American Brachytherapy Society consensus guidelines for thoracic brachytherapy for lung cancer

Stereotactic ablative brachytherapy versus percutaneous microwave ablation for early-stage non-small cell lung cancer: a multicenter retrospective study

BACKGROUND

To analyze the efficacy of stereotactic ablative brachytherapy (SABT) and percutaneous microwave ablation (MWA) for the treatment of early-stage non-small cell lung cancer (NSCLC).

METHODS

Patients with early-stage (T1-T2aN0M0) NSCLC who underwent CT-guided SABT or MWA between October 2014 and March 2017 at four medical centers were retrospectively analyzed. Survival, treatment response, and procedure-related complications were assessed.

RESULTS

A total of 83 patients were included in this study. The median follow-up time was 55.2 months (range 7.2-76.8 months). The 1-, 3-, and 5-year overall survival (OS) rates were 96.4%, 82.3%, and 68.4% for the SABT group (n = 28), and 96.4%, 79.7%, and 63.2% for MWA group (n = 55), respectively. The 1-, 3-, and 5-year disease-free survival (DFS) rates were 92.9%, 74.6%, and 54.1% for SABT, and 92.7%, 70.5%, and 50.5% for MWA, respectively. There were no significant differences between SABT and MWA in terms of OS (p = 0.631) or DFS (p = 0.836). The recurrence rate was also similar between the two groups (p = 0.809). No procedure-related deaths occurred. Pneumothorax was the most common adverse event in the two groups, with no significant difference. No radiation pneumonia was found in the SABT group.

CONCLUSIONS

SABT provided similar efficacy to MWA for the treatment of stage I NSCLC. SABT may be a treatment option for unresectable early-stage NSCLC. However, future prospective randomized studies are required to verify these results.

Advanced navigation technology enables endobronchial brachytherapy for peripheral lung cancer: An old technique plays a new role

PURPOSE

To investigate the feasibility of super-selectively endobronchial brachytherapy in the treatment of peripheral lung cancer guided by advanced navigation technology.

METHODS AND MATERIALS

Six patients with peripheral lung tumors successfully underwent treatment with super-selectively endobronchial brachytherapy guided by advanced navigation technology following pathway planning and were subsequently followed up to assess survival and treatment-related toxicities.

RESULTS

The endobronchial applicators were successfully placed inside the tumors of all patients using advanced navigation techniques according to the pretreatment plan, and brachytherapy was delivered at curative doses after evaluation using radiotherapy planning software. None of the patients showed local progression of the treated lesions during the follow-up for a duration ranging from 11 months to 35 months, with a median follow-up time of 23 months. The patient with the longest follow-up, nearly 3 years, exhibited a stable condition. After undergoing endobronchial brachytherapy, patients predominantly experienced localized fibrosis as indicated. No significant alterations in cardiopulmonary function were detected during the follow-up, and no other adverse effects were found.

CONCLUSIONS

The use of endobronchial brachytherapy for the curative treatment of peripheral lung cancers is feasible. Furthermore, the development of novel bronchial navigation techniques has the potential to broaden the application of endobronchial brachytherapy.

A postimplant dosimetry simulation framework for robustness evaluation in permanent breast seed implant brachytherapy

BACKGROUND

Permanent breast seed implant (PBSI) brachytherapy is a promising treatment that has the potential to be widely utilized with increased standardization, optimization, and robustness. Excellent early efficacy and very high patient acceptance were reported, however, to further evaluate and improve planning strategies, a framework to quantify plan robustness to implant uncertainties is necessary.

PURPOSE

In this study, we aim to quantify clinical seed displacement using an automated algorithm and develop and validate a PBSI post-implant dosimetry simulation framework to evaluate PBSI plan robustness to implant uncertainties.

METHODS AND MATERIALS

Clinical PBSI seed displacements were quantified for 63 consecutive patients. A PBSI simulator was developed in Matlab (2020) by resampling clinical seed displacements and computing a range of possible post-implant dosimetry outcomes under various seed displacement scenarios. Simulations were performed retrospectively on 63 previous clinical plans to evaluate plan robustness to seed displacement.

RESULTS

Mean seed displacement for the whole cohort was 10 ± 6 mm. A clinical seed displacement database was established and a user interface was developed for the simulation framework. For all clinical plans, the median (range) value of simulated median ETV V90 in various seed displacement scenarios was 97.8% (87.5-100%).

CONCLUSIONS

A PBSI postimplant dosimetry simulation framework was developed and validated. Simulation results showed that the current PTV planning margin is sufficient to provide adequate postimplant dose coverage of ETV. This simulator can be used to evaluate plan robustness to seed displacement and will facilitate future research in improving PBSI planning methods.

Prognostic value of pretreatment FDG PET-CT for short-term efficacy of radioactive iodine-125 seed implantation in patients with NSCLC

PURPOSE

To analyze the short-term clinical response of radioactive iodine-125 seed implantation (I125-SI) in patients of non-small-cell lung cancer (NSCLC) and explore possible correlations of various metabolic parameters of pretreatment FDG PET-CT with the short-term efficacy of this treatment modality.

METHODS AND MATERIALS

The present study is a retrospective analysis of treatment records of 46 NSCLC patients who were treated with I125-SI for lung tumors in Tianjin First Central Hospital from January 2016 to December 2018. The correlation among parameters D90, gender, pathological pattern, age, maximum tumor diameter, Metabolic Tumor Volume (MTV), SUVmax, SUVpeak, SUVmean, Total Lesion Glycolysis (TLG), High metabolic tumor cell ratio (HMR) and Carcinoembryonic antigen(CEA)with short-term efficacy of I125-SI was analyzed by two independent-sample t-test, Mann-Whitney U test or Chi-squared test and binary logistic regression.

RESULTS

After uneventful completion of treatment, patients were followed up at regular intervals. At the first month followup, none of cases showed complete response (CR), while 4 cases showed partial response (PR). After 3 months, there were 2 cases of CR, and 25 cases of PR; after 6 months, there were 5 cases of CR, and 27 cases of PR. D90 (p= 0.028, OR:1.075, 95% CI:1.008-1.147), MTV (p= 0.026, OR: 0.918, 95% CI: 0.851-0.990), HMR (p= 0.020, OR: 0.003, 95% CI: 0-0.407) were independent predictors for the short-term efficacy. The predictive accuracy of MTV was medium (AUC = 0.781; cutoff value = 44.58). However, the predictive accuracies of D90 and HMR were low, with the values of AUC being 0.650 for both the parameters, and their cutoff values being 127.8 Gy and 0.27 respectively.

CONCLUSIONS

I125-SI is an effective therapy with few complications in NSCLC patients. Small MTV, high D90 and low HRM were found to be linked with better local control at 6 months postimplantation.

Effect of I-125 Seed Implantation on Lung Cancer and Its Environmental Impact

ABSTRACT

This paper compares the efficacy and adverse effects of iodine-125 ( 125 I) seed implantation and external beam radiotherapy (EBRT) in the treatment of lung cancer as well as impact of the 125 I radiation on the environment around the patients. A total of 40 patients who were admitted with lung cancer to our hospital from October 2017 to October 2018 were enrolled into this study. The patients were randomly assigned into study groups treated with 125 I seed implantation (20 patients) and a control group treated with EBRT (20 patients). The patients were followed up for 6 mo by CT scanning of the tumor size as well as measuring serum carcinoembryonic antigen (CEA), cytokeratin fragment (CYRA21-1), and neurospecific enolase (NSE) levels. The dose rate of 125 I at various distances and times after implantation was also measured. The local tumor control rate was higher in the study group than in the control group. CEA, NSE and CYFRA21-1 significantly decreased from the pre-treatment baseline in both groups (p < 0.05). Side effects of pneumothorax, hemoptysis, chest pain, and leukopenia occurred in the patients treated with 125 I seed implantation. Radiation of the 125 I isotope, which was correlated with the number of implanted 125 I seeds, decreased rapidly in a time- and distance-dependent manner. A lead apron could significantly block radiation of 125 I. Compared to EBRT, brachytherapy with 125 I seed implantation in the lung cancer had a better therapeutic outcome with fewer complications. A lead apron could protect members of patient's family as well as public from 125 I radiation.

