Investigation of a novel brachytherapy ureteral stent: trial studies on normal beagle dogs

A Functional Stent Encapsulating Radionuclide in Temperature-Memory Spiral Tubes for Malignant Stenosis of Esophageal Cancer

Stent implantation is a commonly used palliative treatment for alleviating stenosis in advanced esophageal cancer. However, tissue proliferation induced by stent implantation and continuous tumor growth can easily lead to restenosis. Therefore, functional stents are required to relieve stenosis while inhibiting tissue proliferation and tumor growth, thereby extending the patency. Currently, no ideal functional stents are available. Here, iodine-125 (125 I) nuclides are encapsulated into a nickel-titanium alloy (NiTi) tube to develop a novel temperature-memory spiral radionuclide stent (TSRS). It has the characteristics of temperature-memory, no cold regions at the end of the stent, and a uniform spatial dose distribution. Cell-viability experiments reveal that the TSRS can reduce the proliferation of fibroblasts and tumor cells. TSRS implantation is feasible and safe, has no significant systemic radiotoxicity, and can inhibit in-stent and edge stenosis caused by stent-induced tissue proliferation in healthy rabbits. Moreover, TSRS can improve malignant stenosis and luminal patency resulting from continuous tumor growth in a VX2 esophageal cancer model. As a functional stent, the TSRS combines the excellent properties of NiTi with brachytherapy of the 125 I nuclide and will make significant contributions to the treatment of malignant esophageal stenosis.

Clinical outcomes of intraluminal Iodine-125 seed strand brachytherapy and percutaneous nephrostomy in patients with ureteral carcinoma

BACKGROUND

We aimed to evaluate the safety and efficacy of intraluminal iodine-125 seed strand brachytherapy and percutaneous nephrostomy in patients with ureteral carcinoma.

METHODS

From January 2014 to January 2023, 48 patients with ureteral cancer not suitable for surgical resection were enrolled. Iodine-125 seed strand was inserted in 26 patients under c-arm CT and fluoroscopic guidance (Group A), and 22 patients underwent percutaneous nephrostomy without seed strand (Group B). The clinical outcomes (technical success rate, tumor sizes, hydronephrosis Girignon grade, complications, objective response rate (ORR), disease control rate (DCR), and survival time) were evaluated and compared.

RESULTS

A total of 53 seed strands were successfully inserted and replaced in Group A, with a technical success rate of 100%. No procedure-related death or severe complications occurred in both group. Migration of seed strand or drainage tube was the most common complication. The Girignon grade of hydronephrosis was significantly improved 1, 3 and 6 months after procedure in both groups. DCR in Group A were 96.2%, 80.0%, and 70.0% at 1-, 3-, and 6-month follow up, respectively. At 1 and 6 months later, ORR in Group A were significantly higher than those in Group B (p < 0.05). The median overall survival were 30.0 months in Group A and 16.1 months in Group B, respectively (p = 0.04). The median progression-free survival were 11.1 months in Group A and 6.9 months in Group B, respectively (p = 0.09).

CONCLUSION

Intraluminal Iodine-125 seed strand brachytherapy and percutaneous nephrostomy is safe and effective in patients with ureteral carcinoma, with higher ORR and median overall survival than patients underwent percutaneous nephrostomy without seed strand.

Biliary drainage combined with simultaneous 125I seed strand brachytherapy for the treatment of hilar cholangiocarcinoma

BACKGROUND

To evaluate the clinical efficacy of percutaneous biliary drainage (PBD) combined with ¹²⁵I seed strand brachytherapy (ISSB) for the treatment of hilar cholangiocarcinoma (HCCA).

METHODS

The clinical data of 64 patients with HCCA (median age 62.5, male 29, female 35) treated in our department from April 2017 to April 2021 were retrospectively analyzed. Thirty-four patients in the experimental group (EG) were treated with PBD combined with ISSB, while 30 patients in the control group (CG) were treated with PBD alone. The primary study endpoints were technical success, clinical success and the 2-month local tumor control (LTC) rate. Secondary endpoints were early/late complications, median progression-free survival (mPFS) and overall survival (mOS).

