A Novel Tracheobronchial Stent Loaded with 125I Seeds in Patients with Malignant Airway Obstruction Compared to a Conventional Stent: A Prospective Randomized Controlled Study

Treatment of malignant airway obstruction with Y-shape sigma stent loaded with I125 seeds installed via rigid bronchoscopy

PURPOSE

To summarize and analyze the safety and efficacy of a Y-shape Sigma stent loaded with I125 in patients with inoperable malignant main airway obstruction.

METHODS

This study was approved by the Institutional Ethics Committee, and a written informed consent was obtained from each participant. A Y-shape Sigma stent loaded with I125 was placed under vision from rigid bronchoscopy. The primary endpoint was alleviation of symptoms and improvement of Karnofsky Performance Status (KPS) score, and the secondary endpoint was complications and technical success.

RESULTS

From November 2018 through June 2023, total 33 patients with malignant airway obstruction were palliatively treated by installing Y-shape Sigma stents loaded with I125. The airway lumen was immediately restored and the average airway opening significantly increased to 70 ± 9.4% after the procedure from baseline 30.2 ± 10.5% (p < 0.05). Average KPS score was improved from baseline 30.0 ± 10.0 to 70.0 ± 10.0 (p < 0.05) as well as PaO2 from baseline 50.1 ± 15.4 mmHg to 89.3 ± 8.6 mmHg (p < 0.05). The technical success rate of placing the stent in this study was 73%, and adverse events or complications including bleeding, I125 loss, and airway infection occurred during or after the procedure.

CONCLUSION

Placement of Y-shape Sigma stents under vision from rigid bronchoscopy in the patients with malignant airway obstruction is feasible and it immediately alleviates dyspnea and significantly improves quality of life.

Recent progress in radioactive seed implantation brachytherapy of non-small cell lung cancer: a narrative review

Background and Objective

Brachytherapy, a new form of radiation therapy, has been used to treat lung cancer and consists of two main forms of treatment: endobronchial brachytherapy and radioactive seed implantation brachytherapy (RSI-BT), the latter of which is used to treat non-small cell lung cancer (NSCLC). The use of RSI-BT in the treatment of NSCLC at our centre has yielded some positive results.

Methods

To more fully consider the context of this application, we conducted a search of PubMed from 2018 to March 5, 2023. The search included a combination of the MeSH terms: "brachytherapy" and "lung neoplasm".

Key Content and Findings

The majority of NSCLC patients who received RSI-BT achieved positive benefits. Most patients had a progression-free survival (PFS) of between 12 and 18 months. Additionally, radioactive particle stent implantation as a specific RSI-BT has shown therapeutic potential in the treatment of malignant airway obstruction. With the application of new technologies, RSI-BT will become more precise, efficient and inexpensive.

Conclusions

This review demonstrates that RSI-BT can be therapeutic in the treatment of both early and advanced NSCLC with manageable complications. There have also been reports on the combination of RSI-BT with other therapies, but more research is needed on the combination of RSI-BT with them.

Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

Transarterial infusion chemotherapy for advanced esophageal cancer with airway stenosis

Purpose

This study aimed to investigate the safety and efficacy of transarterial infusion chemotherapy for the treatment of esophageal cancer with airway stenosis.

Methods

Data of patients with advanced esophageal cancer complicated with airway stenosis treated with transarterial infusion chemotherapy were retrospectively analyzed. Dyspnea, clinical efficacy and adverse reactions were evaluated.

Results

Of these patients, 27 had grade II preoperative dyspnea, and 31 had grade III preoperative dyspnea, 26 had grade I postoperative dyspnea, 25 had grade II postoperative dyspnea, and 7 had grade III postoperative dyspnea. Among 3 patients with left main bronchial stenosis and atelectasis, 2 had complete remission after transarterial infusion chemotherapy, and 1 demonstrated partial remission. After treatment, complete response, partial response, and stable disease were observed in 7, 34, and 17 cases, respectively. Total objective effective rate and disease control rate were 70.6% (41/58) and 100.0%, respectively. During follow up, 24 patients died of organ failure, and 17 patients died of tumor-related respiratory failure. Seven patients died of gastrointestinal bleeding, 1 patient died of myocardial infarction, and 9 patients survived.

Conclusions

Transarterial infusion chemotherapy is safe and effective for the treatment of advanced esophageal cancer with airway stenosis.

