Efficacy and safety of linear accelerator-based fractionated stereotactic radiotherapy for small volume brain metastases / 国际肿瘤学杂志

Objective:To investigate the efficacy and safety of fractionated stereotactic radiotherapy (FSRT) based on linear accelerator for small volume brain metastases.Methods:A total of 21 patients with small volume brain metastases who received FSRT from August 2020 to June 2022 were enrolled as subjects, including 45 lesions. Small-volume brain metastases were defined as ≤3 cm in diameter and ≤6 cm 3 in volume, and the dose/fractionation scheme was 27-30 Gy/3 F or 30-40 Gy/5 F. Three months after radiotherpy, the efficacy of FSRT in small brain metastases and the incidence of radiation brain injury were evaluated, and the incidence of radiation brain injury in subgroup analysis was performed according to the diameter, volume, dose/fractionation scheme, biological effective dose (BED) 10, and location of lesions. Results:Twenty-four lesions (53.33%, 24/45) were evaluated as complete response, another 13 lesions (28.89%, 13/45) were evaluated as partial response, and in the remaining 8 lesions (17.78%, 8/45) were evaluated as stable disease. The local control rate was 100% (45/45), the objective remission rate was 82.22% (37/45), and the intracranial distant progression rate was 23.81% (5/21). During the treatment and follow-up, there were 7 lesions (15.56%, 7/45) of radiation-induced brain injury, and the incidence of symptomatic radiation-induced brain injury was 11.11% (5/45). Subgroup analysis showed that the incidence of radiation brain injury in the group with a lesion diameter of 2-3 cm was higher than that with a lesion diameter of <2 cm group, with a statistically significant difference [80.00% (4/5) vs. 7.50% (3/40), χ2=12.69, P<0.001]; the incidence rate of radiation brain injury in the group with lesion volume of 4-6 cm 3 was higher than that with lesion volume of <4 cm 3 group, with a statistically significant difference [57.14% (4/7) vs. 7.89% (3/38), χ2=7.49, P=0.006]. There was no significant difference in the incidence of radiation brain injury between the dose/fractionation scheme of lesions 27-30 Gy/3 F and 30-40 Gy/5 F [9.52% (2/21) vs. 20.83% (5/24), χ2=0.40, P=0.527]. There was no significant difference in the incidence of radiation brain injury between the BED 10<60 Gy and ≥60 Gy [28.57% (2/7) vs. 13.16% (5/38), χ2=0.22, P=0.641]. There was no significant difference in the incidence of radiation brain injury between the lesions in the same lobe and the single or multiple lesions in different lobes [28.57% (4/14) vs. 9.68% (3/31), χ2=1.38, P=0.240) . Conclusion:FSRT based on linear accelerator is effective for small volume brain metastases. Brain metastases with the diameter <2 cm or volume <4 cm 3 are associated with a lower incidence of radiation brain injury than that of lesions with the diameter of 2-3 cm or volume of 4-6 cm 3.

Single-fraction SRS and multi-fraction SRT for brain metastases from colorectal cancer / 中华放射肿瘤学杂志

Objective:To compare the efficacy and side effects of multi-fraction stereotactic radiotherapy (SRT) and single-fraction stereotactic radiosurgery (SRS) in the treatment of brain metastases from colorectal cancer.Methods:A total of 98 patients with brain metastases from colorectal cancer searched from the database of Professional Committee of Brain Metastasis of Shanghai Anticancer Association were recruited in this study. Among them, 46 patients weretreated with SRT and 52 patients with SRS. Clinical characteristics of all patients were analyzed between two groups and the local tumor control rate, median survival time and the incidence of radiation-induced brain injury were compared between two groups.Results:The objective remission rates (ORR) in the SRT and SRS groups were 76.1% and 67.3%, respectively. The 12-month local tumor control rates were 88.3% and 83.9% between two groups, with no statistical difference ( P=0.689). The median overall survival time of all patients was 11.6 months, 10.8 months in the SRT group and 12.7 months in the SRS group. There was no statistical difference between two groups ( P=0.129). Multivariate analysis showed that the main factors leading to poor prognosis included the number of tumors of >3( P=0.026), low GPA score ( P=0.035), and lack of systematic treatment mode and bevacizumab ( P=0.001). There was no statistical difference in the incidence of acute and late radiation-induced brain injury between two groups. Conclusions:Both SRT and SRS are effective therapies for brain metastases from colorectal cancer. The synergistic application of systematic treatment mode may be one of the main reasons affecting the survival time of the patients.

