Search Results (185)

Purpose: While magnetic resonance-guided radiation therapy (MRgRT) may provide significant clinical advantages, delivery times tend to be longer than other radiation therapy (RT) modalities and published data on these times are limited. We evaluated longitudinal treatment times across our 8-year institutional MRgRT experience. Methods/Materials: A retrospective analysis of patients treated at our institution on a 0.35-Tesla MR-Linac between April 2018 and April 2026 was performed. All fractions were delivered with continuous intrafraction cine-MRI, soft tissue tracking, automatic beam gating, and online adaptive radiation therapy (oART) when indicated. The primary objective was to characterize changes in total in-room time (TIRT), treatment delivery time (TDT), and total adaptive time (TAT). For analysis of efficiency gains, our overall experience was separated into early (2018–2022) and late (2022–2026) periods. Results: A total of 1026 patients, 1203 treatment courses, and 7665 fractions were included. The median age was 69 years (range: 19–94) and the most commonly treated sites by treatment course were pancreas (n = 430; 35.7%), thorax (n = 203; 16.9%), abdominopelvic lymph nodes (n = 181; 15.0%), liver (n = 138; 11.5%), and adrenal gland (n = 83; 6.9%). The median prescription dose was 50 Gy (range: 16.0–76.0) in a median of five fractions (range: 1–36). Breath-hold and stereotactic body radiation therapy (SBRT) were used in 87.9% and 88.5% of treatment courses, respectively. From the early (2018–2022) to late (2022–2026) study period, the proportion of fractions utilizing SBRT (49.9% vs. 81.1%; p < 0.001), oART (32.9% vs. 80.2%; p < 0.001), respiratory gating (75.9% vs. 88.8%; p < 0.001), and elective nodal coverage (61.8% vs. 78.2%; p < 0.001) increased, as did the proportion of pancreatic treatments (20.4% vs. 38.4%; p < 0.001) and the utilization of single-fraction courses (3.4% vs. 10.3%; p < 0.001). Despite this increasing complexity between study periods, median oART TIRT decreased from 67.0 to 48.0 min (28.4% reduction; p < 0.001), driven primarily by a reduction in TAT from 20.0 to 7.0 min, p < 0.001. Pancreatic oART fractions showed the greatest improvement (median TIRT, 70.0 to 47.0 min; p < 0.001). In 2022–2026, 78.1% of oART fractions were completed within 60 min vs. 35.5% in 2018–2022 (p < 0.001). Conclusions: Ablative MRgRT, with or without oART, can often be delivered in 60 min or less, including for mobile and anatomically unfavorable tumors. Future software and hardware advances are expected to further improve MRgRT treatment efficiency. Full article

Background/Objectives: Stereotactic body radiation therapy (SBRT) is increasingly used for oligometastatic lung cancer. However, standard ablative SBRT (BED₁₀ of 100 Gy or higher) is not feasible when lesions abut critical organs or patients have poor performance status. This study aimed to evaluate the efficacy and safety of moderate-dose SBRT (BED₁₀ below 100 Gy but exceeding conventional palliative doses) in patients with oligometastatic lung cancer unfit for standard ablative SBRT. Methods: We retrospectively analyzed patients treated at a single institution between October 2019 and March 2025. Eligible patients had pathologically confirmed lung cancer with extracranial oligometastasis and received 25–40 Gy in 4–7 fractions. Patients with brain or bone metastases were excluded. The primary endpoint was local control. Secondary endpoints were event-free survival, disseminated disease-free survival, overall survival, and treatment-related toxicity. Results: Forty-three patients with 55 lesions were analyzed. The mean age was 66 years, and lymph node metastases were the most frequent site (69.1%). The most common regimen was 35 Gy in 5 fractions (63.6%). At a median follow-up of 14.7 months, objective response (complete or partial) was achieved in 54 of 55 lesions (98.2%). The 1-year and 2-year local recurrence-free survival rates were 89.7% and 86.9%, respectively, and the 1-year and 2-year overall survival rates were 83.2% and 56.1%, respectively. Local control differed by metastatic site, with 2-year rates of 95.5% for lymph node lesions and 56.2% for lesions of the lung and chest wall (p = 0.002), whereas smaller differences were observed by BED₁₀ and oligometastatic subtype. Treatment-related toxicities occurred in 8 of 43 patients (18.6%), all of grade 1–2, and radiation pneumonitis was the most common (9.3%). No grade 3 or higher events occurred. Conclusions: In this preliminary single-center experience, moderate-dose SBRT achieved favorable local control with acceptable toxicity in oligometastatic lung cancer patients unfit for standard ablative SBRT, supporting a risk-adapted approach. Full article

