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.

Advantages of tracking no less than three gold markers in radiotherapy with CyberKnife / 中华放射肿瘤学杂志

Objective To analyze the differences between CyberKnife radiotherapy with different numbers of gold markers.Methods A total of 424 patients undergoing CyberKnife with gold markers from 2013 to 2014 were enrolled and analyzed.In these patients,330 patients with no less than 3 gold markers were assigned to observation group and 94 patients with less than 3 gold markers were assigned to control group.The setup error and treatment error were recorded and analyzed for each patient.Results The mean setup error and mean treatment error were 0.031 mm and 0.314 mm in the observation group and 0.057 mm and 1.122 mm in the control group,respectively.Conclusion Tracking no less than 3 gold markers can substantially improve the accuracy and quality of treatment.

Impacts of different tracking methods on short-term therapeutic effect of cyberknife in treatment of lung cancer / 中华放射肿瘤学杂志

Objective To investigate the impacts of fiducial tracking and X-sight tracking on the short-term therapeutic effect of cybernikife in the treatment of lung cancer.Methods Retrospective analysis was performed on 64 lung cancer patients (72 lesions),including 40 primary tumor patients (41 lesions) and 24 metastatic tumor patients (31 lesions),who were treated with cyberknife.Fiducial tracking was used for 45 lesions,while X-sight tracking was used for 27 lesions.The planning target volume was covered by 70％-94％ (median 80％) isodose contour.The irradiation dose was 60 Gy/3 fractions.The relationship between short-term therapeutic effect and tracking method was determined.Results Overall,the lesions undergoing fiducial tracking showed significantly higher response rate than those undergoing X-sight tracking (93％ vs.74％,x2 =6.84,P=0.033),and so was in lower lung lesions (15％ vs.7％,x2 ＝7.18,P=0.028).But the two tracking methods achieved similar effects in upper lung lesions (28％ vs.12％,x2 =2.36,P =0.310).In the lesions with treatment volumes smaller than 15 cm3,the fiducial tracking achieved significantly higher response rate than the X-sight tracking (25 ％ vs.12％,x2 =6.53,P =0.038),but the two tracking methods achieved similar effects in the lesions with treatment volumes not smaller than 15 cm3 (17％ vs 8％,x2 =1.57,P =0.460).Overall,the lesions undergoing X-sight tracking had significantly highertreatment failure rate than fiducial tracking (1 9 ％ vs.2 ％,x2 =6.33,P =0.021).Conclusions Different tracking methods may lead to different therapeutic effects of cyberknife in the treatment of lung cancer,which are related to lesion location and treatment volume.

Value of local progression-free survival for evaluating local outcome of peripheral lung cancer treated by cyberknife / 中华放射肿瘤学杂志

Objective To investigate the value of local progression-free survival (LPFS) for evaluating the local long-term outcome of peripheral lung cancer treated by cyberknife.Methods Retrospective analysis was performed on the clinical records of 81 cyberknife-treated lung cancer patients (90 foci),including 43 primary lung cancer patients (43 foci) and 38 metastatic lung cancer patients (47 foci).Of all the patients,58(63 foci) were treated at a dose of 60 Gy/3 fractions (20 Gy/fraction),and 23 (27 foci) at a dose of 54 Gy/3 fractions (18 Gy/fraction).The short-term treatment outcome and LPFS were used as the indices for observation;a logistic regression was used for analyzing the predictive value of LPFS for local long-term treatment outcome.Results After the evaluation of short-term treatment outcome,63％ of all the foci needed further evaluation.As the follow-up lasted,the number of foci which needed further evaluation decreased,most rapidly during 0.5-2 years after treatment.Re-evaluation results had predictive value for the treatment outcome in the subsequent follow-up,but the predictive value declined as the follow-up lasted.Conclusions LPFS is a recommendable index for evaluating the local outcome of primary or metastatic lung cancer treated by cyberknife,and it also has predicative value for local long-term treatment outcome.

Clinical observation on the therapeutic efficacy of cyberknife for primary or metastastic retroperitoneal tumors / 中华放射肿瘤学杂志

ObjectiveTo evaluate the early response rate and radiation toxicity of cyberknife in the treatment of primary or metastasticretroperitoneal tumors.MethodsTwenty-eightpatientswith retroperitoneal tumors were treated with cyberknife.The total doses were 2000-6000 cGy ( median 4500 cGy) and biological effective doses were 3750-10080 cGy (median 7680 cGy) in 2-10 fractions (median 5).Of all patients,3 received three dimensional conformal radiotherapy (3DCRT) or intensity modulated radiotherapy (IMRT) boost,1 was treated as second-course radiotherapy,and others were treated with cyberknife only.The survival rates were calculated by Kaplan-Meier method and compared with Logrank test.ResultsThe complete response,partial response,stable disease and progression disease rates were 43％(12/28),6％ ( 10/28),18％ ( 5/28 ),4％ ( 1/28 ),respectively.The overall response rate was 96％.The number of patients who were followed up more than 1,2,3 years were 17,9,7,respectively.The 1-,2-and 3-year local control rates were 92％,86％ and 86％,respectively.The 1-,2-and 3-year overall survival rates were 60％,49％ and 49％,respectively.The difference between local progression-free survival and overall survival was not significant ( median 9.5 and 12.0 months,x2 =0.17,P =0.680).Moreover,if the patients did not have metastasis elsewhere and local treatment was effective,there was no significant difference between local progression-free survival and progression free survival (median 17 and 11 months,x2 =0.13,P=0.720).Acute radiation-induced side effects (≥ 2 grade) such as fatigue,anorexia,nausea,vomiting and epigastric discomfort occurred in 9,9,7,7 and 2 patients,respectively.Intestinal stenosis of 1 grade occurred in 1 patient.Conclusions Radiotherapy for retroperitoneal tumors with cyberknife has provided a high response rate with minimal side effects.It is a safe and effective local treatment method for retroperitoneal tumors.

Impact of number of implanted fiducials on image target localization accuracy / 中华放射肿瘤学杂志

Objective To find a proper number of implanted fiducials in order to reconcile both more accurate image tacking and less pain for the patients.Methods The phantom was made of two parts of different materials.The inner part was a ball-cube phantom developed by Accuray Corporation, which could be regarded as a rigid body, with 5 fiducials inside using as the reference to align the whole phantom in the experiment.The outer part was made of additional silicone rubber with two components to simulate soft tissue as a non-rigid body, which was implanted with 8 fiducials inside.All combinations of different number of fiducials were tracked to aquire the target location information, which were then compared with the reference position that was set by the inner 5 fiducials to obtain the deviations of the translation and the rotation parameters.Thus the impact of the number of fiducials on image target localization accuracy could be analyzed easily.Results When 4 fiducials are used for tracking, the decline of translation and rotation errors for every fiducial is largest (0.086 mm and 0.033°).The translation error was decreased by 0.343 mm from 1 to 4 fiducials, while by only 0.077 mm from 4 to 8 fiducials;the same decline was observed for rotation errors (0.131° for 3 to 4 fiducials , and 0.09° for 4 to 8 fiducials , respectively) .Conclusions When 4 fiducials are used for tracking, the decline of errors for every fiducial is maximum.When one more fiducial is adding, the image target localization accuracy can be enhanced obviously from 1 to 4 fiducials, but not as obvious for more than 4 fiducials.