Research progress on immune checkpoint inhibitors combined with stereotactic ablative body radiotherapy for advanced non-small cell lung cancer / 中华放射肿瘤学杂志

The effect of radiotherapy on anti-tumor immunity is bidirectional, immunotherapy, especially the combination of immune checkpoint inhibitors (ICIs) and radiotherapy, can produce synergistic effects on anti-tumor immunity. Compared with conventional radiotherapy, stereotactic ablative body radiotherapy (SABR) can achieve high-precision and high-dose irradiation on target lesions, and has stronger anti-tumor immune activation effect. At the same time, due to the steep dose gradient, SABR can better protect the surrounding normal tissues, which is an effective means for the rapid control of local lesions in advanced non-small cell lung cancer (NSCLC). ICIs are an important component of standard treatment for advanced NSCLC. There is growing evidence that SABR in combination with ICIs can benefit patients with advanced NSCLC. This article reviews the biological basis and clinical research progress on the combination of these two therapies, aiming to provide reference for the domestic counterparts to better use this new treatment model.

Application of optical surface monitoring system in intra-fraction motion monitoring in frameless cranial stereotactic radiotherapy / 中华放射医学与防护杂志

Objective:To establish a novel clinical application process of the optical surface monitoring system (OSMS) in the cranial frameless stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT), and to assess the accuracy and effectiveness of the OSMS in the intra-fraction motion monitoring of both cranial phantoms and cranial SRT patients fixed using the Q-Fix encompass immobilization system.Methods:The deviations of OSMS in the real-time motion monitoring were assessed by determining the deviations between the displacement of the cranial SRS phantoms detected by the OSMS and the predefined displacement of the Varian Edge six degrees of freedom (6DoF) couch. The ability of the OSMS to conduct real-time monitoring of the head movement was also analyzed when one camera was blocked by the rotary gantry of the accelerator and when the couch was at non-zero angles. Moreover, ten patients who received 50 fractions of cranial frameless SRT were enrolled in this study. All the patients were fixed using the Q-Fix Encompass system, and their intra-fraction motion was monitored using the OSMS. The intra-fraction errors of OSMS real-time monitoring throughout the treatment were obtained from the OSMS logs. The patients received cone-beam computed tomography (CBCT) after the beam delivery, and the six-dimensional errors were obtained as intra-fraction motion errors of the CBCT.Results:For the cranial phantoms, there was a close correlation between the OSMS monitoring deviations and the predefined displacement in six dimensions. The OSMS-detected 3D vector deviations in the translational and rotational directions were (0.28±0.10) mm and (0.15±0.09)°, respectively when the angel both the gantry and couch was 0° and were (0.35±0.13) mm and(0.17±0.09)°, respectively, when one camera was blocked. The OSMS monitoring deviations with the couch at a non-zero degree were greater than those at zero degree. The maximum deviations occurred when the couch was at 270° and were (0.69±0.19) mm and (0.32±0.12)°, respectively, in the translational and rotational directions. For the cranial SRT patients fixed using the Q-Fix Encompass system, the OSMS and CBCT showed comparable intra-fractional motion deviations, which were (0.40±0.26) and (0.29±0.10) mm, respectively in the translational direction and were (0.33±0.20)°and (0.26±0.08)° in the rotational direction.Conclusions:The OSMS is an effective tool for optically guided radiotherapy, which allows for intra-fraction real-time motion monitoring with sub-millimeter accuracy. Therefore, to ensure the accurate preformation of cranial SRS/SRT, it is necessary to conduct the intra-fractional position monitoring using OSMS.

Study on the effects of the changes in respiratory status on gated stereotactic radiotherapy using an in-house developed motion phantom / 中华放射医学与防护杂志