RESULTS

The technical and clinical success in the EG and CG showed no significant differences (100 vs. 100%, 94.1 vs. 93.3%, P > 0.05). Both early and late complications showed no significant differences between the two groups (P > 0.05). The 2-month LTC rates were significantly better in the EG versus the CG (94.1% vs. 26.7%, 157.7 ± 115.3 vs. 478.1 ± 235.3 U/ml), respectively (P < 0.05). The mPFS and mOS were 4.3 (95% CI 3.9-4.7) months and 2.8 (95% CI 2.5-3.1) months and 13.5 (95% CI 10.7-16.3) months and 8.8 (95% CI 7.8-9.8) months, respectively, with significant differences (P < 0.05).

CONCLUSION

PBD combined with ISSB is a safe and effective treatment for HCCA that can inhibit local tumors and prolong PFS and OS.

Safety and efficacy of iodine-125 seed strand for intraluminal brachytherapy on ureteral carcinoma

Objective

Our aim is to evaluate the safety and efficacy of iodine-125 seed strand for intraluminal brachytherapy on ureteral carcinoma.

Methods

From November 2014 to November 2021, 22 patients with ureteral cancer not suitable for surgical resection were enrolled. Iodine-125 seed strand was inserted under c-arm CT and fluoroscopic guidance. The technical success rate, complications, disease control rate, and survival time were evaluated. Hydronephrosis Girignon grade and ureteral cancer sizes before and after treatment were compared.

Results

A total of 46 seed strands were successfully inserted and replaced, with a technical success rate of 100% and median procedure time of 62 min. No procedure-related death, ureteral perforation, infection, or severe bleeding occurred. Minor complications were observed in eight (36.4%) patients, and migration of seed strand was the most common complication. Six months after seed strand brachytherapy, one complete response, three partial responses, and five stable diseases were evaluated, and the disease control rate was 64.3%. The Girignon grade of hydronephrosis was significantly improved 1 to 3 months after seed strand insertion. Disease control rates were 94.4, 62.5, and 64.3% at 1-, 3-, and 6-month follow-up. Twenty patients were successfully followed up, with a mean follow-up of 18.0 ± 14.5 months. The median overall survival and progress-free survival were 24.7 and 13.0 months, respectively.

Conclusion

Iodine-125 seed strand is safe and effective for intraluminal brachytherapy and can be used as an alternative to patients with ureteral carcinoma who are not suitable for surgical resection or systemic combined therapy.

Is iodine-125 seed strand brachytherapy suitable for ureteral carcinoma?

BACKGROUND

Long-term conventional high-dose radiation therapy can lead to retroperitoneal fibrosis and nerve damage in patients with advanced ureteral carcinoma (UC). The purpose of this study is to evaluate the safety and efficacy of nephrostomy combined with iodine-125 seed strand (ISS) brachytherapy for the treatment of UC.

MATERIALS AND METHODS

Twenty-one patients with UC were treated with nephrostomy combined with ISS brachytherapy. The following parameters were recorded: technical success rate, procedure time, complications, mean D90 (dose delivered to the 90% gross tumor volume), organ at risk (OAR) dose, local control rate (LCR), ureteral patency (UP), local tumor progression (LTP), and overall survival (OS). The hydronephrosis score (HS), visual analog score (VAS), Karnofsky score and maximum diameter (MD) were compared before and 8 weeks after the operation.

RESULTS

The technical success rate was 100%, with a mean procedure time of 54.6 min. Three cases (14.5%) had bladder implant metastasis but no other major complications, such as ureteral perforation, infection, or severe bleeding, occurred. The mean D90 and OAR doses were 50.7 and 3.8 Gy, respectively. LCR was 100% with 28.6% UP at the 8-week evaluation. During the mean follow-up of 16.6 months, LTP occurred in 4 cases (19.1%), and the median OS was 25.0 months (95% CI 21.3-28.5). The HS, VAS, Karnofsky score and MD showed significant changes (all P < 0.01).

CONCLUSION

UC can be safely and effectively treated by nephrostomy combined with ISS brachytherapy, a viable option for patients who cannot undergo or refuse surgical resection.

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.

Stenting of Malignant Urinary Tract Obstructions in Humans and Companion Animals

Urine retention secondary to neoplastic obstructions of the upper and lower urinary tracts is a life-threatening condition in both humans and companion animals. Stents can be placed to temporarily or permanently open obstructed urinary tract lumens and are often able to be placed using minimally invasive techniques with guidance via ultrasonography or fluoroscopy. The literature for these techniques is vast for humans and growing for companion animals. The below review provides a discussion of the principles of stenting and types of ureteral and urethral stents, as well as the techniques for placing these stents in humans and companion animals.