The Potential of Heavy-Ion Therapy to Improve Outcomes for Locally Advanced Non-Small Cell Lung Cancer

American Radium Society Appropriate Use Criteria Systematic Review and Guidelines on Reirradiation for Non-Small Cell Lung Cancer Executive Summary

Definitive thoracic reirradiation can improve outcomes for select patients with non-small cell lung cancer (NSCLC) with locoregional recurrences. To date, there is a lack of systematic reviews on safety or efficacy of NSCLC reirradiation and dedicated guidelines. This American Radium Society Appropriate Use Criteria Systematic Review and Guidelines provide practical guidance on thoracic reirradiation safety and efficacy and recommends consensus of strategy, techniques, and composite dose constraints to minimize risks of high-grade/fatal toxicities. Preferred Reporting Items for Systematic Reviews and Meta-Analyses systematic review assessed all studies published through May 2020 evaluating toxicities, local control and/or survival for NSCLC thoracic reirradiation. Of 251 articles, 52 remained after exclusions (3 prospective) and formed the basis for recommendations on the role of concurrent chemotherapy, factors associated with toxicities, and optimal reirradiation modalities and dose-fractionation schemas. Stereotactic body radiation therapy improves conformality/dose escalation and is optimal for primary-alone failures, but caution is needed for central lesions. Concurrent chemotherapy with definitive reirradiation improves outcomes in nodal recurrences but adds toxicity and should be individualized. Hyperfractionated reirradiation may reduce long-term toxicities, although data are limited. Intensity modulated reirradiation is recommended over 3D conformal reirradiation. Particle therapy may further reduce toxicities and enable safer dose escalation. Acute esophagitis/pneumonitis and late pulmonary/cardiac/esophageal/brachial plexus toxicities are dose limiting for reirradiation. Recommended reirradiation composite dose constraints (2 Gy equivalents): esophagus V60 <40%, maximum point dose (Dmax) < 100 Gy; lung V20 <40%; heart V40 <50%; aorta/great vessels Dmax < 120 Gy; trachea/proximal bronchial tree Dmax < 110 Gy; spinal cord Dmax < 57 Gy; brachial plexus Dmax < 85 Gy. Personalized thoracic reirradiation approaches and consensus dose constraints for thoracic reirradiation are recommended and serve as the basis for ongoing Reirradiation Collaborative Group and NRG Oncology initiatives. As very few prospective and small retrospective studies formed the basis for generating the dose constraint recommended in this report, further prospective studies are needed to strengthen and improve these guidelines.

Accelerated Hypofractionated Radiotherapy for Locally Advanced NSCLC: A Systematic Review From the International Association for the Study of Lung Cancer Advanced Radiation Technology Subcommittee

INTRODUCTION

Accelerated hypofractionated radiotherapy has gained increasing interest for locally advanced NSCLC, as it can potentially increase radiobiologically effective dose and reduce health care resource utilization. Nevertheless, there is sparse prospective evidence supporting routine use of accelerated hypofractionation with or without concurrent chemotherapy. For this reason, the International Association for the Study of Lung Cancer Advanced Radiation Technology Subcommittee conducted a systematic review of prospective studies of accelerated hypofractionation for locally advanced NSCLC.

METHODS

A systematic search was conducted on Ovid MEDLINE, Ovid EMBASE, Wiley Cochrane Library, and ClinicalTrials.gov for English publications from 2010 to 2024 for prospective clinical trials and registries investigating accelerated hypofractionated radiotherapy defined as more than 2 Gy delivered in 10 to 25 fractions for nonmetastatic locally advanced (stage III) NSCLC.