Objective:To evaluate the effects of the changes in respiratory status on gated stereotactic radiotherapy under free breathing guided by real-time position management (RPM).Methods:This study simulated the baseline shift, change in respiratory rate, end-expiratory delay, end-inspiratory delay, and irregular breathing using an in-house developed motion phantom. Moreover, this study analyzed the correlation between the changes in the above states of three plans, three-dimensional conformal radiotherapy(3D-CRT), intensity modulated radiotherapy(IMRT), and volumetric modulated arc therapy(VMAT) and the position of the ball at the center of the motion phantom (L) and the exposed dose of the phantom in the ionization chamber (the dose).Results:The in-house developed phantom presented high setup repeatability and measurement stability. There was a positive correlation between L and the baseline shift ( r = 0.99, P < 0.01). The change in the dose was less than 4% when the baseline shift was less than the setup error, while the dose declined rapidly and was negatively correlated with the baseline shift otherwise ( r= -0.95, P < 0.01). Moreover, there was statistically significant difference in dose when the baseline shift exceeded the setup error or not ( Z = -3.06, P < 0.01). There was no significant difference in the rate of the dose affected by baseline shift in the three plans ( P > 0.05). The changes in respiratory rate had little effect on L and the dose. Both end-inspiratory delay and end-expiratory delay reduced the planned dose of the three plans, with a maximum decrease of up to -1.74%. Furthermore, the end-inspiratory delay has greater effects on the planned dose than the end-expiratory delay( Z = -2.67, P< 0.01). However, there was no significant correlation between the dose and the delay duration ( P > 0.05), and no significant difference in the rate of the planned dose of the three plans affected by respiratory waveform change ( P > 0.05). Irregular breathing had greater effects on the dose. Specifically, the dose from six repeated measurements of 3D-CR, IMRT, VMAT was (709.68±180.00), (751.40±127.16), and (750.00±185.60) cGy, respectively, all less than the prescribed dose with a poor consistency. Conclusions:The changes in the patients′ respiratory status will reduce the dose, especially when the baseline shift exceeds the setup error threshold or large respiratory waveform variation corresponding to irregular breathing occurs. Moreover, there is no correlation between the decrease in the dose and the radiotherapy technology.

Effects of flattening filter on dosimetry in fractionated stereotactic radiotherapy for brain metastases / 中国辐射卫生

@#<b>Objective</b> To investigate the dosimetric differences between volumetric modulated arc therapy (VMAT) with a flattening filter (FF) and flattening filter-free (FFF) VMAT in fractionated stereotactic radiotherapy for brain metastases. <b>Methods</b> Seventeen patients with brain metastases were divided into FF-VMAT group (VMAT plans with the FF mode) and FFF-VMAT group (VMAT plans with the FFF mode). The two groups were compared in terms of target volume dose parameters (<i>D</i>_98%, <i>D</i>_2% and <i>D</i>_mean), the conformal index (<i>CI</i>), the gradient index (<i>GI</i>), the gradient, normal brain tissue dose parameters (<i>V</i>_5Gy, <i>V</i>_10Gy, <i>V</i>_12Gy and <i>D</i>_mean), monitor units, and beam-on time. <b>Results</b> Compared with the FF-VMAT group, the FFF-VMAT group had significantly lower <i>GI</i> (3.33 ± 0.37 <i>vs</i> 3.27 ± 0.35, <i>P</i> = 0.001), a significantly lower gradient [(0.85 ± 0.20) cm <i>vs</i> (0.84 ± 0.19) cm, <i>P</i> = 0.002], a significantly shorter beam-on time [(177.05 ± 62.68) s <i>vs</i> (142.71 ± 34.59) s, <i>P</i> = 0.001], and significantly higher <i>D</i>_2% [(65.69 ± 2.15) Gy <i>vs</i> (66.99 ± 2.03) Gy, <i>P</i> = 0.001] and <i>D</i>_mean [(58.77 ± 1.60) Gy <i>vs</i> (59.95 ± 1.43) Gy, <i>P</i> <0.001]. There were no significant differences in the <i>CI</i>, the<i> D</i>_98%of the target volume, the <i>V</i>_5Gy, <i>V</i>_10Gy, <i>V</i>_12Gy and <i>D</i>_mean of the normal brain tissue, and monitor units between FFF-VMAT and FF-VMAT. <b>Conclusion</b> FFF-VMAT can better protect the normal tissue around the target volume, reduce the beam-on time, and improve treatment efficiency.

Discussion on the indications and timing of targeted therapy and immunotherapy before and after liver transplantation for hepatocellular carcinoma / 器官移植

Liver transplantation is one of the main treatments of early hepatocellular carcinoma (HCC). The recurrence of HCC after liver transplantation severely affects the long-term survival rate of the recipients. Targeted therapy and immunotherapy play a critical role in HCC downstaging, preventing disease progression, reducing recurrence rate, prolonging the survival and improving the quality of life. However, no consensus has been reached on the application of targeted therapy and immunotherapy in recipients undergoing liver transplantation for HCC, including indications, timing and dosage. In this article, clinical research progresses on the indications and timing of targeted therapy and immunotherapy before and after liver transplantation for HCC were reviewed, aiming to provide reference for prolonging the survival of recipients after liver transplantation for HCC.