High-dose-rate brachytherapy for airway malignancy a single institution experience

PURPOSE

To evaluate clinical outcomes of endobronchial malignancy treated using high-dose-rate endobronchial brachytherapy (HDREB).

METHODS AND MATERIALS

A retrospective chart review was conducted for all patients treated with HDREB for malignant airway disease between 2010 and 2019 at a single institution. Most patients had a prescription of 14 Gy in two fractions given a week apart. The Wilcoxon signed rank test and paired samples t test were used to compare changes in mMRC dyspnea scale prior to and after brachytherapy at first followup appointment. Toxicity data were collected for dyspnea, hemoptysis, dysphagia, and cough.

RESULTS

A total of 58 patients were identified. Most (84.5%) had primary lung cancer with advanced cancers, stage III or IV (86%). Eight were treated while admitted in the ICU. Previous external beam radiotherapy (EBRT) was received by 52%. An improvement in dyspnea was seen in 72%, with an mMRC dyspnoea scale score improvement of 1.13 points (p < 0.001). Most (22, 88%) had an improvement in hemoptysis and 18 out of 37 (48.6%) had an improvement in cough. Grade four to five events occurred in 8 (13%) at the median time of 2.5 months from brachytherapy. Twenty-two patients (38%) had complete obstruction of the airway treated. Median progression free survival was 6.5 months and median survival was 10 months.

CONCLUSIONS

We report a significant symptomatic benefit among patients receiving brachytherapy with endobronchial malignancy, with rates of treatment related toxicities similar to prior studies. Our study identified new subgroups of patients, ICU patients & those with complete obstruction, who benefited from HDREB.

Modern Tools for Modern Brachytherapy

This review aims to showcase the brachytherapy tools and technologies that have emerged during the last 10 years. Soft-tissue contrast using magnetic resonance and ultrasound imaging has seen enormous growth in use to plan all forms of brachytherapy. The era of image-guided brachytherapy has encouraged the development of advanced applicators and given rise to the growth of individualised 3D printing to achieve reproducible and predictable implants. These advances increase the quality of implants to better direct radiation to target volumes while sparing normal tissue. Applicator reconstruction has moved beyond manual digitising, to drag and drop of three-dimensional applicator models with embedded pre-defined source pathways, ready for auto-recognition and automation. The simplified TG-43 dose calculation formalism directly linked to reference air kerma rate of high-energy sources in the medium water remains clinically robust. Model-based dose calculation algorithms accounting for tissue heterogeneity and applicator material will advance the field of brachytherapy dosimetry to become more clinically accurate. Improved dose-optimising toolkits contribute to the real-time and adaptive planning portfolio that harmonises and expedites the entire image-guided brachytherapy process. Traditional planning strategies remain relevant to validate emerging technologies and should continue to be incorporated in practice, particularly for cervical cancer. Overall, technological developments need commissioning and validation to make the best use of the advanced features by understanding their strengths and limitations. Brachytherapy has become high-tech and modern by respecting tradition and remaining accessible to all.

High dose rate endoluminal brachytherapy in the treatment of endobronchial lesions - experience of a single institution and literature review

PURPOSE

To evaluate the efficacy and toxicity of Iridium-192 high-dose-rate endobronchial brachytherapy (HDR-EBT) for palliation of symptoms and for curative intent.

MATERIAL AND METHODS

This is a retrospective study of a prospectively registered cohort of 31 patients with endobronchial lesions treated with HDR-EBT at our institution between 2008 and 2020. Eighteen patients were treated with palliative intent and 13 curative intent; 4 of them as a boost to external radiation therapy (XRT). The primary objectives of the study were to analyze the symptomatic relief, endoscopic response, and treatment-related toxicity. As a secondary endpoint, survival analyses were performed.

RESULTS

In palliative setting, most of the symptomatic patients (80%) presented a significant clinical improvement and 75% presented endoscopic improvement of the lesions. In curative setting, all patients with visible lesions had endoscopic improvement and better survival than palliatively treated patients (median: 78 and 9 months, respectively; p = 0.002). There were no complications in 91.4% of the treatments: only one pneumonia, one pneumothorax and one bronchial stenosis occurred, all in palliative treatments. No fatal hemoptysis happened. Acute toxicity was mild (G ≤ 2) and transitory.

DISCUSSION

HDR-EBT is an excellent, safe, and inexpensive palliative treatment of symptoms caused by endobronchial growth of tumors in the proximal airway, either as a single treatment or in combination with XRT. It can also be an alternative in the treatment of initial malignant tumors when surgery or XRT is not possible, and it may also play a role in treating non-malignant bronchial obstructions.

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.

Therapeutic and prophylactic effects of radiation therapy in the management of recurrent granulation tissue induced tracheal stenosis: a review on the role of Endobronchial brachytherapy and external beam radiation therapy

PURPOSE

Granulation tissue-induced tracheal stenosis (mainly secondary to intubation or lung transplantation) is one of the most common etiologies of benign airway obstructions. Recurrence rates after standard treatment options (surgical resection and/or endobronchial interventions) can inadvertently worsen the stricture through the stimulation of more granulation tissue generation (via increased fibroblast activity and roliferation). Low-dose radiotherapy could be a promising tool to prevent granulation tissue formation after surgery and/or endobronchial interventions regarding its established role in the treatment of keloids or hypertrophic scars, two benign diseases with similar a pathophysiology to tracheal stenosis. This study reviews case reports and small series that used endobronchial brachytherapy (EBBT) or external beam radiotherapy (EBRT) for the management of refractory granulation tissue-induced tracheal stenosis after surgery and/or endobronchial interventions.

METHODS AND MATERIALS

Case reports and series (published up to October 2022) that reported outcomes of patients with recurrent granulation tissue-induced tracheal stenosis (after surgery and/or endobronchial interventions) treated by EBBT or EBRT (in definitive or prophylactic settings) were eligible.

RESULTS

Sixteen studies (EBBT: nine studies including 69 patients, EBRT: seven studies including 32 patients) were reviewed. The pooled success rate across all studies was 74% and 97% for EBBT and EBRT, respectively.

CONCLUSIONS

Radiation therapy appears to be effective in the management of selected patients with recurrent/refractory tracheal stenosis. Response to this treatment is usually good, but further studies with a larger number of patients and long-term followup are necessary to determine the optimal technique, dose, and timing of radiation therapy, late complications, the durability of response, and criteria for patient selection.

CT-guided Radioactive 125I Seed Implantation for Abdominal Incision Metastases of Colorectal Cancer: Safety and Efficacy in 17 Patients

INTRODUCTION

To retrospectively evaluate the safety and efficacy of computed tomography (CT)-guided iodine-125 (¹²⁵I) seed implantation for patients with abdominal incision metastases from colorectal cancer.

MATERIALS AND METHODS

Data of patients with abdominal incision metastases of colorectal cancer from November 2010 to October 2020 were retrospectively reviewed. Each incisional metastasis was percutaneously treated with ¹²⁵I seed implantation under CT guidance. Follow-up contrast-enhanced CT was reviewed, and the outcomes were evaluated in terms of objective response rate, complications, and overall survival.

RESULTS

A total of 17 patients were enrolled in this study. The median follow-up was 18 months (range, 2.7-22.1 months). At 3, 6, 12, and 18 months after the treatment, objective response rate was 52.9%, 63.6%, 33.3%, and 0%, respectively. A small amount of local hematoma occurred in two patients and resolved spontaneously without any treatment. Two patients experienced a minor displacement of radioactive seeds with no related symptoms. Severe complications, such as massive bleeding and radiation injury, were not observed. No ≥ grade 3 adverse events were identified. By the end of follow-up, 14 patients died of multiple hematogenous metastases. The one-year overall survival rate was 41.6%, and the median overall survival was 8.6 months.