Stereotactic body radiotherapy (SBRT) is an effective and increasingly utilized treatment modality for abdominal tumors, offering high rates of local control with generally acceptable toxicity profiles. Nevertheless, rare but severe late gastrointestinal complications, including radiation-induced ulceration, may occur and significantly impair patients’ quality of life, as well as continuation of oncologic treatment. Hyperbaric oxygen therapy (HBOT) has shown potential benefit in the management of chronic radiation-induced tissue injury, although evidence regarding its role following SBRT remains limited. We report the case of a 75-year-old woman with cholangiocellular carcinoma who developed severe radiation-induced duodenal ulceration following liver SBRT, presenting with persistent postprandial pain, nausea, vomiting, and substantial weight loss despite standard supportive treatment. Helicobacter pylori testing was negative, non-steroidal anti-inflammatory drug use was excluded, and histopathology showed chronic inflammatory and fibrotic mucosal injury with reactive epithelial changes. Despite high-dose proton pump inhibition, bismuth subcitrate, and nutritional support, symptoms and endoscopic ulceration persisted. HBOT was administered at 2.4 atmospheres absolute for 60 min over 30 sessions. Clinical improvement was noted after three sessions, and treatment was completed without adverse effects. Follow-up endoscopy demonstrated almost complete ulcer regression, with complete symptom resolution, improved oral intake, and a 10 kg weight gain. To the best of our knowledge, this represents the first reported case describing the successful use of HBOT as a potentially effective adjunctive treatment for severe radiation-induced duodenal ulceration following liver SBRT in a patient with cholangiocarcinoma. Although encouraging, this observation should be interpreted cautiously, and prospective clinical studies are needed to further evaluate the efficacy, safety, and optimal timing of HBOT in this setting. Full article

Background/Objectives: Due to its rapidly aging population, lung cancer is expected to become the second most common and deadliest cancer in Japan. Although surgery is the primary treatment for early-stage non-small cell lung cancer (NSCLC), advances in radiation therapy technology mean that stereotactic body radiation therapy (SBRT) is also a viable option for elderly patients with various underlying health conditions. Methods: We conducted a retrospective analysis to evaluate the outcomes of SBRT in 50 consecutive elderly patients (37 of whom were aged 80 and older) with early-stage peripheral NSCLC (Tis~T2aN0M0), who were treated with SBRT at our hospital and received a total dose of 55 Gy in four fractions. Results: The three-year overall, disease-free and cause-specific survival rates for all patients were 73.2%, 88.5% and 91.4%, respectively. For patients aged 80 years and older, these rates were 77.5%, 90.6% and 91.4%, respectively. There was no local recurrence. Hematogenous metastases were observed in four patients. However, hilar and subcarinal lymph node metastases developed in only one patient. Grade 2 pneumonitis and chest wall injuries (CWIs) were observed in two and five patients, respectively. Patients with larger tumors had a significantly higher incidence of chest wall injuries. Conclusions: SBRT at a total dose of 55 Gy in four fractions can achieve safe and satisfactory outcomes for early-stage peripheral NSCLC, even in patients aged 80 years and older. While CWIs were limited to Grade 2, attention to the chest wall dose is advisable when treating tumors adjacent to the chest wall. Full article