Irradiation stent with 125 I plus TACE versus sorafenib plus TACE for hepatocellular carcinoma with major portal vein tumor thrombosis: a multicenter randomized trial

BACKGROUND AND AIM

Treatment strategy for hepatocellular carcinoma (HCC) and Vp4 [main trunk] portal vein tumor thrombosis (PVTT) remains limited due to posttreatment liver failure. We aimed to assess the efficacy of irradiation stent placement with 125 I plus transcatheter arterial chemoembolization (TACE) (ISP-TACE) compared to sorafenib plus TACE (Sora-TACE) in these patients.

METHODS

In this multicenter randomized controlled trial, participants with HCC and Vp4 PVTT without extrahepatic metastases were enrolled from November 2018 to July 2021 at 16 medical centers. The primary endpoint was overall survival (OS). The secondary endpoints were hepatic function, time to symptomatic progression, patency of portal vein, disease control rate, and treatment safety.

RESULTS

Of 105 randomized participants, 51 were assigned to the ISP-TACE group, and 54 were assigned to the Sora-TACE group. The median OS was 9.9 months versus 6.3 months (95% CI: 0.27-0.82; P =0.01). Incidence of acute hepatic decompensation was 16% (8 of 51) versus 33% (18 of 54) ( P =0.036). The time to symptomatic progression was 6.6 months versus 4.2 months (95% CI: 0.38-0.93; P =0.037). The median stent patency was 7.2 months (interquartile range, 4.7-9.3) in the ISP-TACE group. The disease control rate was 86% (44 of 51) versus 67% (36 of 54) ( P =0.018). Incidences of adverse events at least grade 3 were comparable between the safety populations of the two groups: 16 of 49 (33%) versus 18 of 50 (36%) ( P =0.73).

CONCLUSION

Irradiation stent placement plus TACE showed superior results compared with sorafenib plus TACE in prolonging OS in patients with HCC and Vp4 PVTT.

Stent loaded with radioactive Iodine-125 seeds for adenoid cystic carcinoma of central airway: A case report of innovative brachytherapy

Adenoid cystic carcinoma (ACC) of central airway is very rare. More than half of ACCs are unresectable for tumor extension. There’s rare report on local ACCs only in central airway. We present a case of ACC in central airway who underwent an innovative brachytherapy. A 44-year-old woman was diagnosed with primary ACC in central airway without regional lymphadenopathy or metastatic disease. Stenosis was observed in lower trachea and both left and right main bronchi (stenosis in lumen ≥50%) with bronchoscopy. The tumor was unresectable due to local extension. A Y-shaped and stainless-steel stent loaded with radioactive 125I seeds was placed in the central airway using bronchoscope. The number and distribution of 125I seeds were planed using treatment planning system. The stent was removed three months later. The patient tolerated the procedure well. She was alive without relapse three years after removing the stent with 125I seeds. This case demonstrates the successful use of stent with radioactive 125I seeds for unresectable ACCs in central airway. In the procedure, the stent was placed with bronchoscope and under the vision from bronchoscope. This innovative brachytherapy is well-tolerated, safe, precise and individualized designed. The patient with unresectable ACCs could get a long-term relapse-free survival. Clinical trials could be taken to validate its effectiveness and tolerability in patients with ACCs of central airway.

Establishing a novel model of malignant airway stenosis in rabbit

Background

Malignant central airway stenosis is a life-threatening condition. However, treatment of malignant airway stenosis remains challenging. There is currently a severe lack of an excellent animal model of malignant airway stenosis to facilitate treatment approaches. This is the first study to establish a rabbit model of malignant airway stenosis for bronchoscopic interventional studies.

Materials and methods

New Zealand White rabbits were used in this study, randomly divided into group A (18 rabbits) and group B (6 rabbits). A VX2 fragment suspension was injected into the submucosal layer of rabbits’ airway by bronchoscopy. Bronchoscopic examinations were performed once a week after VX2 tumor implantation to observe tumor growth and the degree of airway stenosis. Randomly, three rabbits were generally dissected after a weekly bronchoscopic examination in group A. The rabbits that reached grade III airway stenosis underwent stent implantation in group B.