CONCLUSION

CT-guided ¹²⁵I seed implantation brachytherapy is safe and feasible for patients with abdominal incision metastases from colorectal cancer.

BRACHY: A Randomized Trial to Evaluate Symptom Improvement in Advanced Non-Small Cell Lung Cancer Treated With External Beam Radiation With or Without High-Dose-Rate Intraluminal Brachytherapy

PURPOSE

Uncontrolled studies suggest that the addition of high-dose-rate intraluminal brachytherapy (HDRIB) to external beam radiation therapy (EBRT) may improve palliation for patients with advanced non-small cell lung cancer (NSCLC). The purpose of this study was to evaluate the potential clinical benefit of adding HDRIB to EBRT in a multicenter randomized trial.

METHODS AND MATERIALS

Patients with symptomatic stage III or IV NSCLC with endobronchial disease were randomized to EBRT (20 Gy in 5 daily fractions over 1 week or 30 Gy in 10 daily fractions over 2 weeks) or the same EBRT plus HDRIB (14 Gy in 2 fractions separated by 1 week). The primary outcome was the proportion of patients who achieved symptomatic improvement in patient-reported overall lung cancer symptoms on the Lung Cancer Symptom Scale (LCSS) at 6 weeks after randomization. Secondary outcomes included improvement in individual symptoms, symptom-progression-free survival, overall survival, and toxicity. The planned sample size was 250 patients based on detection of symptomatic improvement from 40% to 60% with a 2-sided α of .05 and 80% power.

RESULTS

A total of 134 patients were randomized over 4.5 years: 67 to each arm. The study closed early owing to slow accrual. The mean age was 69.8 years, and 67% of patients had metastatic disease. At 6 weeks, 19 patients (28.4%) in the EBRT arm and 20 patients (29.9%) in the EBRT plus HDRIB arm experienced an improvement in lung cancer symptoms (P = .84). When limited to patients who completed the LCSS, percentages were 40.4% versus 47.6%, respectively (P = .49). Between group differences in mean change scores (0.3-0.5 standard deviations) in favor of EBRT plus HDRIB were observed for overall symptoms, but only hemoptysis was significantly improved (P = .03). No significant differences were observed in progression-free or overall survival. Grade 3/4 toxicities were similar between groups.

CONCLUSIONS

Small to moderate improvements were seen in symptom relief with the combined therapy, but they did not reach statistical significance. Further research is necessary before recommending HDRIB in addition to EBRT for palliation of lung cancer symptoms.

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.

Clinical Outcome of CT-Guided Stereotactic Ablative Brachytherapy for Unresectable Early Non-Small Cell Lung Cancer: A Retrospective, Multicenter Study

Objective

To analyze the efficacy and safety of low dose rate stereotactic ablative brachytherapy (L-SABT) for treatment of unresectable early-stage non-small cell lung cancer (NSCLC).

Methods

Data of patients with early-stage NSCLC who received CT-guided L-SABT (radioactive I-125 seeds implantation) at eight different centers from December 2010 to August 2020 were retrospectively analyzed. Treatment efficacy and complications were evaluated.

Results

A total of 99 patients were included in this study. Median follow-up duration was 46.3 months (6.1-119.3 months). The 1-year, 3-year, and 5-year local control rates were 89.1%, 77.5%, and 75.7%, respectively. The 1-year, 3-year, and 5-year overall survival rates were 96.7%, 70.1%, and 54.4%, respectively. Treatment failure occurred in 38.4% of patients. Local/regional recurrence, distant metastasis, and recurrence combined with metastasis accounted for 15.1%, 12.1%, and 11.1%, respectively. Pneumothorax occurred in 47 patients (47.5%) with 19 cases (19.2%) needing closed drainage. The only radiation-related adverse reaction was two cases of grade 2 radiation pneumonia. KPS 80-100, T1, the lesion was located in the left lobe, GTV D90 ≥150 Gy and the distance between the lesion and chest wall was < 1 cm, were associated with better local control (all P < 0.05); on multivariate analysis KPS, GTV D90, and the distance between the lesion and chest wall were independent prognostic factors for local control (all P < 0.05). KPS 80-100, T1, GTV D90 ≥150 Gy, and the distance between the lesion and chest wall was < 1 cm were also associated with better survival (all P < 0.05); on multivariate analysis KPS, T stage, and GTV D90 were independent prognostic factors for survival (all P < 0.05). The incidence of pneumothorax in patients with lesions <1 cm and ≥1cm from the chest wall was 33.3% and 56.7%, respectively, and the differences were statistically significant (P = 0.026).

Conclusion

L-SABT showed acceptable efficacy in the treatment of unresectable early-stage NSCLC. But the incidence of pneumothorax is high. For patients with T1 stage and lesions <1 cm from the chest wall, it may have better efficacy. Prescription dose greater than 150 Gy may bring better results.

Overview of Interventional Pulmonology for Radiologists

Interventional pulmonology is a growing field specializing in minimally invasive procedures of the mediastinum, lungs, airways, and pleura. These procedures have both diagnostic and therapeutic indications and are performed for benign and malignant diseases. Endobronchial US has been combined with transbronchial needle aspiration to extend tissue sampling beyond the airways and into the lungs and mediastinum. Recent innovations extending the peripheral access of bronchoscopy include electromagnetic navigational bronchoscopy and thinner bronchoscopes. An important indication for therapeutic bronchoscopy is the relief of central airway obstruction, which may be severe and life threatening. Techniques for restoring patency of the central airways include mechanical debulking and multiple modalities for ablation, stent placement, and balloon bronchoplasty. Bronchoscopic lung volume reduction improves quality of life in certain patients with severe emphysema and is an important less invasive alternative to lung volume reduction surgery. Bronchial thermoplasty is likewise a nonpharmacologic treatment in patients with severe uncontrolled asthma. Many of these procedures have unique selection criteria that require precise evaluations at preprocedure imaging. Postprocedure imaging is also essential in determining outcome success and the presence of complications. Radiologists should be familiar with these procedures as well as the relevant imaging features in both planning and later surveillance. Evolving techniques that may become more widely available in the near future include robotic-assisted bronchoscopy, bronchoscopic transparenchymal nodule access, transbronchial cryobiopsy, ablation of early-stage cancers, and endobronchial intratumoral chemotherapy. An invited commentary by Wayne et al is available online. ^©RSNA, 2021.

Aortoesophageal fistula involving the central aortic arch salvaged with emergent percutaneous TEVAR, great vessel coverage and in vivo graft fenestration

Immediate intervention is needed for aortoesophageal fistulas (AEF), a rare but highly lethal cause of massive gastrointestinal hemorrhage. Emergent thoracic endovascular aortic repair (TEVAR) is considered first-line treatment for massive bleeding from AEFs. We describe an unusual and challenging case of TEVAR coverage of an AEF involving the central aortic arch immediately followed by in vivo endograft fenestration to regain arch vessel perfusion. In vivo fenestration, currently a procedure for emergency or investigational purposes only, was shown to be life saving in our case. The main complications associated with the procedure included stroke and infection, requiring esophagectomy and cervical diversion as well as ongoing antibiotic treatment.

