Stereotactic brachytherapy using iodine 125 seeds for the treatment of primary and recurrent anaplastic glioma WHO° III

The Chemical Scaffold of Theranostic Radiopharmaceuticals: Radionuclide, Bifunctional Chelator, and Pharmacokinetics Modifying Linker

Therapeutic radiopharmaceuticals have been researched extensively in the last decade as a result of the growing research interest in personalized medicine to improve diagnostic accuracy and intensify intensive therapy while limiting side effects. Radiometal-based drugs are of substantial interest because of their greater versatility for clinical translation compared to non-metal radionuclides. This paper comprehensively discusses various components commonly used as chemical scaffolds to build radiopharmaceutical agents, i.e., radionuclides, pharmacokinetic-modifying linkers, and chelators, whose characteristics are explained and can be used as a guide for the researcher.

Effect of neoadjuvant iodine-125 brachytherapy upon resection of glioma

Background

A more extensive surgical resection of glioma contributes to improved overall survival (OS) and progression-free survival (PFS). However, some patients miss the chance of surgical resection when the tumor involves critical structures.

Purpose

The present study aimed to assess the feasibility of neoadjuvant ¹²⁵I brachytherapy followed by total gross resection for initially inoperable glioma.

Methods

Six patients diagnosed with inoperable glioma due to invasion of eloquent areas, bihemispheric diffusion, or large tumor volume received ¹²⁵I brachytherapy. Surgical resection was performed when the tumor shrank, allowing a safe resection, assessed by the neurosurgeons. Patients were followed up after surgery.

Results

Shrinkage of the tumor after adjuvant ¹²⁵I brachytherapy enabled a total gross resection of all six patients. Four patients were still alive at the last follow-up, with the longest survival time of more than 50 months, two of which returned to everyday life with a KPS of 100. Another two patients had neurological injuries with KPSs of 80 and 50, respectively. One patient with grade II glioma died 34 months, and another with grade IV glioma died 40 months after the combined therapy.

Conclusions

In the present study, the results demonstrated that ¹²⁵I brachytherapy enabled a complete resection of patients with initially unresectable gliomas. ¹²⁵I brachytherapy may offer a proper neoadjuvant therapy method for glioma.

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.

Radiation necrosis after a combination of external beam radiotherapy and iodine-125 brachytherapy in gliomas

PURPOSE

Frequency and risk profile of radiation necrosis (RN) in patients with glioma undergoing either upfront stereotactic brachytherapy (SBT) and additional salvage external beam radiotherapy (EBRT) after tumor recurrence or vice versa remains unknown.

METHODS

Patients with glioma treated with low-activity temporary iodine-125 SBT at the University of Munich between 1999 and 2016 who had either additional upfront or salvage EBRT were included. Biologically effective doses (BED) were calculated. RN was diagnosed using stereotactic biopsy and/or metabolic imaging. The rate of RN was estimated with the Kaplan Meier method. Risk factors were obtained from logistic regression models.

RESULTS

Eighty-six patients (49 male, 37 female, median age 47 years) were included. 38 patients suffered from low-grade and 48 from high-grade glioma. Median follow-up was 15 months after second treatment. Fifty-eight patients received upfront EBRT (median total dose: 60 Gy), and 28 upfront SBT (median reference dose: 54 Gy, median dose rate: 10.0 cGy/h). Median time interval between treatments was 19 months. RN was diagnosed in 8/75 patients. The 1- and 2-year risk of RN was 5.1% and 11.7%, respectively. Tumor volume and irradiation time of SBT, number of implanted seeds, and salvage EBRT were risk factors for RN. Neither of the BED values nor the time interval between both treatments gained prognostic influence.

CONCLUSION

The combination of upfront EBRT and salvage SBT or vice versa is feasible for glioma patients. The risk of RN is mainly determined by the treatment volume but not by the interval between therapies.

Clinical importance of ADC in the prediction of 125I in the treatment for gliomas

Objectives: To determine whether the minimum apparent diffusion coefficient (minADC) value can stratify survival in patients with glioma before ¹²⁵I brachytherapy.

Methods: The study was approved by the Institutional Review Board, and the requirement for informed consent was waived. Twenty-three patients (16 male, 7 female; median age, 48 years) with high-grade glioma (HGG) (n=9) or recurrence after multimodal treatment (n=14) were included in this study. minADC values were obtained before ¹²⁵I implantation. Overall survival (OS) and progression-free survival (PFS) were analyzed with Cox proportional hazards regression models and the Kaplan-Meier method with the log-rank test.