Results

A total of 24 rabbits were successfully implanted with the VX2 fragment suspension in the airway without significant adverse events, and the success rate of the tumor growth was 100%. The degree of airway stenosis reaching grade III took 2 to 3 weeks after implantation of the VX2 tumor. The median survival time of rabbit models without stent implantation and rabbits with stent implantation was 32.5 and 32.0 days, respectively.

Conclusions

The implanting method is safe and effective for the establishment of a rabbit model of malignant airway stenosis. When the tumor grows to 2 to 3 weeks, the rabbit model is available for stent implantation. We recommend the models for more preclinical animal studies on bronchoscopic interventional treatments.

Malignant Central Airway Obstruction: What's New?

Malignant central airway obstruction (MCAO) is a debilitating and life-limiting complication that occurs in an unfortunately large number of individuals with advanced intrathoracic cancer. Although the management of MCAO is multimodal and interdisciplinary, the task of providing patients with prompt palliation falls increasingly on the shoulders of interventional pulmonologists. While a variety of tools and techniques are available for the management of malignant obstructive lesions, advancements and evolution in this therapeutic venue have been somewhat sluggish and limited when compared with other branches of interventional pulmonary medicine (e.g., the early diagnosis of peripheral lung nodules). Indeed, one pragmatic, albeit somewhat uncharitable, reading of this article's title might suggest a wry smile and shug of the shoulders as to imply that relatively little has changed in recent years. That said, the spectrum of interventions for MCAO continues to expand, even if at a less impressive clip. Herein, we present on MCAO and its endoscopic and nonendoscopic management-that which is old, that which is new, and that which is still on the horizon.

Intestinal stents: Structure, functionalization and advanced engineering innovation

Intestinal stents are a palliative treatment option that solves many shortcomings of traditional surgeries for cancer-induced intestinal obstructions. The present review provides an overview of the incidence, clinical manifestations and limitations in the treatment of intestinal cancers. The paper also discusses material property requirements, indications, complications and the future of stent-assisted therapy. The advantages and disadvantages of different materials and processing techniques for intestinal stents are reviewed along with new stent treatment combinations for colorectal cancer. Challenges that require further cooperative studies are also detailed. The future development of intestinal stents will depend on innovation in material designs as well as the utilization of multi-functional strategies and innovative engineering solutions.

Animal study of a newly designed metal airway brachytherapy stent loaded with radioactive 125I seeds

AIM

To evaluate dynamic tissue changes after airway stenting (AS) with a newly designed metal brachytherapy stent (BS) loaded with radioactive ¹²⁵I seeds in normal rabbits.

METHODS

Forty-five normal New Zealand white rabbits were divided into 3 groups (group A: stent without seeds; group B: stent with 0.4 mCi active seeds; group C: stent with 0.8 mCi active seeds) and underwent AS under C-arm guidance. Then, five rabbits were killed from each group at 2, 4, and 8 weeks for further examination. Laboratory tests (including routine blood tests, liver function, kidney function, and electrolytes), gross observations, and tissue changes of Masson/hematoxylin-eosin staining, plus immunohistochemistry of α-SMA, NOX4, and TGF-β were performed at each time point.

RESULTS

All animals underwent AS successfully without procedure-related death, but one animal died at 6 weeks due to severe pulmonary infection in group C. Apart from a transient increase in white blood cells (P < 0.05) and a gradual increase in ROS levels (P < 0.05), other blood test items showed no significant changes (P > 0.05). The brachytherapy injury score increased with irradiation dose accumulation (P < 0.05), but tissue hyperplasia at the stent end in group C was less severe than that in groups A and B (P < 0.05). Airway lateral fibrosis was observed in all groups by histopathologic analysis; however, fibrosis in group C was more severe than that in groups A and B (P < 0.05).

CONCLUSION

The brachytherapy injury score increased with irradiation dose accumulation, while granulation tissue hyperplasia at the stent end was inhibited by ¹²⁵I brachytherapy within 8 weeks.

Current practices in the management of central airway obstruction

PURPOSE OF REVIEW

Airway obstruction continues to cause substantial pulmonary morbidity and mortality. We present a review of classic, current, and evolving management techniques, highlighting recently published studies on the topic. Recommendations have historically been primarily based on anecdotal experience, case reports, and retrospective studies, but more solid evidence has emerged in the last decade.