RESULTS

There were 33 prospective studies identified that met the criteria for inclusion. Of 14 prospective studies evaluating definitive accelerated hypofractionation (without concurrent chemotherapy), there were six prospective registries, seven phase 1 to 2 trials, and one phase 3 randomized clinical trial, with a median dose of 60 Gy delivered in a median of 16 fractions, median progression-free survival of 6.4 to 25 months, median survival of 6 to 34 months, and 0% to 8% severe grade ≥3 esophagitis. There were 19 studies evaluating accelerated hypofractionated chemoradiation with platinum doublet-based chemotherapy as the most common concurrent regimen. Of these accelerated hypofractionated chemoradiation studies, there were 18 phase 1 to 2 trials and one prospective registry with a median radiation dose of 61.6 Gy delivered in a median of 23 fractions, median progression-free survival of 10 to 25 months, median survival of 13 to 38 months, grade ≥3 esophagitis of 0% to 23.5%, and grade ≥3 pneumonitis of 0% to 11.8%.

CONCLUSIONS

Despite the increasing use of accelerated hypofractionation for locally advanced NSCLC, the supporting randomized evidence remains sparse. Only one randomized clinical trial comparing 60 Gy in 15 fractions with 60 Gy in 30 fractions without concurrent chemotherapy did not reveal the superiority of accelerated hypofractionation. Therefore, the use of accelerated hypofractionated radiotherapy should be approached with caution, using advanced radiation techniques, especially with concurrent chemotherapy or targeted agents. Accelerated hypofractionated radiotherapy should be carefully considered alongside other multidisciplinary options and be further investigated through prospective clinical trials.

Research Progress of Heavy Ion Radiotherapy for Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) has a high incidence and poses a serious threat to human health. However, the treatment outcomes of concurrent chemoradiotherapy for non-small-cell lung cancer are still unsatisfactory, especially for high grade lesions. As a new cancer treatment, heavy ion radiotherapy has shown promising efficacy and safety in the treatment of non-small-cell lung cancer. This article discusses the clinical progress of heavy ion radiotherapy in the treatment of non-small-cell lung cancer mainly from the different cancer stages, the different doses of heavy ion beams, and the patient's individual factors, and explores the deficiency of heavy ion radiotherapy in the treatment of non-small-cell lung cancer and the directions of future research, in order to provide reference for the wider and better application of heavy ion radiotherapy in the future.

Anthropomorphic lung phantom based validation of in-room proton therapy 4D-CBCT image correction for dose calculation

PURPOSE

Ventilation-induced tumour motion remains a challenge for the accuracy of proton therapy treatments in lung patients. We investigated the feasibility of using a 4D virtual CT (4D-vCT) approach based on deformable image registration (DIR) and motion-aware 4D CBCT reconstruction (MA-ROOSTER) to enable accurate daily proton dose calculation using a gantry-mounted CBCT scanner tailored to proton therapy.

METHODS

Ventilation correlated data of 10 breathing phases were acquired from a porcine ex-vivo functional lung phantom using CT and CBCT. 4D-vCTs were generated by (1) DIR of the mid-position 4D-CT to the mid-position 4D-CBCT (reconstructed with the MA-ROOSTER) using a diffeomorphic Morphons algorithm and (2) subsequent propagation of the obtained mid-position vCT to the individual 4D-CBCT phases. Proton therapy treatment planning was performed to evaluate dose calculation accuracy of the 4D-vCTs. A robust treatment plan delivering a nominal dose of 60Gy was generated on the average intensity image of the 4D-CT for an approximated internal target volume (ITV). Dose distributions were then recalculated on individual phases of the 4D-CT and the 4D-vCT based on the optimized plan. Dose accumulation was performed for 4D-vCT and 4D-CT using DIR of each phase to the mid position, which was chosen as reference. Dose based on the 4D-vCT was then evaluated against the dose calculated on 4D-CT both, phase-by-phase as well as accumulated, by comparing dose volume histogram (DVH) values (D_mean, D_2%, D_98%, D_95%) for the ITV, and by a 3D-gamma index analysis (global, 3%/3mm, 5Gy, 20Gy and 30Gy dose thresholds).