Clinical efficacy and adverse reactions of SBRT combined with mFOLFOXIRI and cetuximab in liver metastases after colorectal cancer surgery / 国际肿瘤学杂志

Objective:To investigate the efficacy of stereotactic body radiotherapy (SBRT) combined with modified FOLFOXIRI (mFOLFOXIRI, irinotecan, oxaliplatin, leucovorin and fluorouracil) and cetuximab in the treatment of postoperative liver metastases in patients with KRAS, BRAF and NRAS gene wild-type colorectal cancer, and to evaluate treatment-related adverse reactions.Methods:A total of 86 patients with postoperative liver metastases from colorectal cancer diagnosed in Shandong Daizhuang Hospital from January 2018 to January 2021 were selected, all of whom were KRAS, BRAF and NRAS gene wild-type. All patients were divided into control group and study group according to the random number table method, with 43 cases in each group. The patients in the control group were treated with mFOLFOXIRI and cetuximab, 14 days a cycle, for a total of 12 cycles. The patients in the study group were treated with SBRT for liver metastases on the basis of the control group. Two patients in the control group were withdrawn from the study due to intolerance of myelosuppression (grade 4), and patients in the study group were withdrawn from the study due to intolerance of 1 case of myelosuppression, 1 case of gastrointestinal reaction and 1 case of abnormal liver function (all grade 4). The efficacy, median progression-free survival (PFS), median overall survival (OS) and adverse reactions were compared between the two groups after treatment.Results:After 12 cycles of treatment, the objective response rate (ORR) and disease control rate (DCR) of the study group were 55.00% (22/40) and 80.00% (32/40) respectively, which were higher than 31.71% (13/41) and 58.54% (24/41) of the control group, with statistically significant differences ( χ2=4.48, P=0.034; χ2=4.37, P=0.037). After treatment, 14 patients (35.00%) in the study group were resectable, which was higher than 6 patients (14.63%) in the control group, with a statistically significant difference ( χ2=4.52, P=0.034). The median PFS and median OS of the study group were 9.2 months and 19.5 months respectively, which were longer than 6.5 months and 15.2 months of the control group, with statistically significant differences ( χ2=8.83, P=0.015; χ2=7.52, P=0.027). There were no significant differences in incidences of leukopenia [55.00% (22/40) vs. 46.34% (19/41), χ2=0.61, P=0.436], anemia [45.00% (18/40) vs. 39.02% (16/41), χ2=0.30, P=0.585], thrombocytopenia [37.50% (15/40) vs. 31.71% (13/41), χ2=0.30, P=0.584], nausea and vomiting [55.00% (22/40) vs. 48.78% (20/41), χ2=0.31, P=0.575], constipation and diarrhea [20.00% (8/40) vs. 17.07% (7/41), χ2=0.12, P=0.734], liver function damage [35.00% (14/40) vs. 29.27% (12/41), χ2=0.31, P=0.581], peripheral sensory neuropathy [30.00% (12/40) vs. 26.83% (11/41) ), χ2=0.10, P=0.752], acute cholinergic syndrome [12.50% (5/40) vs. 14.63% (6/41), χ2=0.08, P=0.779] and fatigue [52.50% (21/40) vs. 43.90% (18/41), χ2=0.60, P=0.439]. Conclusion:SBRT combined with mFOLFOXIRI and cetuximab is more effective than drug therapy alone in patients with liver metastases after colorectal cancer surgery, which can effectively prolong the survival period, and the adverse reactions are tolerable.

A comparative analysis of SRT and SRS in the treatment of brain metastases from lung adenocarcinoma / 中华放射肿瘤学杂志

Objective@#To compare the clinical efficacy of stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) in the treatment of brain metastases from January 2006 to December 2016, lung adenocarcinoma and analyze the related factors.@*Methods@#In this multi-center retrospective analysis, clinical data of 208 patients with brain metastases from lung adenocarcinoma were retrospectively analyzed and assigned into the SRT (n=86) and SRS groups (n=122). The clinical characteristics of patients in two groups were analyzed. The local tumor control rate, median survival time and radiation brain injury were statistically compared between two groups.@*Results@#At the end of follow-up, the objective response rates (ORR) were 70.9% and 71.3% in the SRT and SRS groups (P=0.772). The local tumor control rates at 12 months were 89% and 86% in the SRT and SRS groups (P=0.383). The median overall survival time of all patients was 14.3 months, 15.6 months in the SRT group and 13.7 months in the SRS group (P=0.349). Multivariate analysis showed that large target volume (P<0.001), low GPA score (P=0.012) and no insensitive gene mutation (P<0.001) were the main factors of poor prognosis. The incidence of late radiation brain injury was 5.8% and 14.8% in two groups (P=0.043).@*Conclusions@#SRT and SRS yield similar clinical efficacy in the treatment of brain metastases from lung adenocarcinoma. SRT may have a lower incidence of late radiation brain injury than SRS.