Background: The number of elderly patients with hepatocellular carcinoma (HCC) has been increasing worldwide. This study aimed to evaluate the clinical outcomes of stereotactic body radiation therapy (SBRT) for patients aged ≥80 years with solitary HCC. Methods: This retrospective study included 117 patients with solitary HCC treated with SBRT between January 2019 and June 2025 at eight institutions in Japan. Patients were categorized into the very elderly group (≥80 years, n = 41) and the control group (<80 years, n = 76). Overall survival (OS), local tumor progression (LTP), and treatment-related toxicities were evaluated. Propensity score matching (PSM) was performed to minimize baseline imbalances between the two groups. Results: The median age was 84 years in the very elderly group and 74 years in the control group. The 3-year OS rates were 79.0% in the very elderly group and 62.8% in the control group, with no statistically significant difference observed (crude cohort: 95% CI, 0.18–1.08, p = 0.072; PSM cohort: 95% CI, 0.12–1.26, p = 0.114). The 3-year LTP rates were 18.9% in the very elderly group and 15.6% in the control group, without significant intergroup differences. Acute toxicities were numerically more frequent in the very elderly group; however, no grade ≥3 toxicities or treatment-related deaths were observed. Changes in ALBI score did not differ significantly between groups (p = 0.785). Conclusions: SBRT may represent a feasible treatment option with an acceptable safety profile in carefully selected very elderly patients with solitary HCC. It may be a reasonable option for this growing patient population. Full article

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with limited therapeutic options, a high mortality rate, and poor overall survival, necessitating the development of new therapeutic and diagnostic strategies. This study investigated the potential of plasma-derived small extracellular vesicles (sEVs) as a source of molecular biomarkers associated with the treatment response. Methods: Plasma samples were obtained from patients with locally advanced and borderline resectable PDAC at baseline and following neoadjuvant chemotherapy, either FOLFIRINOX (5-FU [fluorouracil], leucovorin, oxaliplatin, and irinotecan) or GEM-ABRAX ( gemcitabine plus nab-paclitaxel), followed by stereotactic body radiation therapy (SBRT). sEVs were isolated from plasma at baseline, after neoadjuvant chemotherapy, and following SBRT, and were characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), nano-flow cytometry, and real-time PCR (RT-PCR). Results: The isolated sEVs exhibited an average size of <200 nm, expressed canonical exosome markers (CD63 and CD9), and exhibited pancreatic cancer (PanC)-associated markers, including cholecystokinin A receptor (CCK-AR) and carbohydrate antigen 19-9 (CA19-9). The sEV cargo included several PanC-associated microRNAs (miRNAs). Notably, the expression profiles of these miRNAs demonstrated interpatient variability, though a subset of miRNAs showed statistically significant changes following treatment. Conclusions: These findings support the feasibility of sEV isolation and molecular profiling from patient plasma and warrant further investigation as a potential source of biomarkers in pancreatic cancer. Full article

Background/Objectives: Paragangliomas (PGLs) and pheochromocytomas (PCCs) are rare neuroendocrine tumors. While external beam radiation therapy (EBRT), particularly stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT), is established for head and neck PGLs (HNPGLs), its efficacy for non-head and neck PGLs (non-HNPGLs) and PCCs is less defined. We aimed to compare treatment outcomes of EBRT across these anatomic sites. Methods: We retrospectively reviewed patients with confirmed PGL or PCC treated with EBRT at a single institution between 1998 and 2025. Treated lesions were classified as non-HNPGL or HNPGL based on the radiation treatment field. Outcomes included local control (LC), distant progression-free survival (dPFS), overall survival (OS), symptomatic/biochemical response, and toxicity. We also conducted a systematic review examining EBRT for non-HNPGLs and PCCs following PRISMA guidelines. Results: We included 74 patients with 129 lesions who were treated with EBRT, with 62 HNPGL lesions and 67 non-HNPGL lesions. Of the non-HNPGL lesions, 50.7% (34/67) received SRS/SBRT with a median BED₁₀ of 50.8 Gy (range, 35.7–112.5). 5-year LC rate for non-HNPGL lesions was 95.3%, compared to 100% for HNPGL lesions, with 78% of lesions achieving symptomatic control. For non-HNPGL patients, median dPFS and OS were 37.6 and 131 months, respectively. There were no acute or late G ≥ 3 toxicities. Our systematic review (61 studies, 183 patients) showed LC and symptomatic improvement ranges of 76–100% and 76–94%, respectively. Conclusions: EBRT, including SRS and SBRT, provides excellent local control and symptomatic relief for both non-HNPGLs and HNPGLs. It represents a safe, effective treatment option for these rare tumors regardless of anatomic location. Full article