Recommendations for intraoperative mesh brachytherapy: Report of AAPM Task Group No. 222

Mesh brachytherapy is a special type of a permanent brachytherapy implant: it uses low-energy radioactive seeds in an absorbable mesh that is sutured onto the tumor bed immediately after a surgical resection. This treatment offers low additional risk to the patient as the implant procedure is carried out as part of the tumor resection surgery. Mesh brachytherapy utilizes identification of the tumor bed through direct visual evaluation during surgery or medical imaging following surgery through radiographic imaging of radio-opaque markers within the sources located on the tumor bed. Thus, mesh brachytherapy is customizable for individual patients. Mesh brachytherapy is an intraoperative procedure involving mesh implantation and potentially real-time treatment planning while the patient is under general anesthesia. The procedure is multidisciplinary and requires the complex coordination of multiple medical specialties. The preimplant dosimetry calculation can be performed days beforehand or expediently in the operating room with the use of lookup tables. In this report, the guidelines of American Association of Physicists in Medicine (AAPM) are presented on the physics aspects of mesh brachytherapy. It describes the selection of radioactive sources, design and preparation of the mesh, preimplant treatment planning using a Task Group (TG) 43-based lookup table, and postimplant dosimetric evaluation using the TG-43 formalism or advanced algorithms. It introduces quality metrics for the mesh implant and presents an example of a risk analysis based on the AAPM TG-100 report. Recommendations include that the preimplant treatment plan be based upon the TG-43 dose calculation formalism with the point source approximation, and the postimplant dosimetric evaluation be performed by using either the TG-43 approach, or preferably the newer model-based algorithms (viz., TG-186 report) if available to account for effects of material heterogeneities. To comply with the written directive and regulations governing the medical use of radionuclides, this report recommends that the prescription and written directive be based upon the implanted source strength, not target-volume dose coverage. The dose delivered by mesh implants can vary and depends upon multiple factors, such as postsurgery recovery and distortions in the implant shape over time. For the sake of consistency necessary for outcome analysis, prescriptions based on the lookup table (with selection of the intended dose, depth, and treatment area) are recommended, but the use of more advanced techniques that can account for real situations, such as material heterogeneities, implant geometric perturbations, and changes in source orientations, is encouraged in the dosimetric evaluation. The clinical workflow, logistics, and precautions are also presented.

Palliative treatment with high-dose-rate endobronchial interventional radiotherapy (Brachytherapy) for lung cancer patients

PURPOSE

to report on the use of high-dose-rate (HDR) endobronchial interventional radiotherapy (brachytherapy, EBIRT) for palliation of symptoms in patients with lung cancer.

PATIENTS AND METHODS

retrospective review of lung cancer patients treated with HDR-EBIRT at our institution (1995-2017). Treatment results and treatment related toxicity were recorded. Clinical response was subjectively evaluated within 3 months after treatment. Overall survival (OS) was analyzed.

RESULTS

347 patients were identified. The median age was 69 years and the median follow-up time was 13.4 months. Most patients received external beam radiation therapy during the primary treatment. Within 3 months, 87.7% of the patients had complete or major response of their presenting symptoms. OS was 55.2% at 1 year, 18.3% at 2 years. Patients who had complete or major response had a longer median survival than other patients (13 versus 7 months, p = 0.03). Chronic bronchitis was found in 26.8%, while 7.8% of the patients died due to uncontrollable hemoptysis.

CONCLUSION

HDR-EBIRT is a safe and effective treatment option for the palliative treatment of lung cancer patients. HDR-EBIRT is most suitable as a re-irradiation technique. Further clinical studies are needed to validate its role.

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.

Efficacy and Safety Aiming at the Combined-Modality Therapy of External Beam Radiotherapy (40Gy) and Iodine-125 Seed Implantation for Locally Advanced NSCLC in the Elderly

Purpose

To evaluate the efficacy and safety of combined-modality therapy for elderly patients with locally advanced non-small-cell lung cancer (NSCLC) invading the chest wall.

Patients and Methods

We retrospectively enrolled 21 elderly patients (aged ≥60 years) with locally advanced NSCLC invading the chest wall. For external beam radiotherapy (EBRT) of the primary tumor, 40Gy was applied and supplemented with iodine-125 seed implantation while 60Gy was applied to the lymph nodes of the mediastinum. Follow-up was conducted every 3 months postoperatively. The related analytic parameters were change in tumor size, the objective response rate (ORR), the disease control rate (DCR), the degree of pain relief, the improvement of physical status, and toxicity.

Results

The combined-modality therapy significantly inhibited local growth of the tumor (from 7.84±1.20 to 4.69±1.90 cm) (P <0.0001), with 71.4% ORR and 90.5% DCR at 1 year. The cancer-related pain was significantly relieved (P <0.05) and physical status was significantly improved (P <0.05). No procedure-associated death or grade > 2 irradiation-related adverse effects were reported in this study.

Conclusion

The combined-modality therapy of EBRT with 40Gy and permanent iodine-125 seed implantation is an efficacious and safe treatment option for elderly patients with locally advanced NSCLC invading the chest wall.

Alternative methods for local ablation-interventional pulmonology: a narrative review

OBJECTIVE

To discuss and summarise the background and recent advances in the approach to bronchoscopic ablative therapies for lung cancer, focusing on focal parenchymal lesions.

BACKGROUND

This series focusses on the challenges highlighted by increasing recognition of the prognostically more favourable oligometastatic disease rather than the more frequent, but prognostically poor, high tumour burden metastatic disease. While surgery, stereotactic body radiation therapy (SBRT), and trans-thoracic percutaneous ablative techniques such as microwave (MWA) and radiofrequency ablation (RFA) are well recognised options for selected cases of pulmonary oligometastasis, bronchoscopic approaches to pulmonary tumour ablation are becoming realistic alternatives. An underlying tenet driving research and implementation in this domain is that percutaneous ablative techniques are obliged to traverse the pleura leading to a high rate of pneumothorax, and risks also goes up for peri-vascular lesions. Historically low yield bronchoscopic targeting of isolated peripheral tumors have significantly improved by incorporating multi-modality high resolution imaging and processing, including navigation planning and real-time image guidances (ultrasound, electromagnetic navigation, cone-beam CT). Combining advanced image guidance with ablative technology adaptations for bronchoscopic delivery opens up the options for high dose local ablative therapies that may reduce transthoracic complications and provide palliative to curative options for limited stage primary and oligometastatic diseases.

METHODS

We conduct a narrative review of the literature summarizing the history of bronchoscopic tumor ablation approaches, technical details including biologic rational for their uses, and current evidence for each modality, as well as investigations into future applications. Because of the relative paucity of prospective studies, we have been very inclusive in our inclusion of experiences from the published clinical databases.

CONCLUSIONS

Whilst surgical resection and SBRT remain the current mainstay of curative therapies for peripheral cancers, in the foreseeable future, developments and further research will see bronchoscopic ablative therapies become viable lung sparing alternatives in those deemed suitable. The future is bright.

Dosimetry investigation of a prototype of 169Yb seed brachytherapy for use in circular stapler

This study aims to investigate dosimetry parameters for the new design of ¹⁶⁹Yb seed in the form of a surgical staple for circular staplers commonly used in the abdominal incision and the esophageal and gastric surgery, which facilitates the precise placement. This seed includes a titanium tube with the inner diameter and outer diameter 0.68 mm and 2.2 mm, respectively, and length of 0.8 mm. Both sides of the tube are closed by titanium wires with the thickness of 0.65 mm by the laser. Natural ytterbium oxide is used after the thermal neutron activation; it is necessary for cooling time of 40 days. The dosimetry parameters were calculated based on the TG-43U1 using Monte Carlo MCNP5 code. The experimental dosimetry was performed by EBT3 radiochromic film to determine 2D dosimetry at near distance of the source and validate the MC code. The dose rate constant of MC calculation was obtained at 1.39cGyh^-1U^-1 ± 4% with the difference of 5% compared to another study. The dose distribution was symmetrical along the Z-axis and Y-axis (around the seed) and there was a uniform activity inside the tube. The distinction of dose rate was not noticeable at the 90 and 270 degrees on the Z-axis, which indicated a slight effect on staple legs in the matter of delivery dose. However, to understand dose distribution and introduce this source in a pre-clinical study, 3D dosimetry as well as further studying the heterogeneous function is required.

Automatic needle detection using improved random sample consensus in CT image-guided lung interstitial brachytherapy

Purpose

To develop a method for automatically detecting needles from CT images, which can be used in image‐guided lung interstitial brachytherapy to assist needle placement assessment and dose distribution optimization.

Material and Methods

Based on the preview model parameters evaluation, local optimization combining local random sample consensus, and principal component analysis, the needle shaft was detected quickly, accurately, and robustly through the modified random sample consensus algorithm. By tracing intensities along the axis, the needle tip was determined. Furthermore, multineedles in a single slice were segmented at once using successive inliers deletion.

