Feasibility and Efficacy of Microwave Ablation Combined with Iodine-125 Seed Implantation in Local Control of Recurrent Retroperitoneal Liposarcomas: Initial Clinical Experience

Experts consensus on 3D-printing template-assisted CT-guided radioactive iodine-125 seed implantation for recurrent soft tissue carcinoma in China

Permanent radioactive iodine-125 seed implantation (RISI), known as radioactive seed implantation, is a minimally invasive internal radiation technique. This method involves implanting 125I seeds (4.5 × 0.8 mm, encapsulated in a nickel-titanium alloy) into tumors under image guidance. The radionuclide continuously releases low energy γ-rays, effectively killing tumor cells. RISI delivers high local doses with minimal damage to surrounding normal tissues. It is performed through image-guided percutaneous puncture, accompanied by high precision, minimal trauma, and rapid recovery. In Western countries, RISI is primarily utilized for early-stage prostate cancer. In 2002, Professor Junjie Wang introduced computed tomography (CT)-guided technology for RISI, expanding its indications to head and neck, thoracic, abdominal, pelvic, and spinal tumors. In 2014, he proposed the concept of image-guided interventional brachytherapy, advancing minimally invasive brachytherapy. In 2015, he integrated three-dimensional 3D-printing template (3D-PT) with CT-guided technology, significantly enhancing the precision, quality, and efficiency of RISI, and introduced the concept of stereotactic brachytherapy. Over nearly 20 years, RISI has developed into a standardized procedure, involving preoperative planning, intraoperative optimization, and postoperative verification, highlighting its role in comprehensive cancer treatment. The main treatments for soft tissue sarcoma (STS) include surgery or surgery combined with radiotherapy and chemotherapy. However, STS is prone to local recurrence, and effective treatments are lacking after recurrence. Experts have conducted extensive trials on RISI for the treatment of recurrent STS (r-STS), accumulating significant clinical experience. This study aimed to establish standards and consensus on 3D-PT-assisted CT-guided RISI for the treatment of r-STS.

Importance of the enhanced cooling system for more spherical ablation zones: Numerical simulation, ex vivo and in vivo validation

INTRODUCTION

This study aimed to investigate the efficacy of a small-gauge microwave ablation antenna (MWA) with an enhanced cooling system (ECS) for generating more spherical ablation zones.

METHODS

A comparison was made between two types of microwave ablation antennas, one with ECS and the other with a conventional cooling system (CCS). The finite element method was used to simulate in vivo ablation. Two types of antennas were used to create MWA zones for 5, 8, 10 min at 50, 60, and 80 W in ex vivo bovine livers (n = 6) and 5 min at 60 W in vivo porcine livers (n = 16). The overtreatment ratio, ablation aspect ratio, carbonization area, and other characteristcs of antennas were measured and compared using numerical simulation and gross pathologic examination.

RESULTS

In numerical simulation, the ECS antenna demonstrated a lower overtreatment ratio than the CCS antenna (1.38 vs 1.43 at 50 W 5 min, 1.19 vs 1.35 at 50 W 8 min, 1.13 vs 1.32 at 50 W 10 min, 1.28 vs 1.38 at 60 W 5 min, 1.14 vs 1.32 at 60 W 8 min, 1.10 vs 1.30 at 60 W 10 min). The experiments revealed that the ECS antenna generated ablation zones with a more significant aspect ratio (0.92 ± 0.03 vs 0.72 ± 0.01 at 50 W 5 min, 0.95 ± 0.02 vs 0.70 ± 0.01 at 50 W 8 min, 0.96 ± 0.01 vs 0.71 ± 0.04 at 50 W 10 min, 0.96 ± 0.01 vs 0.73 ± 0.02 at 60 W 5 min, 0.94 ± 0.03 vs 0.71 ± 0.03 at 60 W 8 min, 0.96 ± 0.02 vs 0.69 ± 0.04 at 60 W 10 min) and a smaller carbonization area (0.00 ± 0.00 cm2 vs 0.54 ± 0.06 cm2 at 50 W 5 min, 0.13 ± 0.03 cm2 vs 0.61 ± 0.09 cm2 at 50 W 8 min, 0.23 ± 0.05 cm2 vs 0.73 ± 0.05 m2 at 50 W 10 min, 0.00 ± 0.00 cm2 vs 1.59 ± 0.41 cm2 at 60 W 5 min, 0.23 ± 0.22 cm2 vs 2.11 ± 0.63 cm2 at 60 W 8 min, 0.57 ± 0.09 cm2 vs 2.55 ± 0.51 cm2 at 60 W 10 min). Intraoperative ultrasound images revealed a hypoechoic area instead of a hyperechoic area near the antenna. Hematoxylin-eosin staining of the dissected tissue revealed a correlation between the edge of the ablation zone and that of the hypoechoic area.