A comparative analysis of SRT and SRS in the treatment of brain metastases from lung adenocarcinoma / 中华放射肿瘤学杂志

Objective To compare the clinical efficacy of stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) in the treatment of brain metastases from January 2006 to December 2016,lung adenocarcinoma and analyze the related factors.Methods In this multi-center retrospective analysis,clinical data of 208 patients with brain metastases from lung adenocarcinoma were retrospectively analyzed and assigned into the SRT (n=86) and SRS groups (n=122).The clinical characteristics of patients in two groups were analyzed.The local tumor control rate,median survival time and radiation brain injury were statistically compared between two groups.Results At the end of follow-up,the objective response rates (ORR) were 70.9％ and 71.3％ in the SRT and SRS groups (P=0.772).The local tumor control rates at 12 months were 89％ and 86％ in the SRT and SRS groups (P=0.383).The median overall survival time of all patients was 14.3 months,15.6 months in the SRT group and 13.7 months in the SRS group (P=0.349).Multivariate analysis showed that large target volume (P＜0.001),low GPA score (P=0.012) and no insensitive gene mutation (P＜ 0.001) were the main factors of poor prognosis.The incidence of late radiation brain injury was 5.8％ and 14.8％ in two groups (P=0.043).Conclusions SRT and SRS yield similar clinical efficacy in the treatment of brain metastases from lung adenocarcinoma.SRT may have a lower incidence of late radiation brain injury than SRS.

Research progress on stereotactic radiotherapy combined with immunotherapy for malignancies / 中华放射肿瘤学杂志

Surgery,radiotherapy and chemotherapy are three traditional treatments for malignant tumors.With the development of medicine,immunotherapy has been gradually adopted as an emerging therapy of malignancies.Recent clinical studies have demonstrated that the combination of radiotherapy and immunotherapy can induce the abscopal effect and improve the prognosis of patients.Compared with the conventional radiotherapy,stereotactic radiotherapy has a larger single dose and higher accuracy,which is more likely to induce the bystander effect and anti-tumor response.The combination of stereotactic radiotherapy and immunotherapy has been proven to be a more promising therapy in certain clinical trials.However,not all types of tumors can benefit from such combined therapy in clinical practice.The optimal dose,fraction pattern and lesion of radiotherapy,immune enhancement and safety remain to be further clarified.In this article,the research progress,related controversies and future research direction of stereotactic radiotherapy combined with immunotherapy for malignancies were reviewed.

Observation of short-term clinical efficacy and adverse reactions with stereotactic radiotherapy in locally recurrent non-small cell lung cancer / 中华放射肿瘤学杂志

Objective To investigate the short-term clinical efficacy and adverse reactions of stereotactic radiotherapy (SRT) in the treatment of locally recurrent non-small cell lung cancer (NSCLC).Methods Clinical data of 120 cases of recurrent NSCLC after radiotherapy admitted to our hospital from October 2009 to October 2015 were retrospectively analyzed.SRT was adopted for further radiotherapy.The prescription dose was 50％ dose curve surrounding the target area.The total dose was 40-50 Gy,with a single dose of 4-5 Gy for 8-12 times.The chest CT was re-examined every 2 months after radiotherapy.The short-term clinical efficacy and adverse reactions were evaluated.The changes of Karnofsky performance score (KPS) and quality of life (QOL) were recorded before and after radiotherapy.Results One patient terminated the radiotherapy due to grade 3 acute radiation-induced pneumonia,25 patients (21.0％) obtained complete remission (CR),61 cases (51.3％) of partial remission (PR),19 cases (16.0％) of stable disease (SD),14 cases (11.8％) of progress disease (PD),86 cases (72.3％) of objective remission rate (CR+PR),and 105 cases (88.2％) of disease control (CR+PR+SD),respectively.Thirty-one patients experienced radiation-induced pneumonia,23 cases of radiation-induced myelosuppression and 1 case of acute radiation-induced heart injury.All these adverse reactions were mitigated after symptomatic treatment.The KPS was significantly increased from 68.16±15.22 before SRT to 78.39± 11.50 after SRT (P＜0.05).The QOL was considerably elevated from 27.58±5.37 prior to SRT to 38.16±8.39 following SRT (P＜0.01).Conclusion SRT is an efficacious and safe treatment of locally recurrent NSCLC,which yields controllable and tolerable adverse reactions and enhances the QOL of patients.