Results

The simulation data show that the segmentation efficiency is much higher than the original random sample consensus and yet maintains a stable submillimeter accuracy. Experiments with physical phantom demonstrate that the segmentation accuracy of described algorithm depends on the needle insertion depth into the CT image. Application to permanent lung brachytherapy image is also validated, where manual segmentation is the counterparts of the estimated needle shape.

Conclusions

From the results, the mean errors in determining needle orientation and endpoint are regulated within 2° and 1 mm, respectively. The average segmentation time is 0.238 s per needle.

A dosimetric and centeredness comparison of the conventional and novel endobronchial applicators: A preliminary study

PURPOSE

This study compared the applicator position relative to the tracheal wall and dosimetric parameters between conventional and novel applicators among patients receiving endobronchial brachytherapy (EBBT) for intratracheal tumors.

METHODS AND MATERIALS

Data from 7 patients who received EBBT for intratracheal tumors were retrospectively analyzed; 4 and 3 patients were treated with conventional (2-wing) or novel (5-wing) applicators, respectively. Applicator centrality was evaluated using the distance between the center of the trachea and main bronchus (TMB) lumen and path of source (L). Dosimetric parameters, including plans normalized to D_2cc of the TMB = 45 Gy (normalized plan), were compared between the applicators.

RESULTS

The mean and maximum values of L in cases of the 2-wing applicator group were approximately 5.0 mm and 10.0 mm, respectively. In the novel applicator group, the corresponding values were approximately 3.0 and 6.0 mm, respectively. In the normalized plan of the 2-wing applicator group, the ranges of median V_90% of clinical target volume (CTV) and D_0.1cc of the TMB in all cases were 23.0-91.9% and 66.3-153.1 Gy, respectively. In the 5-wing applicator group, the corresponding values were 69.2-83.8% and 60.4-84.5 Gy, respectively.

CONCLUSIONS

In the 5-wing applicator group, the range was narrow in all dose-volume parameters except for D_2cc of the TMB. Compared to the conventional applicator, the 5-wing applicator can give a stable dose to the CTV and can reduce the maximum dose of the TMB. This suggests that stable EBBT can be given to any patient using the 5-wing applicator.

CT-guided 125I brachytherapy combined with chemotherapy for the treatment of unresectable or locally advanced pancreatic carcinoma

PURPOSE

We aimed to explore the feasibility and clinical effectiveness of percutaneous CT-guided iodine-125 (¹²⁵I) brachytherapy combined with chemotherapy for the treatment of patients with unresectable or locally advanced pancreatic carcinoma (PC).

METHODS

We retrospectively reviewed 66 patients with Stage III and IV PC who had received chemotherapy. A total of 35 (53%) patients receiving 125I brachytherapy and chemotherapy (gemcitabine + cisplatin, GP) were classified as Group A, and 31 (47%) patients who received GP chemotherapy alone were categorized as Group B. The evaluated indications were local control rate (LCR), local progression-free survival (LPFS), overall survival (OS), treatment-related complications, and the degree of symptom relief. Kaplan-Meier curves, log-rank test and Cox regression models were generated and used for further analysis to identify predictors of outcomes.

RESULTS

The median follow-up time was 6.00±0.84 months. The 1-, 3-, 6-, 12- and 18-month LCRs for Group A were 100% (35/35), 89.3% (25/28), 71.4% (15/21), 37.5% (3/8) and 33.3% (1/3), respectively; and those for Group B were 87.1% (27/31), 69.6% (16/23), 41.2% (7/17), 14.3% (1/7) and 0% (0/3), respectively. The LCR differed at 1-, 3- and 6-months (P = 0.032; P = 0.009; P = 0.030; respectively). The median LPFS was 7.00±0.30 months and 5.00±0.75 months for Groups A and B (P = 0.023), respectively; however, the median OS of the groups were not significantly different (8.00±0.77 months vs. 6.00±1.04 months. P = 0.917). No life-threatening complications occurred during or after the procedures. Patients in Group A experienced better pain control and relief of abdominal distension than those in Group B.

CONCLUSION

CT-guided 125I brachytherapy is a feasible, safe, and valuable treatment for patients with unresectable PC.

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.

Bronchoscopic treatment of inoperable nonsmall cell lung cancer

Patients with unresectable lung cancer range from those with early-stage or pre-invasive disease with comorbidities that preclude surgery to those with advanced stage disease in whom surgery is contraindicated. In such cases, a multidisciplinary approach to treatment is warranted, and may involve medical specialties including medical oncology, radiation oncology and interventional pulmonology. In this article we review bronchoscopic approaches to surgically unresectable lung cancer, including photodynamic therapy, brachytherapy, endoscopic ablation techniques and airway stenting. Current and past literature is reviewed to provide an overview of the topic, including a highlight of potential emerging approaches.

Development of an HDR-BT QA tool for source position verification

PURPOSE

This study aimed to develop a high-dose-rate brachytherapy (HDR-BT) quality assurance (QA) tool for verification of source positions, and to report on its effectiveness.

METHODS

We fabricated a cuboid phantom measuring 30 × 30×3 cm³ with spaces to embed Fletcher-Williamson tandem and ovoid applicators. Lead-based, cylindrically shaped radiopaque markers, which scatter radiation and blacken the Gafchromic^® RTQA2 films placed on the applicators, were inserted into the phantom to determine the applicator tip and reference source positions. A three-dimensional image-guided brachytherapy (3D-IGBT) plan was generated, and the source positions on the film and radiation treatment planning system (RTPS) were verified with the tool. Source position errors were evaluated as the distance in the applicator axis direction between the source position and the center position of two radiopaque marker pairs.

RESULTS

Source position errors on the film and RTPS were in good agreement with one another and were all within 0.5 mm for all applicators. Offset values of each applicator were in good agreement with the value determined in treatment planning (6 mm). The expanded measurement uncertainty of our QA tool was estimated to be 0.87 mm, with a coverage factor k of 2.

CONCLUSIONS

Our new HDR-BT QA tool developed for comprehensive source position verification will be useful for cross checking actual source positions and planned source positions on the RTPS.

125I Seed Brachytherapy Combined with Single-Agent Chemotherapy in the Treatment of Non-Small-Cell Lung Cancer in the Elderly: A Valuable Solution

Purpose

The aim of this study was to compare the effectiveness and safety of CT-guided ¹²⁵I seed brachytherapy combined with single-agent chemotherapy versus combined chemotherapy in the treatment of elderly NSCLC.

Materials and Methods

We retrospectively analyzed 110 patients (64 men and 46 women; mean age=71.25±7.14 years) who were diagnosed with NSCLC without distant metastases between January 2015 and May 2020. A total of 50 patients received ¹²⁵I brachytherapy combined with single-agent chemotherapy (group A), whereas 60 patients received combined chemotherapy (group B). The response to therapy and adverse effect were compared between groups. The local response rate was evaluated by CT. Progression-free survival (PFS) and overall survival (OS) data were obtained through clinical follow-up.

Results

All patients had been treated and were followed-up for 3-60 months. The median OS and PFS were 23.71±1.41 months (95% CI=20.95-26.47) vs 16.12±0.93 months (95% CI=14.31-17.93) (P<0.05) and 15.08±0.85 months (95% CI=13.42-16.74) vs 10.03±0.53 months (95% CI=9.01-11.06) (P<0.05) in group A and group B, respectively. The local response rate and clinical symptoms of patients in group A were significantly relieved when compared with group B. Severe complications were not observed in either group.

Conclusion

CT-guided ¹²⁵I seed brachytherapy combined with single-agent chemotherapy is an effective and safe therapy and shows promising results compared to combined chemotherapy alone for NSCLC in the elderly. A randomized study will be needed to assess the superiority of this combined modality treatment.

Brachytherapy vs external beam therapy among NSCLC patients undergoing limited surgical resection

PURPOSE

To compare brachytherapy to external beam radiation therapy (EBRT) with respect to overall survival (OS) and disease-specific survival (DSS) among NSCLC patients undergoing limited surgical resection.

