Expert consensus on computed tomography-assisted three-dimensional-printed coplanar template guidance for interstitial permanent radioactive 125I seed implantation therapy

3D printing in palliative medicine: systematic review

BACKGROUND

Three-dimensional printing (3DP) enables the production of highly customised, cost-efficient devices in a relatively short time, which can be particularly valuable to clinicians treating patients with palliative care intent who are in need of timely and effective solutions in the management of their patients' specific needs, including the relief of distressing symptoms.

METHOD

Four online databases were searched for articles published by December 2020 that described studies using 3DP in palliative care. The fields of application, and the relevant clinical and technological data were extracted and analysed.

RESULTS

Thirty studies were reviewed, describing 36 medical devices, including anatomical models, endoluminal stents, navigation guides, obturators, epitheses, endoprostheses and others. Two-thirds of the studies were published after the year 2017. The main reason for using 3DP was the difficulty of producing customised devices with traditional methods. Eleven papers described proof-of-concept studies that did not involve human testing. For those devices that were tested on patients, favourable clinical outcomes were reported in general, and treatment with the use of 3DP was deemed superior to conventional clinical approaches. The most commonly employed 3DP technologies were fused filament fabrication with acrylonitrile butadiene styrene and stereolithography or material jetting with various types of photopolymer resin.

CONCLUSION

Recently, there has been a considerable increase in the application of 3DP to produce medical devices and bespoke solutions in the delivery of treatments with palliative care intent. 3DP was found successful in overcoming difficulties with conventional approaches and in treating medical conditions requiring highly customised solutions.

3D‑printed template‑guided iodine‑125 seed implantation to treat complete occlusion of the superior vena cava in pulmonary sarcomatoid carcinoma: A case report

Pulmonary sarcomatoid carcinoma (PSC), which is a type of non-small-cell lung carcinoma (NSCLC), is characterized by a high degree of malignancy, poor differentiation and a high incidence of pulmonary malignancy. In addition, PSC has a stronger invasive ability than other types of NSCLC and is not sensitive to radiation or chemotherapy. Furthermore, 90% of PSC cases exhibit vascular invasion; therefore, there is a risk of multiple metastases to the lung, bone, adrenal glands and brain, and consequently a poor prognosis, in the early stage. Targeted therapy and immunotherapy currently offer a new treatment direction; however, there have not been any significant advances in localized treatment in recent years. Thus, there is an urgent need for new localized treatment strategies. The present study describes the case of a 65-year-old man with recurrence of PSC after multi-line treatment with chemotherapy, radiotherapy, gamma knife and argon-helium knife treatment. In addition, the patient developed superior vena cava syndrome, and exhibited severe compression of the superior vena cava, chest discomfort, dyspnea and severe facial edema after chemotherapy, local gamma knife therapy (35 Gy, delivered through 14 2.5-Gy doses), argon-helium knife therapy and radiation therapy (28 Gy, delivered through seven 4-Gy doses). Partial remission was achieved after local implantation of iodine-125 (I125) seed under the guidance of a 3D-printed template, with progression-free survival observed up to 8 months afterwards. In conclusion, in patients with PSC who develop superior vena cava blockage after numerous treatment regimens, salvage I125 brachytherapy with a 3D-printed template may be suitable, and may improve local control and symptoms.

Brachytherapy for cervical cancer: from intracavitary to interstitial technique

Cervical cancer is a common malignant tumor of female reproductive system. Radiation therapy is one of the main methods of cervical cancer treatment, of which brachytherapy is an essential and important part of radiation therapy for locally advanced cervical cancer. With the rapid development of imaging technologies such as computed tomography (CT) and magnetic resonance imaging (MRI), brachytherapy for cervical cancer has gradually developed from traditional two-dimensional image-guided technology to three-dimensional image-guided technology. And there are more and more treatment methods, including intracavitary brachytherapy, interstitial brachytherapy, and intracavitary combined interstitial implantation brachytherapy. We performed a PubMed search for introduce the application progress of intracavity, implantation, intracavity combined implantation brachytherapy and radioactive seed implantation, and discuss the dosimetric feasibility of internal and external fusion irradiation.