RECENT FINDINGS

Novel endobronchial stents are being developed to mitigate the issues of stent migration, mucus plugging, fracture, and granulation tissue formation. Endobronchial drug delivery has become an active area of translational and clinical research, especially with regards to antineoplastic agents used for malignant airway stenosis. Even classic or updated techniques such as spray cryotherapy, injections of mitomycin-c, and balloon dilation have recently been examined in methodologically sound studies. Finally, recently published data have confirmed that patient breathlessness and quality of life improve significantly with therapeutic airway interventions. A multimodal and multidisciplinary approach to patient care is key to achieving the best outcomes.

SUMMARY

The treatment of central airway stenosis is often multimodal and should focus on patient-centric factors, taking into account risks and benefits of the procedure, operator, and center expertise, and always occur in the context of a multidisciplinary approach. Evidence-based clinical research is increasingly driving patient management.

Antibiotic-metal complexes in wastewaters: fate and treatment trajectory

Unregulated usage, improper disposal, and leakage from pharmaceutical use and manufacturing sites have led to high detection levels of antibiotic residues in wastewater and surface water. The existing water treatment technologies are insufficient for removing trace antibiotics and these residual antibiotics tend to interact with co-existing metal ions and form antibiotic-metal complexes (AMCs) with altered bioactivity profile and physicochemical properties. Typically, antibiotics, including tetracyclines, fluoroquinolones, and sulphonamides, interact with heavy metals such as Fe²⁺, Co²⁺, Cu²⁺, Ni²⁺, to form AMCs which are more persistent and toxic than parent compounds. Although many studies have reported antibiotics detection, determination, distribution and risks associated with their environmental persistence, very few investigations are published on understanding the chemistry of these complexes in the wastewater and sludge matrix. This review, therefore, summarizes the structural features of both antibiotics and metals that facilitate complexation in wastewater. Further, this work critically appraises the treatment methods employed for antibiotic removal, individually and combined with metals, highlights the knowledge gaps, and delineates future perspectives for their treatment.

Radioactive Iodine-125 in Tumor Therapy: Advances and Future Directions

Radioactive iodine-125 (I-125) is the most widely used radioactive sealed source for interstitial permanent brachytherapy (BT). BT has the exceptional ability to deliver extremely high doses that external beam radiotherapy (EBRT) could never achieve within treated lesions, with the added benefit that doses drop off rapidly outside the target lesion by minimizing the exposure of uninvolved surrounding normal tissue. Spurred by multiple biological and technological advances, BT application has experienced substantial alteration over the past few decades. The procedure of I-125 radioactive seed implantation evolved from ultrasound guidance to computed tomography guidance. Compellingly, the creative introduction of 3D-printed individual templates, BT treatment planning systems, and artificial intelligence navigator systems remarkably increased the accuracy of I-125 BT and individualized I-125 ablative radiotherapy. Of note, utilizing I-125 to treat carcinoma in hollow cavity organs was enabled by the utility of self-expandable metal stents (SEMSs). Initially, I-125 BT was only used in the treatment of rare tumors. However, an increasing number of clinical trials upheld the efficacy and safety of I-125 BT in almost all tumors. Therefore, this study aims to summarize the recent advances of I-125 BT in cancer therapy, which cover experimental research to clinical investigations, including the development of novel techniques. This review also raises unanswered questions that may prompt future clinical trials and experimental work.

Technical note: A fast and accurate analytical dose calculation algorithm for 125 I seed-loaded stent applications

PURPOSE

The safety and clinical efficacy of ¹²⁵ I seed-loaded stent for the treatment of portal vein tumor thrombosis (PVTT) have been shown. Accurate and fast dose calculation of the ¹²⁵ I seeds with the presence of the stent is necessary for the plan optimization and evaluation. However, the dosimetric characteristics of the seed-loaded stents remain unclear and there is no fast dose calculation technique available. This paper aims to explore a fast and accurate analytical dose calculation method based on Monte Carlo (MC) dose calculation, which takes into account the effect of stent and tissue inhomogeneity.

METHODS

A detailed model of the seed-loaded stent was developed using 3D modeling software and subsequently used in MC simulations to calculate the dose distribution around the stent. The dose perturbation caused by the presence of the stent was analyzed, and dose perturbation kernels (DPKs) were derived and stored for future use. Then, the dose calculation method from AAPM TG-43 was adapted by integrating the DPK and appropriate inhomogeneity correction factors (ICF) to calculate dose distributions analytically. To validate the proposed method, several comparisons were performed with other methods in water phantom and voxelized CT phantoms for three patients.

