| Part 1 Comparative Analysis of Efficacy and Safety between 3D-CRT and 125? brachytherapy for the treatment of Metastatic Spinal TumorsSpine is a common site of metastases in malignant tumors,and the treatment of metastatic spinal tumors has drawn more attention these years with the progress of medical diagnosis and treatment technology.Surgery and radiation are two traditional treatments for metastatic spinal tumors,among which conventional radiotherapy is a method of two-dimensional radiotherapy,due to its inability to achieve accurate irradiation on the tumor target area,it has been gradually eliminated by the clinical application.Three-dimensional conformal radiotherapy(3D-CRT)technology is to reconstruct the three-dimensional structure of tumors using CT and other imaging techniques,and to achieve the goal of precise irradiation.At present,3D-CRT technology is mostly used in the treatment of spinal metastases.125?seed implantation was first applied in the treatment of early prostate cancer as a kind of precise brachytherapy.125? seed continues to emit a low energy y-ray with a radiation radius of 1.7cm,and its dosmetric distribution obeys the inverse square law of close distance.Based on this,the dose drops rapidly with distance beyond the treatment target,which is conducive to the protection of the surrounding normal tissues.In recent years,125? brachytherapy has been used in the treatment of spinal metastatic tumors by different researchers,however,the comparative analysis betweent it and 3D-CRT has been rarely reported.ObjectiveThis study aims to study and compare the efficacy and safety of 3D-CRT and 1251 brachytherapy in the treatment of spinal metastatic tumors.Methods1.Samples:the included patients with spinal metastasis in this study were divided into two groups,both of which were confirmed by pathology or cytology as malignant tumors:22 cases with 32 lesions received 125? seed implantation in Shandong provincial hospital between September 2014 and July 2016 were enrolled in group A,and 30 cases with 32 lesions received 3D-CRT in Dezhou peoples' hospital between April 2017 and October 2018 were enrolled in group B.All patients signed the informed consent before treatment.2.Methods:before 125! brachytherapy,all patients in group A received CT scans,and the images were scanned into the Brachytherapy Treatment planning system(BTPS)software,the clinical target volume(CTV)and organ at risk(OAR)were defined and the prescribed dose was 110-130Gy,then dose-volume histogram(DVH)was generated by BTPS.125? seed implantation was completed according to the preoperative plan under the guidance of CT.The procedure for all patients in group B was preplanned on the CT simulator and was administered by 3D-CRT.3.Efficacy and safety evaluation:It was included five parts:pain relief,local tumor control,recovery of nerve function,general physical condition(KPS)and quality of life(QLQ),The adverse reactions of the two groups were also analyzed.Results1.Pain relief:NRS after treatment in both two groups were significantly lower than that before treatment,the rate of pain relief were 96.7%and 93.7%respectively.At the 6-month and 12-month after treatment,NRS of group A was lower than that of group B,and the duration of pain relief in group A was longer than that in gourp B.2.Local tumor control:The local control rates of the two groups at 3,6,12 and 24-month after treatment were 90.6%VS 87.5%,87.5%VS 85.7%,80%VS 77.8%and 66.7%VS 60%respectively,and no statistical differences were found between the two groups.But the number of PR cases in the 125? group was higher than that in the radiotherapy group.3.Evaluation of neurological function:the recovery rate of neurological function were 40%and 41.17%respectively,and there was no statistical difference between the two groups(P=0.22).4.General physical condition:KPS of patients in both groups after treatment was improved than that before treatment.There was no significant difference in KPS difference between the two groups.5.Quality of life:The QLQ scores of patients in both groups after treatment were lower than that before treatment,and the quality of life for both groups were improved.At 6-month and 12-month of follow-up,the QLQ scores of group A were lower than that of group B,which indicated a higher improvement of life quality.6.Safety evaluation:the complications in group A were as follows:13 cases with intraoperative complications,3 cases with radioactive adverse reactions of grade ?-?.11 cases in group B had got radioactive adverse reactions of grade ?