Rhabdomyosarcoma: Current Therapy, Challenges, and Future Approaches to Treatment Strategies

Rhabdomyosarcoma is a rare cancer arising in skeletal muscle that typically impacts children and young adults. It is a worldwide challenge in child health as treatment outcomes for metastatic and recurrent disease still pose a major concern for both basic and clinical scientists. The treatment strategies for rhabdomyosarcoma include multi-agent chemotherapies after surgical resection with or without ionization radiotherapy. In this comprehensive review, we first provide a detailed clinical understanding of rhabdomyosarcoma including its classification and subtypes, diagnosis, and treatment strategies. Later, we focus on chemotherapy strategies for this childhood sarcoma and discuss the impact of three mechanisms that are involved in the chemotherapy response including apoptosis, macro-autophagy, and the unfolded protein response. Finally, we discuss in vivo mouse and zebrafish models and in vitro three-dimensional bioengineering models of rhabdomyosarcoma to screen future therapeutic approaches and promote muscle regeneration.

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.

Safety and efficacy of stereotactic ablative brachytherapy as a salvage therapy for recurrent chest wall cancer: A retrospective, multicenter study

Purpose

To evaluate the safety and efficacy of stereotactic ablative brachytherapy (SABT) as a salvage therapy for patients with recurrent chest wall cancer (rCWC) who have previously received external beam radiotherapy (EBRT) or surgery.

Materials and methods

Between November 2013 and October 2020, a total of 130 patients (including 75 men with a median age of 63 years) with rCWC treated with SABT were enrolled in this multicenter retrospective study. There were 97 cases of non-small-cell lung carcinoma, 24 cases of breast cancer, and 9 cases of thymic cancer. Of the patients included, 102 patients previously received surgery and 58 patients received EBRT, with systemic treatment progressing after recurrence. None of them were suitable or refused to undergo salvage EBRT or surgery again.

Results

During the 22 (4-70)-month median patient follow-up, 59 patients died. The local control (LC) rates at 6, 12, 24, and 36 months were 88.3%, 74.3%, 50.4%, and 36.7%, respectively. The 1-, 2- and 3-year survival rates were 85%, 56%, and 42%, respectively. The median overall survival was 26 months (95% CI, 18.9-33.1 months). The pain relief rate was 81%, and the median to remission time was 10 days. Univariate and multivariate analyses showed that independent prognostic factors for LC included tumor size and postoperative D90. On the other hand, independent prognostic factors for survival include the Karnofsky performance status (KPS) score, tumor size, and D90 19 patients (14.6%) developed grade I/II skin reaction complications. No grade III or severer complications occurred.

Conclusion

SABT is safe and effective as a salvage therapy for rCWC following EBRT/surgery. For patients with a KPS score greater than 80, prescribed dose greater than 130 Gy, and tumor size less than 4 cm may bring better results.

Efficacy and safety of CT-guided 125I seed implantation by coplanar template as a salvage therapy for vertebral metastases after failure of external beam radiation therapy: a retrospective study

Purpose

To evaluate the efficacy safety of computed tomography (CT)-guided ¹²⁵I seed implantation by coplanar template for vertebral metastases after failure of external beam radiation therapy (EBRT).

Material and methods

Retrospective analysis of the clinical outcomes of 58 patients with vertebral metastases after failure of EBRT, who underwent ¹²⁵I seed implantation as a salvage treatment with a CT-guided coplanar template-assisted technique from January 2015 to January 2017.

Results

The mean post-operative NRS score decreased significantly at T_4w (3.5 ± 0.9, p<0.01), T_8w (2.1 ± 0.9, p<0.01), T_12w (1.5 ± 0.7, p< 0.01) and T_6m (1.2 ± 0.6, p< 0.01) respectively. The local control rates after 3, 6, 9 and 12 months were 100% (58/58), 93.1% (54/58), 87.9% (51/58), and 81% (47/58), respectively. The median overall survival time was 18.52months (95% CI, 16.24-20.8), and 1- and 2-year survival rates were 81% (47/58) and 34.5% (20/58), respectively. By performing a paired t-test analysis, there was no significant difference in D90, V90, D100, V100, V150, V200, GTV volume, CI, EI and HI between preoperative and postoperative (p>0.05).

Conclusions

¹²⁵I seed implantation can be used as a salvage treatment for patients with vertebral metastases after failure of EBRT.