Analysis of the inter-and intra-fraction setup errors and residual errors during stereotactic radiotherapy for brain metastasis / 中华放射肿瘤学杂志

Objective To evaluate the necessity of arc by arc setup verification in patients with brain metastases receiving stereotactic radiotherapy (SRT) by analyzing the inter-and intra-fraction setup errors and residual errors collected from the ExacTrac X-ray portal image.Methods Clinical data of brain metastases patients treated with SRT in the previous two years were retrospectively analyzed.The ExacTrac X-ray setup images were collected after the normal setup procedure.Setup errors were calculated by registering the cranial bony structures of the ExacTrac X-ray setup images to that of the digitally reconstructed setup images.The inter-and intra-fraction setup errors and residual errors were statistically analyzed.Results Seventy-five patients from 116 lesions received 337 cycles of SRT of the head.The inter-and intra-fraction translational setup errors in the x,y and z directions were (0.93±0.86) mm and (0.15±0.59) mm;(1.83± 1.27) mm and (0.25±0.73) mm;(0.96±0.80) mm and (0.14±0.56) mm,respectively.The inter-and intra-fraction rotational setup errors in the x,y,z directions were (0.65°± 0.62°) and (0.19°± 0.40°);(0.97°±0.94°) and (0.13°± 0.25°);(0.92°± 0.71°) and (0.10°± 0.29°),respectively.The residual translational setup errors in the x,y,z directions were (0.06±0.23) mm,(0.08±0.24) mm and (0.08±0.22)mm,and (0.12°± 0.27°),(0.09°± 0.18°) and (0.06°± 0.19°) for the residual rotational setup errors,respectively.For a reference setup error threshold of 0.7 mm/0.7°,99.1％ of the SRT exceeded the threshold and required setup correction.For 1 006 non-coplanar arcs,rotating the treatment couch from 0° to the treatment angle made 66.4％ of arcs exceed the threshold and require at least once setup correction.Conclusions During SRT for brain metastasis,the inter-and intra-fraction setup errors should be emphasized.It is necessary to perform arc by arc setup error verification.

Performance Evaluation of a CyberKnife VSITM System / 中华放射肿瘤学杂志

Objective To evaluate the accuracy and reliability of the CyberKnife VSI system for stereotactic radiotherapy.Methods First,the mechanical accuracy of the robotic manipulator system,the repeatability of the Iris variable aperture collimator system,the couch position accuracy of the patient positioning system,the tacking precision of the target locating system and the dosimetric beam characteristics of the linac system for each subsystem of CyberKnife VSI system were tested.Finally,the total beam delivery precision of the CyberKnife VSI system was evaluated.Results The mean positioning deviations of the mechanical arm movement of the robotic manipulator system were less than 0.1 mm,and the maximum positioning deviation of single note was ≤ 0.29 mm.The repeatability of the aperture sizes for the Iris variable aperture collimator system was ≤ 0.28 mm.The couch position accuracy of the patient positioning system was＜0.2 mm and the tracking precision of the target locating system was less than 0.5°.The linac beam-laser beam axes coincidence between the Iris and fixed collimators was better than 0.4 mm.The 6-MV beam parameters,such as beam quality and profile,were found within the acceptance limits.The deviations of output reproducibility,linearity and constancy versus linac orientation were less than 1.0％.The transmission factors of two types of collimators were lower than 0.4％.End-to-end test demonstrated that the maximum deviation of the total delivery precision of CyberKnife VSI system was 0.87 mm.Conclusion The CyberKnife VSI system is accurate and reliable for stereotactic radiotherapy.