METHODS

All cases of T1-4 N0 M0 NSCLC undergoing limited resection and either brachytherapy or EBRT diagnosed between 2004 and 2014 were extracted from the Surveillance, Epidemiology, and End Results database. Chi-square test and Fisher's exact analysis were used to analyze categorical variables while Student's t-test was used to analyze continuous variables. Univariate analysis to assess for differences in survival with respect to covariates was performed with the log-rank test. Multivariable analysis was performed with Cox proportional hazards regression models among the entire cohort and after sub-stratification by T stage.

RESULTS

Among 543 patients, 471 underwent EBRT and 72 underwent brachytherapy. Brachytherapy demonstrated improved OS and DSS on univariate analysis as compared to EBRT (p < 0.05). Cox regression also demonstrated improved OS and DSS with brachytherapy (HR 0.604; 95% CI [0.380; 0.961] and HR 0.524; 95% CI [0.303; 0.908], respectively). Sub-cohort analysis demonstrated significant improvement in survival only among patients with T1 disease with similar survival between brachytherapy and EBRT among higher stage disease.

CONCLUSIONS

Patients undergoing brachytherapy for T1-T4, N0, M0 NSCLC demonstrated at least similar survival as compared to those undergoing EBRT among patients undergoing limited resection. Improved survival was demonstrated among patients with T1 disease.

Safety and efficacy of apatinib combined with iodine-125 in chemotherapy-refractory advanced lung cancer: A case report

INTRODUCTION

Apatinib is a novel anti-angiogenic agent that targets vascular endothelial growth factor receptor-2, and is effective in patients with advanced lung cancer who are refractory to first-line chemotherapy. However, there are limited reports on concurrent apatinib therapy with iodine-125 radioactive seeds brachytherapy in elderly patients with advanced lung cancer.

PATIENT CONCERNS

We describe the first reported case of a 70-year-old woman with advanced lung cancer (T3N3M1, stage IV) who received concurrent apatinib and iodine-125 radioactive seeds brachytherapy after the failure of platinum-based doublet chemotherapy DIAGNOSIS:: The patient was diagnosed with left lower lung cancer with mediastinal lymph node metastasis by chest computed tomography.

INTERVENTIONS

Initially, apatinib alone was used as second-line cancer therapy. Subsequently, the patient received concurrent apatinib and iodine-125 radioactive seeds brachytherapy.

OUTCOMES

The patient achieved partial response shortly after undergoing treatment with only apatinib. During the treatment, the tumor continued to respond to apatinib therapy, and the lung metastases were diminished eventually. However, a chest computed tomography scan showed a large cavity in the lung tumor. Thereafter, the patient received concurrent apatinib and iodine-125 radioactive seeds brachytherapy. Unfortunately, she died due to pulmonary infection.

CONCLUSION

Apatinib alone may be a good second-line therapy for advanced lung cancer patients who are refractory to platinum-based doublet chemotherapy. However, its potential benefits, especially as combination therapy, need further investigation by future prospective clinical studies. Elderly patients with advanced lung cancer may benefit from concurrent apatinib with iodine-125 radioactive seeds brachytherapy when chemotherapy is not tolerated or effective. Further studies are needed to investigate the clinical outcomes and toxicities associated with concurrent apatinib and radiation therapy in patients with advanced lung cancer.

Efficacy and safety of CT-guided 125I brachytherapy in elderly patients with non-small cell lung cancer

Non-small cell lung cancer (NSCLC) has become the most common cancer type and the leading cause of cancer-associated mortality worldwide. The aim of the present retrospective study was to evaluate the efficacy and safety of computed tomography (CT)-guided ¹²⁵I brachytherapy alone in elderly patients with NSCLC. A total of 26 elderly patients with NSCLC stage I–III who had an inoperable lesion or progressive disease following radio-chemotherapy were treated with CT-guided ¹²⁵I seed implantation for lung lesions and included in the present study. The prescribed dose of ¹²⁵I brachytherapy was 80–140 Gy, and dosimetric verification was performed immediately after the procedure. The response rate (RR) and local control rate (LCR) were analyzed according to the Response Evaluation Criteria in Solid Tumors (version 1.1). Survival was estimated using the Kaplan-Meier method. Safety and complications were also documented. All patients were aged 65–85 years (median age, 77 years) and successfully completed the procedure, and the median follow-up time was 9.4 months (range, 3–31 months). After a 6-month follow-up, for pulmonary lesions, complete response (CR) was achieved in 11 (42.3%) cases, partial response in 9 (34.6%) cases, stable disease in 4 (15.4%) cases and progressive disease in 2 (7.7%) cases. The 6-month RR and LCR were 76.9 (20/26) and 92.3% (24/26), respectively. The mean overall survival (OS) time was 11.7±7.6 months and the 0.5- and 1-year OS rates were 90.1 and 73.3%, respectively. Tumor-related symptoms in patients were significantly alleviated following the procedure. No severe complications occurred during and after the procedure of ¹²⁵I seed implantation. In conclusion, CT-guided ¹²⁵I brachytherapy is a feasible, effective and safe therapy and may be considered as an alternative option to surgery and radiotherapy for elderly patients with NSCLC.

Oligorecurrence Non-small Cell Lung Cancer After Failure of First-Line Chemotherapy: Computed Tomography-Guided 125I Seed Implantation vs. Second-Line Chemotherapy

Purpose: To compare the efficacy and safety of computed tomography (CT)–guided ¹²⁵I seed implantation with second-line chemotherapy in treatment of oligorecurrence non–small cell lung cancer after failure of first-line chemotherapy.

Methods: Data of oligorecurrence non–small cell lung cancer patients after failure of first-line chemotherapy at two institutions were retrospectively reviewed from January 2013 to July 2018. A total of 53 patients who received the treatment of ¹²⁵I seed implantation or second-line chemotherapy were eligible for this study. In group A, 25 patients, 84 lesions, received CT-guided permanent ¹²⁵I seed implantation, whereas in group B, 28 patients, 96 lesions, received second-line chemotherapy. The outcomes were measured in terms of disease control rate, overall survival, quality of life, and complications.

Results: The median follow-up period was 13 months (range, 5–42 months). Disease control rate in group A was higher than that in group B (70.8 vs. 42.3%, P = 0.042) at 6 months after treatment. The median overall survival was 12.8 months (95% confidence interval, 10.5–15.1 months) in group A and 15.2 months (95% confidence interval, 12.2–18.2 months) in group B, with no significant difference (P = 0.847). Since the fourth month, the number of patients in group A with a non-decreasing Karnofsky Performance Scale score was more than that in group B (P < 0.05). The incidence of grade 3 or higher complications especially hematologic toxicity in group A was significantly lower than that in group B (P < 0.05).

Conclusion: Radioactive ¹²⁵I seed implantation is safe and feasible in selected non–small cell lung cancer patients with oligorecurrence after failure of first-line chemotherapy and seems to provide a better long-term quality of life in these patients compared with second-line chemotherapy.

Brachytherapy Combined With or Without Hormone Therapy for Localized Prostate Cancer: A Meta-Analysis and Systematic Review

Purpose: The purpose of this study was to evaluate the efficacy of brachytherapy combined with or without hormone therapy in patients with localized prostate cancer.

Methods and Materials: We systemically searched the Medline, Web of Science, Cochrane Library and Embase databases for studies published between the databases' dates of inception and February 2019. The primary endpoints were the 5-year overall survival (OS) rates, 5-year biochemical progression-free survival (bPFS) rates and 10-year bPFS rates. The results were expressed as the relative risk (RR) and 95% confidence interval (CI). Based on the heterogeneity evaluated with the I² statistic, a meta-analysis was performed using either a random- or fixed-effects model.

Results: A total of 16 cohort studies including 9,359 patients met all the criteria for inclusion in the analysis. Our data showed that brachytherapy (BT) combined with hormone therapy (HT) increased the patients' 5-year bPFS rates (RR = 1.04, 95% CI: 1.01–1.08, P = 0.005) and 10-year bPFS rates (RR = 1.12, 95% CI: 1.02–1.23, P = 0.001) compared with BT monotherapy. However, BT combined with HT did not increase the patients' 5-year OS rates (RR = 1.02, 95% CI: 0.99–1.095, P = 0.1) compared with BT monotherapy.