Multiple direction needle-path planning and inverse dose optimization for robotic low-dose rate brachytherapy

PURPOSE

Robotic systems to assist needle placements for low-dose rate brachytherapy enable conformal dose planning only restricted to path planning around risk structures. We report a treatment planning system (TPS) combining multiple direction needle-path planning with inverse dose optimization algorithms.

METHODS

We investigated in a path planning algorithm to efficiently locate needle injection points reaching the target volume without puncturing risk structures. A candidate needle domain with all combinations of trajectories is used for the optimization process. We report a modular algorithm for inverse radiation plan optimization. The initial plan with V100>99% is generated by the "greedy optimizer". The "remove-seed algorithm" reduces the number of seeds in the high dose regions. The "depth-optimizer" varies the insertion depth of the needles. The "coverage-optimizer" locates under-dosed areas in the target volume and supports them with an additional amount of seeds. The dose calculation algorithm is benchmarked on an image set of a phantom with a liver metastasis (prescription dose Dpr=100Gy) and is re-planned in a commercial CE-marked TPS to compare the calculated dose grids using a global gamma analysis. The inverse optimizer is benchmarked by calculating 10 plans on the same phantom to investigate the stability and statistical variability of the dose parameters.

RESULTS

The path planning algorithm efficiently removes 72.5% of all considered injection points. The candidate needle domain consists of combinations of 1971 tip points and 827 injection points. The global gamma analysis with gamma 1%=2.9Gy, 1mm showed a pass rate of 98.5%. The dose parameters were V100=99.1±0.3%, V150=76.4±2.5%, V200=44.5±5.5% and D90=125.9±3.6Gy and 10.7±1.3 needles with 34.0±0.8 seeds were used. The median of the TPS total running time was 4.4minutes.

CONCLUSIONS

The TPS generates treatment plans with acceptable dose coverage in a reasonable amount of time. The gamma analysis shows good accordance to the commercial TPS. The TPS allows taking full advantage of robotic navigation tools to enable a new precise and safe method of minimally invasive low-dose-rate brachytherapy.

I-125 seed-loaded versus normal stent insertion for obstructive esophageal cancer: a meta-analysis

Introduction

Malignant esophageal obstruction is usually caused by esophageal and other chest cancers. More than 80% of cases of obstructive esophageal cancer (OEC) have lost the chance of curative resection. Stent insertion is a first-line palliative approach used to treat incurable OEC.

Aim

To gauge the relative clinical efficacy of I-125 seed-loaded stent (ISS) versus normal stent (NS) insertion as a treatment for OEC.

Material and methods

Querying of the PubMed, Embase, and Cochrane Library databases was conducted to find all relevant studies published up to November 2020. The meta-analysis was undertaken using RevMan v5.3.

Results

We identified 158 studies initially, eight (4 randomized controlled trials and 4 retrospective studies) of which were used in this meta-analysis. We found that the two groups exhibited the comparable pooled Δdysphagia scores (MD = 0.02; p = 0.80), stent restenosis rates (OR = 0.97; p = 0.89), stent migration rates (OR = 0.81; p = 0.63), severe chest pain rates (OR = 1.05; p = 0.81), hemorrhage rates (OR = 1.53; p = 0.16), aspiration pneumonia rates (OR = 0.72; p = 0.38), and fistula formation rates (OR = 1.47; p = 0.44). The pooled time-to-restenosis and survival were both significantly longer in the ISS group (p = 0.04 and < 0.0001, respectively). Significant heterogeneity was detected in the endpoints of Δdysphagia scores and survival (I² = 73% and 86%, respectively). Funnel plot analysis indicated an absence of publication bias related to the selected study endpoints.

Conclusions

For patients with OEC, our meta-analysis indicated that ISS insertion could provide longer stent patency and survival than NS insertion.