-?.All of the complications were resolved after simple management,no case of radiation myelitis was recorded in both groups.ConclusionsBoth 3D-CRT and 125? brachytherapy are safe and effective methods for the treatment of spinal metastatic tumors,125? brachytherapy may have greater advantages in pain relief and improvement of life quality.Part 2 Dosimetric evaluation of 125? brachytherapy in the treatment of spinal metastatic tumorsDosimetry is the basis for the efficacy and safety of radiotherapy.125? seed implantation belongs to brachytherapy,which also requires strict dosimetry control.BTPS provides an important guarantee for the precise implantation of 125?brachytherapy.According to American Brachytherapy Society(ABS),all patients undergoing 125? brachytherapy must have pre-implant treatment plannings in order to provide adequate irradiation on the tumor target area and to reduce radiation damage to surrounding normal tissues,but only the post-implant dose verification is the golden standard for testing the dose distribution of seed implantation.At present,there are few relevant studies on pre-planning and postoperative validation of 125?brachytherapy for spinal metastases,and it lacks standard source distribution and dosimetry specifications.ObjectiveThis study aims to compare the discrepancy between the pre-implant treatment plannings and post-implant dose distributions of 125? seed implantation for spinal metastasis,and to preliminarily explore the relationship between the dosimetric parameters and the therapeutic efficacy.Methods1.Samples:22 cases of spinal metastasis received 125? seed impIantation in Shandong provincial hospital between September 2014 and July 2016 were enrolled in this study,all patients were confirmed by pathology or cytology as malignant tumors.32 vertebral lesions were involved,including 2 cervical metastasis,19 thoracic metastasis,10 lumbar metastasis and 1 sacral metastasis;All lesions haven't received any local treatment such as external radiotherapy,surgery,ablation and so on before 125? implantation2.Lethods:Before 125? brachytherapy,all patients received routine hematology examination,ECG and CT scans,and the images were scanned into BTPS software,the CTV and OAR were defined,and DVH was generated by the BTPS.125? seed implantation was completed under the guidance of CT.CT scan was performed again after the operation,and the areas of insufficient implantation were replanted.3.Post-implant dose verification:CT scan was performed again within one week after the operation,and the images were scanned into BTPS system,the target area was defined and seeds were selected,and then DVH was generated.D90,V100,V150,V200 and the maximum dose of spinal cord(Dmax)was obtained.Three indexes were calculated to evaluate the dose distribution:Cl,HI and EI4.Efficacy evaluation:Local tumor control was defined by the MDA criteria,the rate of local tumor control was defined as(SD+PR+CR)%?Results1.Comparison of pre-planning and postoperative parameters1.1.Comparison of pre-and post-implanting plan-associated parametersPost-implant CTV was a little larger than that of pre-planning(24.81cc VS 24.72cc)with statistical differences(P<0.05),A greater number of needles were used in the pre-implant treatment planning(mean,9)compared with the implantation(mean,6).The number of seeds and the activity per seed were revealed to be similar between the two groups.1.2.Pre-and post-implant dosimetric comparisonsThe mean D90 and V100 in post-implant dosimetry was lower than the pre-implant planning,the Dmax of spinal cord after operation was higher than that in pre-planning.There was no significant difference between V150 and V200.1.3.Comparison of pre-and post-implanting dosimetric distribution parametersCI and HI were lower in post-implant dosimetry(P<0.05),which means that the conformability and uniformity of post-implanting dosimetric distribution haven't met the requirements of pre-planning,and there was no significant difference in El between the two groups.2.Efficacy and safety evaluationThe rates of local tumor control were 90.6%,87.5%,80%and 66.7%respectively at 3,6,12 and 24 months after operation.At the end of follow-up,3 of 22 patients survived,19 patients died,all of whom died of extensive metastases caused by tumor progression.There was no operative related mortality and no radiation myelitis.ConclusionsThe post-implanting dosimetric distribution haven't met the requirements of pre-planning in patients with spinal metastases,but the rate of local tumor control for one year has still reached 80%.Although the Dmax of spinal cord exceeded the limit of external radiotherapy,but no radiation myelitis was observed. |
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