Conclusions: BT combined with HT can increase the bPFS rates of patients with localized prostate cancer, but it does not improve patients' OS rates.

Analysis of dose distribution between contemporary and standard planning in high-dose-rate endobronchial brachytherapy based on three-dimensional imaging

Purpose

The treatment planning (TP) in high-dose-rate (HDR) endobronchial brachytherapy (EB) can be based on various forms of imaging. In the case of lung cancer, one-dimensional or two-dimensional imaging is standard. The dose coverage of the target (planning target volume – PTV) and organs at risk (OAR) is unknown, because the doses are calculated on the basis of the dose points. In modern brachytherapy, TP can be based on three-dimensional (3D) images. A plan created in this way contains information about the dose distribution in the PTV and OAR. Treatment plans based on standard planning (SP) and contemporary planning (CP) may differ in dose distribution in the patient’s body. Those differences between SP and CP may have an effect on the dose distribution in PTV, OAR and follow-up.

Material and methods

The study involved a group of 31 patients prospectively treated with advanced, inoperable, non-small cell lung cancer. As many as 76 treatment fractions were analyzed. Firstly, the coverage of the PTV parameter in 2D and 3D for V₈₅, V₁₀₀ and V₁₁₅ was analyzed. Secondly, the dosage that OAR would take in was evaluated. In the cases of the heart, spinal cord and esophagus, the examined dosage equaled D_0.1cm³, D_1cm³ and D_2cm³ for each of the structures. Also, heart D₂₀ was examined as well as D₅ for the healthy lung.

Results

The median dose to the target volume was on average 43.33% higher for V₈₅ with the contemporary planning method when compared to standard planning, with statistical significance. This came with the cost of an OAR mean dose increase of 1 Gy in D_0.1cm³ for the heart.

Conclusions

Contemporary TP in EB allows one to adjust the dose distribution for individual clinical situations and allows one to improve clinical target volume (CTV) coverage, increase doses to the OAR and increase overall survival. The use of new methods of treatment plans in EB has significantly increased the follow-up to 21 months in a treated group of patients.

Safety and efficacy of CT-guided radioactive iodine-125 seed implantation assisted by a 3D printing template for the treatment of thoracic malignancies

OBJECTIVE

To ascertain the safety and efficacy of radioactive iodine-125 seed implantation (RISI) for the treatment of thoracic tumors.

METHODS

Clinical patients with primary or metastatic tumors in the chest treated with RISI were analyzed. The RISI process included the following stages: preoperative planning, template design and 3D printing, CT-guided RISI assisted by a template, and postoperative dosimetric verification. The prescribed dose was ≥ 80 Gy. The main analytic measures were the local control (LC) rate and toxicity.

RESULTS

From April 2015 to July 2018, a total of 92 patients, including 41 with lung cancer and 51 with lung metastases, were analyzed. The median lesion diameter was 5 cm. The median postoperative D90 was 142.6 Gy. The median follow-up was 10.7 months. The overall survival rates at 1 year and 3 years were 59.7% and 22.2%, respectively. The LC rates at 1 year and 3 years were 64.9% and 32.8%, respectively. The LC rates at 3 years for patients with D90 < 140 Gy and D90 > 140 Gy were 23.1% and 54.3%, respectively (P = 0.014). The LC rate of metastatic lung cancer was more favorable than that of primary lung cancer. The multivariate analyses showed that the dose and lesion type were independent factors for LC (P < 0.05). No factors were related to OS. The incidence of pneumothorax and hemoptysis was 35.8% and 3.2%, respectively. Few cases of radiotherapy-related toxicity effects were observed.

CONCLUSIONS

RISI may be safe and efficacious and is associated with few complications during the treatment of thoracic tumors. If patients need local treatment and surgery or radiotherapy is not available, RISI could be considered.

Radiation-related Adverse Effects of CT-guided Implantation of 125I Seeds for Thoracic Recurrent and/or Metastatic Malignancy

During radioactive Iodine-125 seed implantation (RISI), Iodine-125 radionuclide is implanted directly into a lesion and kills tumor cells by steadily emitting radiation. In our study, we analyzed the adverse effects of RISI for thoracic malignancy, and investigated the safety, dosage, and adverse effects of RISI for these cases. Between June 2007 and January 2018, 77 patients with thoracic recurrent and/or metastatic tumors who underwent CT-guided RISI were enrolled. Radiation-related adverse effects were analyzed, including pneumonia, esophagitis, hemorrhage, fistula, skin injury, heart injury, and spinal cord injury. We used the Common Terminology Criteria for Adverse Events (CTCAE) v4.03 to evaluate adverse effects and analyzed the relationship between adverse effects and dosimetric parameters of organs at risk (OAR), including D0.1cc, D2cc, Dmean, and V20. The results of the study were as follows: The median follow-up period was 11 months. The median postoperative dose (D90) was 122 Gy (45.7–241.8 Gy). Three patients (3.9%) showed radiation pneumonitis of grade ≥2. Two patients (2.6%) showed radiation-induced esophagitis of grade ≥2. One patient (1.3%) showed an esophageal fistula. Two patients (2.6%) had a tracheal fistula. Five patients (6.5%) had radiation-related skin reactions. One patient (1.3%) reported chest wall pain, while three (3.9%) showed hemoptysis. No patients showed radiation myelitis or cardiotoxicity. The mean D2cc of organs at risk were 165.7 Gy (lung), 10.61 Gy (esophagus), 10.25 Gy (trachea), 18.07 Gy (blood vessel), 12.64 Gy (heart), 14.77 Gy (spinal cord), 17.47 Gy (skin). Dosimetric parameters, such as D0.1cc, D2cc and Dmean, were higher in patients with toxic reactions (above the upper limit of 95% confidence interval among the overall data). Chi-square test showed that skin D0.1cc > 600 Gy, D2cc > 500 Gy, and Dmean >90 Gy were associated with grade ≥2 radiation dermatitis (p < 0.05), but no clear dose-toxicity correlation was found in other OARs. So, we concluded that the overall incidence of toxicity and adverse effects from RISI for the treatment of thoracic tumors is low. The dose-toxicity characteristics have not been fully defined. Doses within the upper limit of the 95% confidence interval may be considered safe. This was a retrospective analysis, and follow-up period was minimal, indicating possible limitations of this study.

Radiotherapy in the control of bleeding from primary and secondary lung tumours

This literature review clarifies the role of radiotherapy in the management of low-volume haemoptysis. Embase and Medline were interrogated, and PRISMA guidelines were then used to select relevant articles. Seventy-eight articles were considered relevant and manually reviewed. The evidence suggests that external beam radiotherapy is more effective than endobronchial brachytherapy at controlling low-volume haemoptysis. There is no evidence to recommend a combination of the two techniques. Different doses and fractionations appear equally effective, with a potential survival advantage of higher dose regimens for fitter patients. Palliative radiotherapy is effective at controlling low-volume haemoptysis. External beam radiotherapy is the first-line treatment, with endobronchial brachytherapy recommended following external beam radiotherapy failure. Choice of dose and fractionation should take into account the patient's performance status.

Bronchoscopic ablation techniques in the management of lung cancer

Central airway involvement is a common manifestation of lung cancer during the disease course. Some patients will require bronchoscopic therapeutic interventions to palliate symptoms, or less commonly to provide more definitive therapy of airway involvement. We describe an overview specifically of bronchoscopic ablative techniques that are available for use in malignant airway obstruction. Techniques that are more commonly used include bronchoscopic application of laser, electrocautery, argon plasma coagulation (APC), cryotherapy and mechanical debulking techniques. Less commonly employed are brachytherapy and photodynamic therapy. These techniques may be applied via flexible or rigid bronchoscopy depending upon the clinical scenario. The choice of technique depends on available tools and expertise, the urgency of the clinical scenario, and whether the lesion is predominately endobronchial, extrinsic compression, or a combination of both. Malignant airway obstruction is a common finding in lung cancer and there are a number of effective bronchoscopic ablative techniques that may be employed safely to palliate patients with a significant symptom burden.