CONCLUSIONS

The ECS antenna can produce more spherical ablation zones with less charring and a clearer intraoperative ultrasound image of the ablation area than the CCS antenna.

Update on Percutaneous Ablation for Sarcoma

PURPOSE OF REVIEW

To provide an update on the current state of percutaneous thermal ablation in the treatment of sarcoma.

RECENT FINDINGS

Data continue to accrue in support of ablation for local control and palliation of specific sarcoma subtypes such as extra-abdominal desmoid fibromatosis and for broader indications such as the treatment of oligometastatic disease. The synergistic possibilities of various combination therapies such as cryoablation and immunotherapy represent intriguing areas of active investigation. Histotripsy is an emerging non-invasive, non-thermal ablative modality that may further expand the therapeutic arsenal for sarcoma treatment. Percutaneous thermal ablation is a valuable tool in the multidisciplinary management of sarcoma, offering a minimally invasive adjunct to surgery and radiation therapy. Although there remains a paucity of high-level evidence specific to sarcomas, ablation techniques are demonstrably safe and effective for achieving local tumor control and providing pain relief in select patients and are of particular benefit in those with metastatic disease or requiring palliative care.

Percutaneous Microwave Ablation for Treatment of Retroperitoneal Tumors

Purpose To determine if microwave ablation (MWA) of retroperitoneal tumors can safely provide high rates of local tumor control. Materials and Methods This retrospective study included 19 patients (median age, 65 years [range = 46-78 years]; 13 [68.4%] men and six [31.6%] women) with 29 retroperitoneal tumors treated over 22 MWA procedures. Hydrodissection (0.9% saline with 2% iohexol) was injected in 17 of 22 (77.3%) procedures to protect nontarget anatomy. The primary outcomes evaluated were local tumor progression (LTP) and complication rates. Oncologic outcomes, including overall survival (OS), progression-free survival (PFS), and treatment-free interval (TFI), were examined as secondary outcome measures. Results Median follow-up was 18 months (range = 0.5-113). Hydrodissection was successful in displacing nontarget anatomy in 16 of 17 (94.1%) procedures. The LTP rate was 3.4% (one of 29; 95% CI: 0.1, 17.8) per tumor and 5.3% (one of 19; 95% CI: 0.1, 26.0) per patient. The overall complication rate per patient was 15.8% (three of 19), including two minor complications and one major complication. The OS rate at 1, 2, and 3 years was 81.8%, 81.8%, and 72.7%, respectively, with a median OS estimated at greater than 7 years. There was no evidence of a difference in OS (P = .34) and PFS (P = .56) between patients with renal cell carcinoma (six of 19 [31.6%]) versus other tumors (13 of 19 [68.4%]) and patients treated with no evidence of disease (15 of 22 [68.2%]) versus patients with residual tumors (seven of 22 [31.8%]). Median TFI was 18 months (range = 0.5-108). Conclusion Treatment of retroperitoneal tumors with MWA combined with hydrodissection provided high rates of local control, prolonged systemic therapy-free intervals, and few serious complications. Keywords: Ablation Techniques (ie, Radiofrequency, Thermal, Chemical), Retroperitoneum, Microwave Ablation, Hydrodissection © RSNA, 2024.

CT-guided Percutaneous Microwave Ablation Combined with Local Radiotherapy or Chemotherapy of Malignant Pulmonary Tumors

BACKGROUND AND OBJECTIVE

The study aimed to investigate the clinical efficacy of CT-guided microwave ablation (MWA) combined with 125I seed implantation or bronchial arterial infusion (BAI) chemotherapy in the treatment of malignant pulmonary tumors.

