structures.

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.

Dosimetric Comparison of Different Prescription Modes in Lung Stereotactic Body Radiation Therapy

The purpose of this study was to compare the dose-volume statistics of stereotactic body radiotherapy (SBRT) for lung cancer between planning target volume (PTV): D95 and gross tumor volume (GTV): D99 dose prescriptions using Monte Carlo (MC) calculation. Plans for 183 patients treated between October 2010 and April 2013 were generated based on four-dimensional (4D) computed tomography (CT) under free breathing. A uniform margin of 8 mm was added to the internal target volume (ITV) to generate PTV. A leaf margin of 2 mm was added to the PTV. The plans were calculated with two different dose prescription methods: 40 Gy to cover 95% of the PTV (PTV prescription) and 44 Gy to cover 99% of the GTV (GTV prescription). A 6-MV photon beam was used. A dose-volume histogram (DVH) analysis was performed for dose to the GTV using PTV and GTV dose prescriptions. For each treatment plan, we evaluated the minimum dose to 99% of the GTV (D99). The D99 of GTV was 44.5 ± 1.9 Gy and 44.0 ± 0.0 Gy for PTV and GTV prescriptions, respectively. The dose to the GTV had wide variations with PTV prescription. We recommend that GTV based dose prescription should be used to standardize dose to the tumor and to achieve highly conformal dose distributions in SBRT for lung cancer.

Stereotactic radiosurgery:a“targeted”therapy for cancer

The developments of medicine always follow innovations in science and technology.In the past decade,such innovations have made cancer-related targeted therapies possible.In general,the term "targeted therapy" has been used in reference to cellular and molecular level oriented therapies.However,improvements in the delivery and planning of traditional radiation therapy have also provided cancer patients more options for "targeted" treatment,notably stereotactic radiosurgery(SRS) and stereotactic body radiotherapy(SBRT).In this review,the progress and controversies of SRS and SBRT are discussed to show the role of stereotactic radiation therapy in the ever evolving multidisciplinary care of cancer patients.