RESULTS

Good agreement was found between the 4D-CT and 4D-vCT-based ITV-DVH curves. The relative differences ((CT-vCT)/CT) between accumulated values of ITV D_mean, D_2%, D_95% and D_98% for the 4D-CT and 4D-vCT-based dose distributions were -0.2%, 0.0%, -0.1% and -0.1%, respectively. Phase specific values varied between -0.5% and 0.2%, -0.2% and 0.5%, -3.5% and 1.5%, and -5.7% and 2.3%. The relative difference of accumulated D_mean over the lungs was 2.3% and D_mean for the phases varied between -5.4% and 5.8%. The gamma pass-rates with 5Gy, 20Gy and 30Gy thresholds for the accumulated doses were 96.7%, 99.6% and 99.9%, respectively. Phase-by-phase comparison yielded pass-rates between 86% and 97%, 88% and 98%, and 94% and 100%.

CONCLUSIONS

Feasibility of the suggested 4D-vCT workflow using proton therapy specific imaging equipment was shown. Results indicate the potential of the method to be applied for daily 4D proton dose estimation.

Dosimetric evaluation of 4D-CBCT reconstructed by Simultaneous Motion Estimation and Image Reconstruction (SMEIR) for carbon ion therapy of lung cancer

PURPOSE

Motion management is critical for the efficacy of carbon ion therapy for moving targets such as lung tumors. We evaluated the feasibility of using four-dimensional cone beam computed tomography (4D-CBCT) reconstructed by Simultaneous Motion Estimation and Image Reconstruction (SMEIR) for dose calculation and accumulation in carbon ion treatment of lung cancer.

METHODS

Motion-compensated 4D-CBCT images were reconstructed with the SMEIR algorithm to capture the most updated anatomy and motion with an updated interphase motion model on the treatment day. Projections of all CBCT phases were simulated from the planning 4D-CT by the ray tracing technique. Treatment planning and dose calculation were performed with a GPU-based Monte Carlo dose calculation software for carbon ion therapy. The treatment plan was optimized on the average computed tomography (CT) to obtain optimal intensity of the carbon ions. From the optimized plan, dose distributions on individual phases of 4D-CT and 4D-CBCT were calculated by the Monte Carlo-based dose engine. Dose accumulation was performed on 4D-CBCT images using deformable vector fields (DVF) generated by SMEIR. The accumulated planning target volume (PTV) dose based on 4D-CBCT was then compared to the accumulated dose calculated on 4D-CT, where the DVFs between different phases were obtained by the demons deformable registration algorithm.

RESULTS

Dose value histograms (DVH) as well as absolute deviations of the maximum dose ( Δ D max ), mean dose ( Δ D mean ), and dose coverage metrics ( Δ V 95 % and Δ V 100 % ) for PTV were quantitatively evaluated for the two sets of plans. Good agreement was found between the 4D-CT and 4D-CBCT-based PTV-DVH curves. The average values of Δ D max , Δ D mean , Δ V 95 % , and Δ V 100 % calculated between the 4D-CT and SMEIR-4D-CBCT-based plans were 1.91 % , 3.55 % , 2.12%, and 1.15 % , respectively, for the PTVs of ten patient case studies.

CONCLUSIONS

Based on these results, SMEIR-reconstructed 4D-CBCTs can potentially be used for motion estimation, dose evaluation, and adaptive treatment planning in lung cancer carbon ion therapy.

Effects of crystallographic and geometric orientation on ion beam sputtering of gold nanorods

Nanostructures may be exposed to irradiation during their manufacture, their engineering and whilst in-service. The consequences of such bombardment can be vastly different from those seen in the bulk. In this paper, we combine transmission electron microscopy with in situ ion irradiation with complementary computer modelling techniques to explore the physics governing the effects of 1.7 MeV Au ions on gold nanorods. Phenomena surrounding the sputtering and associated morphological changes caused by the ion irradiation have been explored. In both the experiments and the simulations, large variations in the sputter yields from individual nanorods were observed. These sputter yields have been shown to correlate with the strength of channelling directions close to the direction in which the ion beam was incident. Craters decorated by ejecta blankets were found to form due to cluster emission thus explaining the high sputter yields.