RESULTS

The stent has a considerable dosimetric effect reducing the dose up to 47.2% for single-seed stent and 11.9%-16.1% for 16-seed stent. In a water phantom, dose distributions from MC simulations and TG-43-DP-ICF showed a good agreement with the relative error less than 3.3%. In voxelized CT phantoms, taking MC results as the reference, the relative errors of TG-43 method can be up to 33%, while those of TG-43-DP-ICF method were less than 5%. For a dose matrix with 256 × 256 × 46 grid (corresponding to a phantom of 17.2 × 17.2 × 11.5 cm³ ) for 16-seed-loaded stent, it only takes 17 s for TG-43-DP-ICF to compute, compared to 25 h for the full MC calculation.

CONCLUSIONS

The combination of DPK and inhomogeneity corrections is an effective approach to handle both the presence of stent and tissue heterogeneity. Exhibiting good agreement with MC calculation and computational efficiency, the proposed TG-43-DP-ICF method is adequate for dose evaluation and optimization in seed-loaded stent implantation treatment planning.

Radioactive and normal stent insertion for the treatment of malignant airway stenosis: A meta-analysis

PURPOSE

To demonstrate the advantage of radioactive stent (RS) for treating malignant airway stenosis (MAS) in reducing the stent restenosis rate and increasing overall survival (OS).

MATERIALS AND METHODS

Relevant studies in Pubmed, Embase, and Cochrane Library databases were identified. The rate of stent restenosis was the primary endpoint, whereas secondary endpoints were rates of stent-related complications, OS, and complete relief of dyspnea. This meta-analysis was conducted using RevMan v5.3.

RESULTS

Five total studies including 131 and 119 patients that underwent RS and normal stent (NS) insertion, respectively, were identified and included in this meta-analysis. Four studies were randomized controlled trials and one study was retrospective study. Pooled rates of complete relief of dyspnea, chest pain, hemoptysis, and fistula formation were similar between these two groups (p = 0.72, 0.77, 0.92, and 0.62, respectively). Pooled Δstenosis grade was comparable between these two groups (p = 0.72). RS insertion was linked to a significant lower pooled stent restenosis rate, increased OS, and higher 3-month survival rate relative to NS insertion (p< 0.00001, 0.0001, and 0.03, respectively). Pooled 6-months survival rates was higher in RS group without significant difference (p = 0.06). Pooled stent restenosis rate was significant higher in RS group based on each subgroup analysis. No evidence of publication bias for these endpoints was detected via funnel plot.

CONCLUSIONS

This meta-analysis revealed that RS insertion was sufficient to reduce rates of stent restenosis and to prolong patient OS relative to NS insertion when used to treat MAS.

Brachytherapy for lung cancer

Brachytherapy (BT) is a minimally invasive anticancer radiotherapeutic modality where the tumor is directly irradiated via a radioactive source that is precisely implanted in or adjacent to the tumor. BT for lung cancer may be conducted in the form of endobronchial BT and radioactive seed implantation (RSI-BT), mainly for nonsmall cell lung cancer (NSCLC). For patients with early-stage lung cancer who are not suitable for surgery or external beam radiotherapy (EBRT), BT may be used as an alternative treatment, and curative results could be achieved in certain patients with cancer confined to the trachea lumen. For patients with locally advanced/metastatic lung cancer, BT could be selectively applied alone or as a boost to EBRT, which could improve the local tumor control and patient's survival. In addition, BT is also useful as a salvage treatment in select patients with locally recurrent/residual lung cancer that failed other treatments (e.g., surgery, chemotherapy, and EBRT). However, clinical outcomes are mainly obtained from retrospective studies. Prospective studies are limited and needed. In recent years, the introduction of modern image guidance, novel radioactive seeds, BT treatment planning systems (BT-TPS), after-loading technique, and three-dimensional printing template (3D-PT) assistance, among others, have potentially improved the clinical outcomes of BT. However, a comprehensive review of BT with newly published literature was lacking. This review is to discuss BT for NSCLC based on recent literature published in PubMed.

Computed tomography-guided implantation of 125I radioactive seeds in patients with malignant airway compression induced by advanced lung cancer: effectiveness and safety in 40 patients

Purpose

To evaluate the safety and efficacy of computed tomography (CT)-guided ¹²⁵I radioactive seed implantation in patients with malignant airway compression induced by advanced lung cancer.