Stereotactic Ablative Brachytherapy: Recent Advances in Optimization of Radiobiological Cancer Therapy

Brachytherapy (BT), a type of focal anti-cancer radiotherapy, delivers a highly focused radiation dose to localized tumors, sparing surrounding normal tissues. Recent technological advances have helped to increase the accuracy of BT and, thus, improve BT-based cancer treatment. Stereotactic ablative brachytherapy (SABT) was designed to improve the ablative effect of radiation, which was achieved via improved image guidance, and calculation of ablative dose, shorter treatment duration, and better organ preservation. Recently collected data characterized SABT as having the potential to cure various early-stage cancers. The method provides higher tumor control rate levels that were previously achievable only by surgical resection. Notably, SABT is suitable for application with unresectable malignancies. However, the pathological assessment of SABT irradiated tumors is limited due to difficulties in specimen acquisition. Prostate, lung, liver, and gynecological cancers are the most commonly reported SABT-treated malignancies. This study will give an overview of SABT, focusing on the advances in SABT optimization, and provide insights on the future benefits of the combined application of SABT with cancer immunotherapies.

The Accuracy of Individualized 3D-Printing Template-Assisted I125 Radioactive Seed Implantation for Recurrent/Metastatic Head and Neck Cancer

Purpose

To evaluate the accuracy of individualized 3D-printing template-assisted I¹²⁵ radioactive seed implantation (3D-PT assisted I¹²⁵ RSI) for recurrent/metastatic head and neck cancer.

Materials and Methods

From February 2017 to January 2020, clinical data of 41 patients (mean age, 58.5 ± 16.1 years; 28 males) with recurrent (48.8%)/metastatic (51.2%) head and neck cancer underwent individualized 3D-PT assisted I¹²⁵ RSI under CT guidance in a single institute were retrospectively reviewed. Total 430 seed needles [mean, 10.5 (range 3–17) per patient] were inserted.

Results

All seed needles were inserted manually in a single attempt with the technical success rate of 100% without major perioperative complications. The mean needle’s entrance deviation was 0.090 cm (95% Confidence Interval, 0.081–0.098). The mean intraoperative depth and angle of the needle were consistent with that of planned (6.23 ± 0.24 vs. 6.21 ± 0.24 cm, p = 0.903; 83.14 ± 3.64 vs. 83.09 ± 3.66 degrees, p = 0.985, respectively). The mean deviation between the needle’s planned and intraoperative depth and angle was 0.168 ± 0.024 cm and 1.56 ± 0.14 degrees, respectively. The postoperative dosimetry parameters, including D90, D100, V100, V150, V200, conformity index, external index, and homogeneity index, were all well-coordinated with planned dosimetry without significant difference (p = 0.515, 0.662, 0.958, 0.865, 0.872, 0.278, 0.456, and 0.989, respectively).

Conclusions

Within the limitation of this study, individualized 3D-PT assisted I¹²⁵ RSI may be accurate in obtaining favorable postoperative dosimetry for patients with recurrent/metastatic head and neck cancer.

Clinical Trial Registration

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Palliative local treatment of bone metastases by 125I seed brachytherapy under DynaCT guidance: single-center experience

PURPOSE

We aimed to evaluate the clinical benefit of 125I seed brachytherapy under DynaCT guidance for palliative local treatment of bone metastases.

METHODS

From December 2014 to September 2017, 82 patients with painful bone metastases, who experienced treatment failure using standard strategies or rejected treatment were enrolled in this retrospective study. All patients underwent 125I seed brachytherapy under DynaCT guidance. Technical success, visual analogue scale (VAS), numerical rating scale (NRS), verbal rating scale (VRS), Karnofsky performance status (KPS) and complications were analyzed.

RESULTS

The success rate of 125I seed implantation was 100%. The VAS and NRS scores for the most severe pain were 7.0 (5.0-9.0) and 8.0 (6.0-9.0) before brachytherapy. The pain scores assessed every 2 hours gradually decreased within 12 hours (p < 0.001). A comparison of KPS scores showed that patients had significantly better quality of life on weeks 1, 4, and 8 than on week 0 (p < 0.001). The associated complications were mild subcutaneous hemorrhage 25.6% (21/82), fever 7.3% (6/82), minor displacement of radioactive seeds 5.0% (4/82), pathologic fracture 2.4% (2/82), and local skin reaction 2.4% (2/82). After symptomatic treatment, all complications were relieved. Minor displacement of radioactive seeds did not cause damage to adjacent tissues. No serious life-threatening complications occurred in the study group.

CONCLUSION

DynaCT-guided 125I seed implantation is a safe and effective method for palliation of painful bone metastases from cancer after failure or rejection of conventional treatments.

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.