Case-control study of fractionated stereotactic radiotherapy combined with temozolomide for large brain metastases / 中华放射肿瘤学杂志

Objective To retrospectively analyze and compare the clinical efficacy and safety between fractionated stereotactic radiotherapy (FSRT) combined with and without temozolomide in the treatment of large brain metastases.Methods Between 2009 and 2017,84 patients with large brain metastases (tumor size ≥ 6 cm3) were recruited and assigned into the CRT group (concurrent TMZ and FSRT,n=42) and RT group (FSRT alone,n=42).The radiation dose was 52.0 Gy in 13 fractions or 52.5 Gy in 15 fractions.Patients were reexamined by magnetic resonance imaging (MRI) during treatment.The radiation field would be shrunk if the gross target volume (GTV) was reduced.The clinical efficacy was evaluated at postoperative 2 to 3 months.The primary end-point event was local recurrence-free survival (LRFS) and the secondary end-point events included intracranial progression-free survival (IPFS),progression-free survival (PFS),overall survival (OS),brain metastasis-specific survival (BMSS) and adverse events.The survival rates were assessed with Kaplan-Meier method and log-rank test and monovariate analysis.Results The median GTV in the CRT and RT groups was 16.9 cm3 and 15.7 cm3.During the treatment,75％ of the lesions in the CRT group were reduced compared with 34％ in the RT group (P=0.000).The local control (LC) rate in the CRT and RT groups was 100％ and 98％.The median follow-up time was 16.1 months (range,2.1-105.7 months).In the CRT group,the LRFS (P=0.040),IPFS (P=0.022),PFS (P=0.045),OS (P=0.013) and BMSS (P=0.006) were significantly better than those in the RT group,respectively.In the CRT group,the incidence of grade Ⅰ-Ⅱ gastrointestinal adverse events was 33％,significantly higher compared with 26％ in the RT group (P=0.006).No grade Ⅳ-Ⅴ adverse events occurred in both groups.Conclusion Combined application of temozolomide and FSRT can further enhance the LC and survival rates and do not increase the risk of severe adverse events in patients diagnosed with large brain metastases.

Utilization rate of gold fiducial markers and reasons for abandonment in CyberKnife stereotactic body radiation therapy / 中华放射肿瘤学杂志

Objective To investigate the utilization rate of gold fiducial markers and reasons for abandonment of gold fiducial markers in the CyberKnife VSI System, and to provide reference data for implantation of gold fiducial markers and radiotherapy planning. Methods From March to August,2017,a total of 47 patients had gold fiducial markers implanted or pasted. In those patients, 42 patients had gold fiducial markers implanted,including 32 receiving computed tomography(CT)-guided 3D-printing coplanar template assisted implantation, 1 receiving CT-guided 3D-printing non-coplanar template assisted implantation,1 receiving CT-guided implantation,and 8 receiving ultrasound-guided implantation. A total of 44 patients received the CyberKnife treatment, including 2 patients who failed to use gold fiducial markers and were treated with spine tracking instead and 3 patients missing the treatment for other reasons. The numbers of utilized and abandoned gold fiducial markers were recorded for calculation of the utilization and abandonment rates. The reasons for abandonment of gold fiducial markers were analyzed and classified. Results A total of 134 gold fiducial markers were implanted into or pasted to the 44 patients.In all the gold fiducial markers, 111 were utilized and 23 abandoned, yielding a utilization rate of 82.8% and an abandonment rate of 17.2%.The reasons for abandonment of gold fiducial markers included large rigidity error(26.1%), unqualified implanted fold fiducial markers(17.4%), displacement of gold fiducial markers(26.1%), and others(30.4%). Conclusions Compared with the CT-guided or ultrasound-guided implantation of gold fiducial markers, the CT-guided 3D-printing coplanar or non-coplanar template assisted implantation of gold fiducial markers requires only two puncture needles for each implantation and implants two gold fiducial markers by a single needle,which reduces the number of puncture needles,risk of puncture-induced injury,and incidence of complications after implantation. Not all the gold fiducial markers implanted by a variety of ways will be utilized. Some gold fiducial markers will be abandoned for different reasons,which should be taken into account during implantation of gold fiducial markers.

Clinical efficacy of CyberKnife stereotactic body radiation therapy for hepatic hilar cancer / 中华放射肿瘤学杂志

Objective To evaluate the efficacy and safety of CyberKnife stereotactic body radiation therapy (SBRT) in the treatment of hepatic hilar cancer.Methods A retrospective study was performed on the clinical data of 36 patients with hepatic hilar cancer who were admitted to our hospital and treated with CyberKnife SBRT from 2009 to 2015.In the 36 patients,37 lesions were found with tumor diameters ranging from 1.5 to 5.5 mm (median diameter 3 cm).The Synchrony respiratory tracking system was used for 21 lesions in 20 patients,while the XSight spinal tracking system was used for 16 lesions in 16 patients.Local progression was evaluated based on contrast-enhanced computed tomography and/or magnetic resonance imaging.The Kaplan-Meier method was used to calculate local control (LC) and overall survival (OS) rates,and the log-rank test was used for survival comparison and univariate prognostic analysis.Results The median follow-up time was 12.7 months.The 1-and 2-year postoperative LC rates were 90％ and 76％,respectively.The 1-year OS and progression-free survival (PFS) rates were 63％ and 39％,respectively.The median OS and PFS times were 15.2 and 10 months,respectively.The incidence of grade 3 adverse reactions was 11％.Conclusions The CyberKnife SBRT is a safe and effective way to treat hepatic hilar cancer.