Material and methods

Between June 2015 and June 2018, 40 patients from three medical institutions with malignant airway compression induced by advanced lung cancer were treated with ¹²⁵I seed implantation. The outcomes were measured in technical success and safety, objective response rate, complications, Karnofsky performance status (KPS) score, and survival time.

Results

All 40 patients successfully underwent implantation procedure. No procedure-associated death occurred. The most common complications were irritable cough, temporary hemoptysis, chest pain, fever, and pneumothorax, which occurred in 26 (65.0%), 31 (77.5%), 12 (30.0%), 15 (37.5%), and 11 (27.5%) patients, respectively. The objective response rates were 100%, 100%, 100%, 87.5%, and 83.3% at the 3^rd, 6^th, 12^th, 24^th, and 36^th months post-procedure, respectively. The KPS score significantly improved at post-procedure. Median survival time was 25.1 months. Actuarial survival rates were 100%, 60%, and 15% at the 12^th, 24^th, and 36^th months after the procedure, respectively.

Conclusions

For patients with malignant airway compression induced by advanced lung cancer, implantation with ¹²⁵I seed is a safe and effective alternative treatment option.

Endovascular Treatment of Cancer-Associated Venous Obstruction: Comparison of Efficacy Between Stent Alone and Stent Combined With Linear Radioactive Seeds Strand

OBJECTIVES

To investigate the safety and efficacy of a stent combined with a linear strand of ¹²⁵I seeds to treat malignant cancer-associated venous obstruction.

METHODS

We retrospectively analyzed the data of 57 patients with malignant cancer-associated venous obstruction. Nineteen patients underwent the placement of a stent combined with a linear strand of ¹²⁵I seeds (group A), and 38 patients underwent the placement of a bare stent (group B). The following parameters were compared between the 2 groups of patients: symptom relief rate, duration of venous patency, survival time, quality of life, and adverse events.

RESULTS

A total of 34 stents and 527 seeds were implanted in group A, while a total of 57 stents were implanted in group B. The surgery success rate was 96.5%, and no serious complication related to the surgery was reported. Symptoms of venous obstruction improved significantly after surgery. The score of group A decreased from 14.74 ± 0.562 points before surgery to 2.79 ± 1.357 points after surgery(P < .001), and the score of group B decreased from 13.79 ± 1.398 points before surgery to 5.55 ± 3.674 points after surgery (P < .001). The patency rate of group A was significantly higher than that of group B at 1 to 6 months after surgery (100%, 84.2%, 68.4%, 63.2%, 36.8%, 21.1% vs 68.4%, 23.7%, 18.4%, 7.9%, 5.3%, 2.6%, respectively; P < .05). Before treatment, there was no statistically significant difference in the Karnofsky Performance Status (KPS) score between the groups (P = .791). After 1 to 6 months of treatment, the KPS score was significantly higher in group A than in group B (P = .013). The median patency duration in groups A and B was 125 days (95% CI: 80.018-169.982) and 35 days (95% CI: 20.501-49.499), respectively (P < .001). The median survival time of group A was 155 days (95% CI: 110.406-199.594), and that of group B was 98 days (95% CI: 55.712-140.288; P = .325). Multivariate analysis showed that the implantation of a stent combined with a linear strand of ¹²⁵I seeds and the KPS score (≥80 points) were independent factors of long-term patency after stent placement.

CONCLUSIONS

The placement of a stent combined with a linear strand of ¹²⁵I seeds is a safe and effective treatment for venous obstruction caused by malignant tumors. This treatment provides prolonged patency compared with the placement of bare stent, and while it does not significantly improve the survival time of patients, it can improve their quality of life.

The efficacy of the combination of percutaneous transhepatic biliary drainage and 125I stranded seeds for malignant bile duct obstruction treatment

Purpose

To investigate the efficacy of percutaneous transhepatic biliary drainage (PTBD) combined with iodine-125 (¹²⁵I) stranded seeds for the treatment of malignant bile duct obstruction (MBO).