METHODS

A total of 56 patients who underwent MWA, MWA combined with 125I particle implantation, or MWA combined with BAI chemotherapy for advanced lung cancer or metastatic lung cancer from January 2015 to June 2021 in Guangdong Provincial People's Hospital were enrolled. Among them, 21 patients were treated with MWA (MWA), 18 with MWA combined with 125I seed implantation (MWA+125I), and 17 with MWA combined with BAI chemotherapy (MWA+BAI). The short-term outcomes, complications, Eastern Cooperative Oncology Group (ECOG) performance score (Zubrod-ECOG-WHO, ZPS), survival, and factors related to survival were compared between the three groups.

RESULTS

The response rate of the MWA group (9.52%) was significantly lower than that of the MWA+125I group (50.00%) and MWA+BAI chemotherapy group (47.06%), and the differences were statistically significant (p < 0.05). The incidence of complications in the MWA, MWA+125I, and MWA+BAI chemotherapy groups was 47.62%, 55.56%, and 52.94%, respectively, with no significant difference (p > 0.05). Three months after the treatment, the ZPS of the MWA+125I and MWA+BAI chemotherapy groups was significantly lower than before treatment and significantly lower than that of the MWA group in the same period; the differences were statistically significant (p < 0.05). The median survival time of the MWA+125I group was 18 (9.983, 26.017) months and that of the MWA+BAI chemotherapy group was 21 (0.465, 41.535) months, both of which were higher than that of the MWA group [11 (6.686, 15.314) months]; the differences were statistically significant (p < 0.05). Cox regression analysis was performed on the factors related to survival and revealed treatment mode as a protective factor [HR = 0.433, 95% CI = (0.191, 0.984), p = 0.046]. Other factors, such as gender, age, and tumor size, did not independently affect survival.

CONCLUSION

CT-guided MWA combined with 125I seed implantation and MWA combined with BAI chemotherapy are safe and effective for the treatment of advanced lung cancer and metastatic lung cancer, and can control tumor progression and prolong survival time.

Iodine-125 seed implantation in the treatment of malignant tumors

Malignant tumors are major causes of morbidity and mortality in China. Despite advances in surgical, radiological, chemotherapeutic, molecular targeting, and immunotherapeutic treatments, patients with malignant tumors still have poor prognoses. Low-dose-rate brachytherapy, specifically 125I seed implantation, is beneficial because of its high local delivery dose and minimal damage to surrounding tissues. Consequently, it has gained increasing acceptance as a treatment modality for various malignant tumors. In this study, we explored the fundamental principles, clinical applications, and new technologies associated with 125I radioactive seed implantation.

LAG3 blockade coordinates with microwave ablation to promote CD8+ T cell-mediated anti-tumor immunity

Background

The immune checkpoint inhibitors (ICIs) combined with other therapeutic strategies have shown exciting results in various malignancies, and ICIs have now become the gold standard for current cancer treatment. In several preclinical and clinical investigations, ablation coupled with immunotherapy has proved to be quite effective. Our previous studies have shown that ablation coupled with ICI is a potential anti-cancer regimen for colorectal cancer liver metastases (CRLM). Furthermore, we have reported that following microwave ablation (MWA), the expression of LAG3 is up-regulated in tumor microenvironment (TME), indicating that LAG3 is implicated in the regulation of immunosuppressive immune response, and combination therapy of MWA and LAG3 blockade can serve as a promising therapeutic strategy against cancer.

Methods

The expression of LAG3 was investigated in this study utilizing a preclinical mouse model treated with MWA. Moreover, we monitored the tumor development and survival in mice to assess the anti-cancer effects of MWA alone or in combination with LAG3 blockade. Flow cytometry was also used to phenotype the tumor-infiltrating lymphocytes (TILs) and CD8⁺ T cell effector molecules. We finally analyzed the single-cell RNA sequencing (scRNA-seq) data of infiltrating CD45⁺ immune cells in the tumors from the MWA alone and MWA combined with LAG3 blockade groups.