Clinical efficacy of stereotactic radiation therapy combined with temozolomide on recurrent brain glioma / 中南大学学报(医学版)

Objective:To investigate the clinical efficacy of stereotactic radiation therapy combined with temozolomide on recurrent glioma.Methods:A total of 36 patients with recurrent glioma were retrospectively analyzed and divided into a control group (n=12),who received stereotactic radiation therapy,and an experimental group (n=24),who received stereotactic radiation therapy plus temozolomide.The clinical efficacy and adverse reactions for the 2 groups were compared.Results:Total effective rate and local control rate for clinical treatment were 66.67％ and 93.94％,respectively.Late adverse reaction was not observed.The effective rate and local control rate in the experimental group were 77.27％ and 95.45％,which were slight higher than those in the control group,with no statistical significance (P＞0.05).The 0.5-,1-,2-,3-year follow-up total survival rates were 90.91％,63.64％,42.42％,and 15.15％,respectively.The 0.5-,1-,2-,3-year follow-up survival rates in the experimental group were 95.45％,72.72％,54.54％ and 22.73％,respectively,while those in the control group were 81.82％,45.45％,18.18％,and 0％,respectively.Survival analysis showed the survival time for the experimental group was significantly longer than that of the control group (30.00 months vs 14.00 months,P=0.010).Conclusion:Stereotactic radiation therapy combined with temozolomide for recurrent glioma is effective,and it has positive effect on improving the clinical efficacy and survival rate for the patients.

Application of cyberknife in treatment of retroperitoneal lymph node metastatic tumors in 81 cases / 中华放射肿瘤学杂志

Objective@#To evaluate the clinical efficacy and side effects of cyberknife therapy in the treatment of retroperitoneal lymph node metastatic tumor.@*Methods@#Among the 81 patients presenting with postoperative retroperitoneal lymph node metastases, 33 cases suffered from abdominal pain or low back pain, 7 had unilateral hydronephrosis and ureteral dilatation, and 8 developed unilateral or bilateral lower limb swelling. Using stereotactic radiotherapy with a cyberknife, DT was delivered at 33-45 Gy/3-6 F. The improvement of symptoms, objective tumor response rate, and irradiation-induced side effects were observed.@*Results@#At 4 weeks after treatment, pain and swelling of the lower extremities were completely mitigated, and hydronephrosis was fully healed in all patients. Enhanced CT or MRI was performed every 2 to 3 months. After 6-month follow-up, the complete response (CR) rate was calculated as 77%(62/81), 21%(17/81) for the partial response (PR) rate, 3%(2/81) for the stable disease (SD) rate and the effective rate (CR+ PR) was 98%.No case progressed. The main side effect was intestinal injury, including grade 1 in 16%(13/81), grade 2 in 9%(7/81). Multivariate analysis demonstrated the CR rate was not correlated with the type of the primary tumor or the size of the tumor (P>0.05), but was significantly associated with the distance of>0.5 cm between the tumor and intestine and the BED (α/β=10)>70 Gy of the tumor irradiation (P<0.01). The incidence of irradiation-related side effects was correlated with the maximum diameter of tumor>5 cm and the distance of<0.5 cm between the tumor and intestine (P<0.01).@*Conclusion@#Cyberknife is an efficacious and safe approach in the treatment of retroperitoneal lymph node metastatic tumors.

Study of oligodendrocyte metastasis in non-small cell lung cancer by stereotactic radiotherapy / 实用肿瘤学杂志

Non-small cell lung cancer(NSCLC)is the most common type of distant metastasis in all types of lung cancer ex-cept for SCLC,including brain,bone,liver and adrenal gland.Of the patients with distant metastases in NSCLC,not all cases are multi-ple and extensive,with nearly 7% of patients presenting with isolated extrapulmonary metastases.This particular form of advanced tumor metastasis is called NSCLC oligometastatic.Treatment of oligometastatic is mainly local treatment,which includes stereotactic radiotherapy(STR),surgical resection and radiofrequency ablation.The aim of this article is to discuss the effect of SRT on the micro-metastasis of common distant metastatic organs in NSCLC.