Clinical Research On ¹²⁵Ⅰ Seed Implantation In Treatment Of Para-aortic Lymph Node Metastasis

Objective: Permanent radioactive ¹²⁵Ⅰ seed interstitial implantation is a lowe dose rate brachytherapy.Compared with External beam radiotherapy（EBRT）,its main advantage is derived from its enhanced conformality and rapid dose falloff to adjacent normal structures because of its inverse square velocity attenuation.Additionally,the characteristics of high pass to linear density,high relative biological effect and low oxygen enhancement ratio,it may improve treatment efficacy.¹²⁵Ⅰ particle implantation has the advantages of minimally invasive,safety,less complications and effectiveness.It has been a gold standard modality in patients with low-risk prostate cancer.It has been widely used in clinical treatment of various kinds of solid tumour and achieved good clinical curative effect,such as lung cancer,pancreatic cancer,liver cancer,and retroperitoneal lymph node metastasis.As the most important approach of lymph node metastasis,retroperitoneal lymph node metastasis probability are 20-40% locally advanced cervical cancer,nearly50% of the patients will eventually happen PALN,and it is the most important factors that affect the prognosis.Intestinal obstruction,abdominal pain or backache,gastrointestinal bleeding are the common symptoms in patients might be related to tumor oppression and retroperitoneal plexus invasion or compression of afferent nerve fibers.PALN dissection is usually challenging,as these are at deep locations surgical resection rate approaches 20%.EBRT is usually limited by the tolerance of the surrounding normal tissues or organs at risk,even though is obviously improved the controlling rate.EBRT often leads to local tissue fibrosis,vascular occlusion and the chemotherapy is inefficiency.Radioactive seed implantation has attracted increasing attention in recent years with PALN,it advantages of improving ratio of gains,safety and effectiveness,and has achieved remarkable effect in clinical.This researchaims to study the efficacy and safety on the treatment of PALN with ¹²⁵Ⅰ seed implantation aims to explore methods and strategies of effective treatment PALN furtherly.Methods: From October 2012 to September 2016,25 patients with PALN underwent ¹²⁵Ⅰ seed implant brachytherapy under CT guidance at Hebei General Hospital.The lymph node were 2.1 8.9 cm in vertical diameter,the diameter <5cm were 52%,and the diameter >5 cm were 48%.The dose was calculated by using computer treatment planning system.7 patients were underwent 3D print tamplate guided ¹²⁵Ⅰ seeds implantation and had been fixed as the position of operation and then performed CT scan.After preplan was designed,the 3D tamplates were printed.The rest were underwent traditional method,Dosimetry verification was performed after operation.The dose related parameters including D90,V90 were compared between pre and post operation.The postoperation V90 values of the two groups were also compared.To observe the lesion size changes,Karnofsky score（KPS）,numeric rating scales（NRS）and complications of postoperative.Kaplan Meier-survival analysis comparison（tumor diameter > 5 cm and < 5 cm）survival differences.Results:Follow-up period for this group of patients was 6–36 months,CR was 7 cases（28%,7/25）,PR was13 cases（52%,13/25）,SD was 4 cases（16%,4/25）,PD was 1 case（4%,1/25）.The 6-month local control rate was96%,the effective rate was 80%,The 6-,12-and 24-month of survival rates was84%,61.3%,34.5%,respectively.KPS rose from（76.0 ± 13.2）to（84.8±8.71）,P = 0.00;NRS reduced from（3.5± 2.8）to（1.0± 1.4）,P = 0.00.KPS and NRS differences were statistically significant（all P < 0.05）.The patients of 3D tamplate pre and post operation D90 were（86.8 ± 9.4）Gy,（82.9± 9.4）Gy,respectively,P = 0.07;V90（94.2% ± 2.9%）,（94.1% ±3.5%）respectively,P = 0.97,the differences had no statistical significance（P > 0.05）.The patients of traditional method pre and post operation D90 were（70.2 ± 12.6）Gy,（65.1± 16.3）Gy,respectively,P = 0.04;V90（94.9%± 2.3%）,（90.0%± 3.1%）respectively,P = 0.00,the difference was statistically significant（all P < 0.05）.The postoperation V90 values of the two groups difference was statistically significant（P < 0.05）（Z = 2.3,P = 0.01）,V150 were（64.3%±5.8%）.1 case died postoperative gastrointestinal bleeding after 6 months,1 patients occurrence diarrhoea after 4 month,1 case was duodenum colon fistula after 1month.No major complications such as massive hemorrhage,intestinal infection,bone marrow suppression and other related to the procedure occurred during the treatment.Conclusions:1 ¹²⁵Ⅰ seed implantation in treatment of para-aortic lymph node metastasis was effective.2 The technology of 3 D template was no difference in major dose parameters and reached the preoperative planning requirements accurately.3 For the treatment of pain of para-aortic lymph node metastasis,¹²⁵Ⅰ seeds implantation had more reliable effect,faster onset of action and less complications,was a feasible and safe local treatment methods.