Retrospective Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 14, 2018; 24(46): 5280-5287
Published online Dec 14, 2018. doi: 10.3748/wjg.v24.i46.5280
Preliminary application of 3D-printed coplanar template for iodine-125 seed implantation therapy in patients with advanced pancreatic cancer
Wei Huang, Jian Lu, Ke-Min Chen, Zhi-Yuan Wu, Qing-Bin Wang, Jing-Jing Liu, Ju Gong, Zhi-Jin Chen, Xiao-Yi Ding, Zhong-Min Wang
Wei Huang, Zhi-Yuan Wu, Qing-Bin Wang, Jing-Jing Liu, Xiao-Yi Ding, Zhong-Min Wang, Department of Interventional Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
Jian Lu, Ju Gong, Zhi-Jin Chen, Department of Radiology, Ruijin Hospital Luwan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai 200020, China
Ke-Min Chen, Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
Author contributions: Wang ZM designed the research and supervised the report; Huang W performed the research and wrote the paper; Chen KM and Ding XY supervised the report; Lu J, Wu ZY, and Wang QB analyzed the data; Liu JJ, Gong J, and Chen ZJ provided clinical advice.
Supported by the National Natural Science Foundation of China, No. 81771949 and No. 81471808; the Project of Medical Key Specialty of Shanghai Municipality, No. ZK2015A22; and the Science and Technology Commission of Shanghai Municipality, No. 18411968600.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of Ruijin Hospital Luwan Branch, Shanghai Jiao Tong University School of Medicine.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent before participating in the study.
Conflict-of-interest statement: None declared.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author to: Zhong-Min Wang, MD, Chief Doctor, Professor, Department of Interventional Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Road, Huangpu District, Shanghai 200025, China.
Telephone: +86-21-64370045-600331 Fax: +86-21-63860461
Received: September 6, 2018
Peer-review started: September 6, 2018
First decision: October 4, 2018
Revised: October 27, 2018
Accepted: November 9, 2018
Article in press: November 9, 2018
Published online: December 14, 2018
Research background

Patients with advanced pancreatic cancer frequently suffer from intractable pain secondary to tumor perineural invasion. This pain can be relieved by traditional external radiotherapy but with significant systemic side effects. To reduce these side effects, in previous studies, radioactive iodine-125 seeds acting as the source of radiation were implanted in pancreatic lesions under computed tomography (CT) guidance, and this approach demonstrated efficacy for local tumor control and pain relief. However, the special location of the pancreas and fragile adjacent organ increase implantation difficulty and lead to inconsistent dosimetric parameters before and after implantation.

Research motivation

3D-printed template is a new iodine-125 seed implantation guidance tool, which can improve implantation accuracy and radiotherapy dosimeters in superficial organs. However, few studies have sufficient information on its application in profound organs, especially the pancreas. As the pancreatic dosimetric parameters are unsatisfactory by using the traditional free hand way, 3D-printed template might be an applicable guidance tool.

Research objectives

The main objective of our study was to evaluate the efficacy and safety of this new guidance tool in the treatment of advanced pancreatic cancer. The preliminary results demonstrated that the procedure is safe and the brachytherapy dosimeters are better in the 3D-printed template group.

Research methods

In this retrospective study, 25 patients with advanced unresectable pancreatic carcinoma were treated with iodine-125 seed implantation. Of these, 12 implantations were assisted by a 3D-printed coplanar template (group A), and the remaining 13 implantations were performed without template guidance and selected as a control group (group B). For group A, the template was made of polymethyl methacrylate (PMMA). Its shape and size were designed and printed based on the entry point and puncture angle. All procedures were performed under CT guidance. The postoperative CT images were sent to TPS to calculate the D90, V90, V100, and V150. For both groups, the dosimetric data were collected and compared. Standard chemotherapy was performed in all patients 1 week after the implantation.

Research results

Iodine-125 seeds were successfully inserted into all pancreatic tumors in groups A and B. For group A, the median pre- and postoperative D90 values were 155.32 ± 8.05 Gy and 154.82 ± 16.43 Gy, respectively; the difference between the values was minimal and not statistically significant (P = 0.91). The postoperative V90, V100, and V150 values were 94.64% ± 2.35%, 91.05% ± 4.06%, and 64.54% ± 13.40%, respectively. Among these, V90 and V100 were slightly lower than planned, and the reasons for this might include the following: (1) altered location and morphology of the pancreatic lesion due to the presence of implantation needles; and (2) the presence of an intratumor necrosis area into which the iodine-125 seeds might migrate due to gravity. Nevertheless, the position of the iodine-125 seeds changed only slightly, and the average postoperative V100 was still greater than 90% and likely did not influence prognosis. The dose of the 3D coplanar template guide group exceeded that of the group B, and the difference was statistically significant (P = 0.00). No major procedure-related complications were observed. For group A, mild hemorrhage was observed in 1 patient with a peritoneal local hematoma duo to mesenteric vein injury.

Research conclusions

According to our study, 3D-printed coplanar template-assisted iodine-125 seed implantation therapy appears to be safe and effective and may improve the implantation accuracy and similarity between the postoperative dosimetric parameters and treatment planning values. 3D-printed coplanar template may be an ideal assistive tool for the iodine-125 seed implantation not only in superficial organs but also in profound organs, e.g., the pancreas.

Research perspectives

The key limitations of our study include the small sample size and short follow-up period. However, the endpoints of the study included dosimeter and safety results. The long-term curative effect and complications associated with this approach will be evaluated in a future case-control prospective study.