Results: For ¹²⁵I-treated patients, the hazard ratio for OS in patients with ADC≥1.0*10^^-3 mm²·sec^-1 (high minADC) versus ADC<1.0*10^^-3 mm²·sec^-1 (low minADC) was 0.220 (95% confidence interval: 0.066, 0.735). The median OS was 12 months for patients with high minADC values and 6.0 months for those with low minADC values, and the differences were significant (p=0.032). The median PFS was 12 months for patients with high minADC values and 4 months for those with low minADC values. Significant differences were found in the long-rank test (p=0.013). The multivariate analysis results showed that minADC pre-¹²⁵I implantation was an independent predictor of OS and PFS in patients receiving ¹²⁵I brachytherapy.

Conclusions: Pre-¹²⁵I implantation ADC analysis can stratify prognosis in ¹²⁵I-treated patients with glioma, which may aid in choosing a suitable therapy for glioma patients.

Permanent iodine-125 brachytherapy for patients with progressive or recurrent high-grade gliomas

Background

The prognosis of patients with progressive or recurrent high-grade gliomas (HGGs) after surgery remains poor. Iodine-125 brachytherapy is emerging as a salvage method for the treatment of gliomas. This study aimed to investigate whether permanent iodine-125 brachytherapy could be used as an effective therapeutic method even without radiotherapy and/or chemotherapy for progressive or recurrent HGG after gross total resection.

Methods

Between March 2004 and August 2016, 58 patients with progressive or recurrent HGG after gross total resection were included in this study. Twenty-nine patients underwent radiotherapy and/or chemotherapy and then permanent iodine-125 brachytherapy (SRCI group). Twenty-nine patients underwent permanent iodine-125 brachytherapy alone (SI group). Follow-up was carried out at 1, 3, and 6 months and then at 1, 2, 3, and 5 years after iodine-125 implantation. The median overall survival (OS) and progression-free survival (PFS), procedure-related complications and clinical outcomes were evaluated.

Results

No procedure-related fatal events happened. The temporary morbidity rate was 11.9%. The median OS and PFS for patients in the SI group were 22 and 8 months compared with 21 and 7 months in the SRCI group. No significant differences were found. Age and Karnofsky Performance Status (KPS) were independent prognostic factors for OS. Age, KPS and histology were independent prognostic factors for PFS.

Conclusions

Permanent iodine-125 brachytherapy could be used as an effective therapeutic method even without radiotherapy and/or chemotherapy for progressive or recurrent HGG after gross total resection.

A novel three-dimensional template combined with MR-guided 125I brachytherapy for recurrent glioblastoma

Background

At present, the treatment of recurrent glioblastoma is extremely challenging. In this study, we used a novel three-dimensional non-coplanar template (3DNPT) combined with open MR to guide ¹²⁵I seed implantation for recurrent glioblastoma. The aim of this study was to evaluate the feasibility, accuracy, and effectiveness of this technique.

Methods

Twenty-four patients of recurrent glioblastoma underwent 3DNPT with open MR-guided ¹²⁵I brachytherapy from August 2017 to January 2019. Preoperative treatment plan and 3DNPT were made according to enhanced isovoxel T1-weighted MR images. ¹²⁵I seeds were implanted using 3DNPT and 1.0-T open MR imaging guidance. Dosimetry verification was performed after brachytherapy based on postoperative CT/MR fusion images. Preoperative and postoperative dosimetry parameters of D90, V100, V200, conformity index (CI), external index (EI) were compared. The objective response rate (ORR) at 6 months and 1-year survival rate were calculated. Median overall survival (OS) measured from the date of brachytherapy was estimated by Kaplan-Meier method.

Results

There were no significant differences between preoperative and postoperative dosimetry parameters of D90, V100, V200, CI, EI (P > 0.05). The ORR at 6 months was 75.0%. The 1-year survival rate was 58.3%. Median OS was 12.9 months. One case of small amount of epidural hemorrhage occurred during the procedure. There were 3 cases of symptomatic brain edema after brachytherapy treatment, including grade three toxicity in 1 case and grade two toxicity in 2 cases. The three patients were treated with corticosteroid for 2 to 4 weeks. The clinical symptoms related to brain edema were significantly alleviated thereafter.