Material and methods

A retrospective study was performed on 58 consecutive MBO patients. Twenty patients underwent PTBD combined with ¹²⁵I stranded seeds (group A). Thirty-eight patients underwent percutaneous trans-hepatic biliary drainage (group B). Total bilirubin, direct bilirubin, and indirect bilirubin levels were compared preoperatively, 1-week, 1-month, and 3-months post-operatively. Carbohydrate antigen 19-9 (CA19-9), cancer antigen 125 (CA125), and carcino-embryonic antigen (CEA) levels were compared at preoperative and 3-month post-operative stages. The time free from biliary obstruction and survival times were compared.

Results

The differences in total bilirubin, direct bilirubin, and indirect bilirubin levels between the two groups were not significant preoperatively (p = 0.857, p = 0.719, and p = 0.870), and 1-week post-operatively (p = 0.259, p = 0.395, and p = 0.145). However, 1-month (p = 0.012, p = 0.005, and p = 0.049) and 3-months post-operatively (p < 0.001, p = 0.001, and p = 0.001), group A was lower than group B. Differences in CA19-9, CA125, and CEA levels between the two groups were not significant preoperatively (p = 0.229, p = 0.116, and p = 0.273) and 3-months post-operatively (p = 0.159, p = 0.342, and p = 0.306). The median biliary obstruction free time was 7.0 months for group A and 5.0 months for group B (p < 0.001). The median survival time was 9.0 months for group A and 6.0 months for group B (p = 0.001).

Conclusions

PTBD combined with ¹²⁵I stranded seeds seem to reduce bilirubin levels and prevents biliary obstruction, promoting survival.

Radiomics Facilitates Candidate Selection for Irradiation Stents Among Patients With Unresectable Pancreatic Cancer

Purpose: To develop a model to select appropriate candidates for irradiation stent placement among patients with unresectable pancreatic cancer with malignant biliary obstruction (UPC-MBO). Methods: This retrospective study included 106 patients treated with an irradiation stent for UPC-MBO. These patients were randomly divided into a training group (74 patients) and a validation group (32 patients). A clinical model for predicting restenosis-free survival (RFS) was developed with clinical predictors selected by univariate and multivariate analyses. After integrating the radiomics signature, a combined model was constructed to predict RFS. The predictive performance was evaluated with the concordance index (C-index) in both the training and validation groups. The median risk score of progression in the training group was used to divide patients into high- and low-risk subgroups. Results: Radiomics features were integrated with clinical predictors to develop a combined model. The predictive performance was better in the combined model (C-index, 0.791 and 0.779 in the training and validation groups, respectively) than in the clinical model (C-index, 0.673 and 0.667 in the training and validation groups, respectively). According to the median risk score of 1.264, the RFS was significantly different between the high- and low-risk groups (p < 0.001 for the training group, and p = 0.016 for the validation group). Conclusions: The radiomics-based model had good performance for RFS prediction in patients with UPC-MBO who received an irradiation stent. Patients with slow progression should consider undergoing irradiation stent placement for a longer RFS.

Dose perturbation and inhomogeneity of multi-arrays of 125I seed-loaded stent for treatment of portal vein tumor thrombosis

PURPOSE

To investigate the dosimetry of ¹²⁵I seed-loaded stent system currently used for an adjuvant treatment of portal vein tumor thrombosis (PVTT).

METHODS

The stent system consisted of an inner metallic stent and outer seed-loaded capsules. Four arrays of ¹²⁵I seeds were attached longitudinally to the outer surface of the stent at 90° separation. 145 Gy was prescribed at 5 mm from the axes of seed-arrays. For the geometries of the 4-array, and potential 6- and 8-array configurations, treatment planning system (TPS) and Monte Carlo (MC) calculations were performed to evaluate 3D dose distributions and dosimetric impact of the metallic stent.

RESULTS

The MC simulations indicated the metallic stent reduced a dose to the prescription points by over 10%, compared to the water-based TPS results. The total activity calculated by the water-based TPS to deliver the prescription dose should compensate for this amount of reduction. The MC- and TPS-calculated doses normalized to the prescription points for the current configuration were in agreements within 4.3% on a cylindrical surface along 5 mm from the axes of seed-arrays. The longitudinal underdosage worsened as approaching the edge of arrays, and ranged from 2.8% to 25.5%. The angular underdosage between neighboring arrays was 2.1%-8.9%.

CONCLUSIONS

With this compensation and a special care of near-edge underdosage, the current 4-array system can provide adequate dose coverage for treatment of PVTT. Further dosimetric homogeneity can be achieved using 6-or 8-array configurations.