Results

After MWA, the expression of LAG3 was up-regulated on sub-populations of TILs, and introducing LAG3 blockade to MWA postponed tumor development and extended survival in the MC38 tumor model. Flow cytometry and scRNA-seq revealed that LAG3 blockade in combination with MWA markedly boosted the proliferation and the function of CD8⁺ TILs, leading to altered myeloid cells in the TME.

Conclusion

Combination therapy of LAG3 blockade and MWA was a unique therapeutic regimen for some solid tumors, and such combination therapy might reprogram the TME to an anti-tumor manner.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03646-7.

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.

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.

Significance of 125I radioactive seed implantation on growth differentiation factor and programmed death receptor-1 during treatment of oral cancer

BACKGROUND

Oral cancer (OC) is the most common malignant tumor in the oral cavity, and is mainly seen in middle-aged and elderly men. At present, OC is mainly treated clinically by surgery or combined with radiotherapy and chemotherapy; but recently, more and more studies have shown that the stress trauma caused by surgery and the side effects of radiotherapy and chemotherapy seriously affect the prognosis of patients.

AIM

To determine the significance of ¹²⁵I radioactive seed implantation on growth differentiation factor 11 (GDF11) and programmed death receptor-1 (PD-1) during treatment of OC.

METHODS

A total of 184 OC patients admitted to The Second Affiliated Hospital of Jiamusi University from May 2015 to May 2017 were selected as the research subjects for prospective analysis. Of these patients, 89 who received ¹²⁵I radioactive seed implantation therapy were regarded as the research group (RG) and 95 patients who received surgical treatment were regarded as the control group (CG). The clinical efficacy, incidence of adverse reactions and changes in GDF11 and PD-1 before treatment (T0), 2 wk after treatment (T1), 4 wk after treatment (T2) and 6 wk after treatment (T3) were compared between the two groups.

RESULTS

The efficacy and recurrence rate in the RG were better than those in the CG (P < 0.05), while the incidence of adverse reactions and survival rate were not different. There was no difference in GDF11 and PD-1 between the two groups at T0 and T1, but these factors were lower in the RG than in the CG at T2 and T3 (P < 0.05). Using receiver operating characteristic (ROC) curve analysis, GDF11 and PD-1 had good predictive value for efficacy and recurrence (P < 0.001).

CONCLUSION

¹²⁵I radioactive seed implantation has clinical efficacy and can reduce the recurrence rate in patients with OC. This therapy has marked potential in clinical application. The detection of GDF11 and PD-1 in patients during treatment showed good predictive value for treatment efficacy and recurrence in OC patients, and may be potential targets for future OC treatment.

Effectiveness and safety of a robot-assisted 3D personalized template in 125I seed brachytherapy of thoracoabdominal tumors

PURPOSE

This research aims to evaluate the effectiveness and safety of a robot-assisted 3D personalized template in 125I seed brachytherapy of thoracoabdominal tumors.

MATERIAL AND METHODS

Forty-three patients with different tumors were involved in this research between 2013 and 2015. They were all eligible to 125I seed implantation based on robot-assisted 3D personalized template. Meanwhile, 51 patients with similar tumors, which were treated with a conventional coplanar template, were involved for comparison. Follow-up was carried out after the surgery to evaluate the therapeutic efficacy, including overall survival (OS) of the patient and local control (LC) of the tumor. Complications were also summarized to evaluate the safety. Besides, statistical analysis was achieved to investigate possible factors associated with the result.

RESULTS

In the robot-assisted 3D personalized template-guided brachytherapy, the median target volume treated by the prescription dose (V100) was 95.3% (range, 92.4-109.8), and the median dose administered to 90% of the target volume (D90) was 126.1 Gy (range, 114.2-132.0), improved 5% and 8% compared with the conventional template-guided brachytherapy, respectively. The median OS was 30 months (95% CI: 19.4-40.6) and the rates of 2-year OS and LC were 58.1% and 86.0%, respectively. The median OS was prolonged 10 months and the 2-year OS and LC were improved 18.9% and 23.3% compared with the conventional template-guided brachytherapy, respectively.

CONCLUSIONS

Through analysis of the selected patients with thoracoabdominal tumors, the robot-assisted 3D personalized template in 125I seed brachytherapy was a more effective and safer method. It can achieve a more favorable OS and LC.