Conclusions

3DNPT combined with open MR-guided ¹²⁵I brachytherapy for circumscribed recurrent glioblastoma is feasible, effective, and with low risk of complications. Postoperative dosimetry matched the preoperative treatment plan. The described method can be used as a novel implantation technique for ¹²⁵I brachytherapy in the treatment of recurrent gliomas.

Trial registration

The study was approved by the Institutional Review Board of Shandong Provincial Hospital Affiliated to Shandong University (NSFC:NO.2017–058), registered 1st July 2017.

Initial Experience with Intraoperative Phosphorous-32 Brachytherapy During Resection of Malignant Spinal Tumors

INTRODUCTION

Brachytherapy is a major adjuvant modality for neoplasms, but few have trialed its use for spinal tumors. This study examines perioperative and oncologic outcomes of patients with malignant spinal tumors who underwent resection with intraoperative phosphorous-32 (P32) brachytherapy.

METHODS

Consecutive adult patients who underwent P32 brachytherapy during malignant spinal tumor resection were retrospectively identified from 2014 to 2015. Complications, tumor recurrence, and survival were reviewed. A comprehensive review of the literature was performed.

RESULTS

A total of 8 patients were included. Average age was 54.3 years, and 25.0% were males. Tumor types included metastatic leiomyosarcoma, chordoma, multifocal recurrent ependymomas, breast metastasis, malignant meningioma, and myxofibrosarcoma. One-half of patients underwent en bloc tumor resection. P32 plaques were applied to 2 sites per patient for mean 13.1 minutes per site with a goal penetration of 10 Gy to 1-mm depth. Perioperative complications occurred in 3 patients (37.5%), including a persistent cerebral spinal fluid leak, deep infection requiring reoperation, and sacral insufficiency fracture. At a mean 25.6 months follow-up, local recurrence rate was 25.0%, and overall survival was 75.0%. Mean time to recurrence was 14.4 months. Survival at 6, 12, 18, and 24 months was 100.0%, 100.0%, 85.7%, and 71.4%, respectively.

CONCLUSIONS

The use of P32 is safe and feasible. P32 intraoperative brachytherapy does not seem to increase the rate of complications. The sample size of this series is small with heterogeneity in tumor type, but recurrence and survival outcomes seem promising compared with previous reports. Further clinical trials are needed.

CT-guided 125I interstitial brachytherapy for pelvic recurrent cervical carcinoma after radiotherapy

Objective

This retrospective study aimed to evaluate the feasibility, safety, and clinical efficacy of computed tomography (CT)-guided ¹²⁵I seed interstitial brachytherapy for pelvic recurrent cervical cancer in patients with a history of pelvic radiotherapy.

Methods

From March 2011 to December 2015, 35 pelvic recurrent lesions (33 patients) were reirradiated using this type of salvage therapy. The medical history, dose–volume histogram parameters, complications, local control, overall survival (OS), and affected factors were analyzed.

Results

All patients were followed-up until expiration, and the median duration of follow-up was 16 months. The 1-, 3-, 6-, 12-, and 18-month local control rates were 84.5%, 74.2%, 60.0%, 55.5%, and 33.3%, respectively. The symptoms significantly improved after implantation. The median local tumor progression-free survival (LTPFS) and OS times were 7 months (range, 1–19 months) and 12 months (range, 2–42 months), respectively. The 1- and 2-year OS rates were 65.5% and 43.6%, respectively. In univariate analysis, a good performance status, a tumor diameter <4 cm, an interval time from last radiotherapy to seed implantation longer than 6 months and D90 (dose delivered to 90% of the target volume) ≥130 Gy were prognostic factors for LTPFS. Cox proportional hazards regression analysis revealed that tumor size and D90 were independent factors affecting LTPFS (P=0.033, hazard ratio [HR] =3.357, 95% CI =1.105, 10.212; P=0.035, HR =2.766, 95% CI =1.072, 10.212). Good performance status was identified as an independent factor affecting OS (P=0.001, HR =0.086, 95% CI =0.019, 0.387). Two patients showed grade 3–4 toxicity – 1 patient had rectovaginal fistula and 1 patient had incomplete intestinal obstruction – and 3 cases showed seed migration in our analysis. No grade 5 events occurred.

Conclusion

Reirradiation with CT-guided ¹²⁵I seed interstitial brachytherapy is a safe, effective, and minimally invasive method to treat patients with recurrent cervical cancer after radiotherapy.