Design and validation of a surgical navigation system for brachytherapy based on mixed reality

PURPOSE

An accurate position of the needle is vitally important in low-dose-rate seed implantation brachytherapy. Our paper aims to implement a mixed reality navigation system to assist with the placement of the I¹²⁵ seed implantation thoracoabdominal tumor brachytherapy needle and to validate the accuracy and quality of this type of method.

METHODS

With the surgical navigation system, based on mixed reality through a novel modified multi-information fusion method, the fusion of virtual organs and a preoperative plan for a real patient and the tracking of surgical tools in real time were achieved. Personalized image recognition and pose estimation were used to track needle punctures in real time and to perform registration processes. After a one-time registration with a hexagonal prism tracker that used an iterative closest point algorithm, all information, including medical images and volume renderings of organs, needles, and seeds, was precisely merged with the patient. Doctors were able to observe the tumor target and to visualize the preoperative plan. This system was validated in both phantom and animal experiments. The accuracy of this system was validated by calculating the positional and rotational error of each needle insertion. The accuracy of implantation of each seed was determined in an animal experiment to test the accuracy in low-dose-rate brachytherapy. The efficiency of this system was also validated through time consumption assessments.

RESULTS

In the phantom experiment, the average error of the needle locations was 0.664 mm and the angle error was 4.74°, average time consumption was 16.1 min with six needles inserted. Based on the results of the animal experiment, the accuracy of the needle insertion was 1.617 mm, while the angle error was 5.574° and the average error of the seed positions was 1.925 mm.

CONCLUSIONS

This paper describes the design and experimental validation of a novel surgical navigation system based on mixed reality for I¹²⁵ seed brachytherapy for thoracoabdominal tumors. This system was validated through a series of experiments, including phantom experiments and animal experiments. Compared with the traditional image-guided system, the procedure presented here is convenient, displays clinically acceptable accuracy and reduces the number of CT scans, allowing doctors to perform surgery based on a visualized plan. All the experimental results indicated that the procedure is ready to be applied in further clinical studies.

Safety and efficacy of 125I brachytherapy for bilateral lung recurrences from hepatocellular carcinoma after resection or ablation

PURPOSE

To evaluate the safety and efficacy of ¹²⁵I brachytherapy to treat bilateral lung recurrences from hepatocellular carcinoma (HCC) after resection or ablation.

MATERIALS AND METHODS

We retrospectively recruited 95 patients with bilateral lung recurrences from hepatocellular carcinoma (HCC) after resection or ablation who had received 3-6-month sorafenib with or without stereotactic body radiotherapy (SBRT), from October 2011 to January 2015; patients were then randomly divided into two groups, 44 patients received computed tomography (CT)-guided ¹²⁵I brachytherapy (group A), and 51 patients were treated with supportive and symptomatic treatments (group B).

RESULTS

The median survival time was 19 months (range of 3-36 months). The local response rate (LRR) at 3, 6, 12, 18, 24, 30 and 36 months in group A was 81.8%, 65.9%, 59.1%, 45.0%, 38.6%, 22.7%, 11.4%, respectively, and 64.7%, 47.1%, 33.3%, 25.4%, 15.7%, 11.7%, 7.8%, respectively, in group B (P < 0.05). The mean progression-free survival time (PFST) and overall survival (OS) of group A were significantly longer than those of group B. Alpha fetoprotein (AFP) and tumor size were independent factors that affected the PFST and OS, normal AFP levels and less than 1-cm tumor diameter had better PFST and OS (P < 0.05). No massive bleeding or serious complications occurred.

CONCLUSION

CT-guided ¹²⁵I brachytherapy is safe and effective for the treatment of bilateral lung recurrences from HCC after resection or ablation.

A Real-Time Tracking and Visualization System for Robot-Assisted Template Location Method Applied to Lung Cancer Brachytherapy

Accurate location of the puncture-guiding template, including the position and orientation, is essential for surgeons to implant radioactive seeds into an internal tumor in lung cancer brachytherapy. The objective of this paper is to establish a real-time tracking and visualization system (RTVS) to monitor the robot-assisted location process distantly and confirm the ultimate location accuracy without redundant computed tomography (CT) scans. RTVS consists of tracking and visualization components. A quaternion-based iterative closest point (QICP) algorithm for higher accuracy was proposed for the premised module of spatial registration. Arithmetic accuracy of QICP and clinical performance of RTVS were both validated by a series of experiments in a CT room. Spatial registration experiment shows that QICP consistently presents a distinctly higher degree of accuracy of 0.87±0.11 mm compared with other two conventional algorithms. RTVS, evaluated by tracking and visualization experiments, achieves a tracking accuracy of 1.05±0.05 mm position and (0.29±0.14) deg orientation. In addition, the time cost for template location is greatly reduced, so are the CT scan times. RTVS has the potential on lessening the workload of surgeons, reducing the CT radiation injury to the patient, and accelerating the progress of a brachytherapy surgery. The system presented means a new contribution to the lung cancer brachytherapy.

Clinical and endoscopic response to high dose rate endobronchial brachytherapy in malignant lung tumors: A single centre experience

Purpose

The aim of the study was to evaluate the short-term clinical, endoscopic response, and acute toxicities in endobronchial cancer treated with high-dose-rate endobronchial brachytherapy (HDR-EB).

Materials and Methods

Thirty patients of advanced endobronchial cancers were treated with HDR-EB. Brachytherapy was delivered at a depth of 1 cm from the source axis at weeks 1, 2, and 3 with 7 Gy per fraction. All patients were evaluated before treatment and at 1 month after completion of therapy. Using Speiser's scoring criteria, the severity of symptoms (dyspnea, cough, hemoptysis, and postobstructive pneumonia) and degree of obstruction were graded.

Results

Symptomatic response for cough, dyspnea, and hemoptysis was seen in 88%, 75%, and 96%, respectively, with a significant P value (<0.05). Obstructive pneumonia was resolved in 94% of patients. Endoscopic response in terms of degree of obstruction was seen in 84% of patients. Acute toxicities in the form of radiation bronchitis were seen in 32% of patients, whereas 8% of patients experienced esophagitis. Bronchospasm was seen in one patient during treatment.

Conclusion

HDR brachytherapy is a highly effective, safe, convenient therapy in alleviating symptoms of endobronchial obstruction with endoscopic response in the majority of cases. Thus, HDR-BT is a promising treatment for palliation of patients presenting with symptoms of endobronchial obstruction with an acceptable rate of complications.

Current status of brachytherapy in cancer treatment - short overview

Cancer incidence and mortality depend on a number of factors, including age, socio-economic status and geographical location, and its prevalence is growing around the world. Most of cancer treatments include external beam radiotherapy or brachytherapy. Brachytherapy, a type of radiotherapy with energy from radionuclides inserted directly into the tumor, is increasingly used in cancer treatment. For cervical and skin cancers, it has become a standard therapy for more than 100 years as well as an important part of the treatment guidelines for other malignancies, including head and neck, skin, breast, and prostate cancers. Compared to external beam radiotherapy, brachytherapy has the potential to deliver an ablative radiation dose over a short period of time directly to the altered tissue area with the advantage of a rapid fall-off in dose, and consequently, sparing of adjacent organs. As a result, the patient is able to complete the treatment earlier, and the risks of occurrence of another cancer are lower than in conventional radiotherapy treatment. Brachytherapy has increased its use as a radical or palliative treatment, and become more advanced with the spread of pulsed-dose-rate and high-dose-rate afterloading machines; the use of new 3D/4D planning systems has additionally improved the quality of the treatment. The aim of the present study was to present short summaries of current studies on brachytherapy for the most frequently diagnosed tumors. Data presented in this manuscript should help especially young physicians or physicists to explore and introduce brachytherapy in cancer treatments.