Purpose/Objective: This purpose of this study is to report on a cohort of patients with Early-onset pancreatic cancer (EOPC) (age < 55 years) who were treated with neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT) with or without surgical resection. Materials/Methods: This was a single-institution, retrospective review of patients with EOPC that was staged as either borderline resectable (BRPC) or locally advanced (LAPC) based on NCCN criteria and who were treated with upfront chemotherapy followed by SBRT, with or without subsequent surgical resection. Endpoints included overall survival (OS), local progression-free survival (LPFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and treatment-related toxicity. Results: From 2016 to 2021, 47 patients met the inclusion criteria. The median age was 50.4 years (range, 36.4–54.7 years). The median duration of induction chemotherapy was 4 months (range, 2.5–9.0 months). The SBRT dose for the majority (46/47, 97.9%) of patients was 33 Gy in five fractions. Surgical resection was performed in 33 patients (70.2%). The median OS, LPFS, DMFS, and PFS were 14.2 months, 11.6 months, 8.9 months, and 8.1 months respectively. Six-month and 1-year LPFS were 88.3% and 45.4%, respectively. Chemotherapy duration (≥4 months) was associated with improved median OS (16.5 vs. 10.1 months, p = 0.005), LPFS (10.1 vs. 4.9 months, p = 0.002), DMFS (9.7 vs. 5.2 months, p = 0.014), and PFS (9.7 vs. 5.2 months, p = 0.020). The normalization of CA 19-9 (≤34 vs. >34 U/mL) after chemotherapy was associated with improved median DMFS (not reached vs. 5.6 months, p = 0.003) and PFS (11.3 vs. 5.6 months, p = 0.022). Grade 3+ rates of chemotherapy and radiation-related toxicity were 14.9% and 2.1% respectively. The Clavien–Dindo 3b toxicity rate was 3.0%. Conclusions: In EOPC, an induction chemotherapy duration ≥4 months and the normalization of CA 19-9 after chemotherapy were associated with improved outcomes, suggesting a role for extended durations of systemic therapy titrated to CA 19-9 response before transitioning to local therapy. The high rate of local failure and the low rate of grade 3+ toxicity also suggest a role for intensifying local therapy in this population. Full article

Background/Objectives: Stereotactic body radiation therapy (SBRT) provides improved pain response and local control for spinal metastases. However, management of local failure after initial SBRT is challenging. We report institutional outcomes, dosimetry, and toxicity for reSBRT following SBRT. Methods: We retrospectively reviewed 61 lesions (55 patients) treated with reSBRT after prior SBRT. Both SBRT courses delivered a median dose of 27 Gy. Patients underwent clinical and radiological evaluation every three months. Toxicity was graded using CTCAE v5.0. Dosimetric parameters for the spinal cord (SC), cauda equina (CE), planning organ-at-risk volumes (PRV), and thecal sac were converted to equivalent dose in 2 Gy fractions (EQD₂) using the linear–quadratic model (α/β = 2). Results: Median follow-up was 10.3 months. Forty lesions (65%) were cervicothoracic and 21 (35%) were lumbosacral. One- and two-year overall survival (OS) were 45% and 29%, respectively, and one- and two-year local control (LC) were 89% and 88%, respectively. Gastrointestinal primary tumors were associated with inferior LC (HR 2.41, 95% CI 1.11–5.23, p = 0.026). Fifteen patients (27%) reported myelitis/neuropathic symptoms during follow-up; four (7%) developed new post-radiation myelitis or neuropathy (RMN) without radiologic progression. Five patients (9%) developed vertebral compression fractures (VCF). Cumulative EQD₂ was not significantly associated with RMN (p = 0.344); all affected patients had thecal sac EQD₂ > 95.5 Gy and relevant nerve roots EQD₂ > 108 Gy. Conclusions: ReSBRT provided a favorable LC with acceptable toxicity. High cumulative dose to the thecal sac and nerve roots may contribute to neurologic toxicity as peripheral nerve injury. Full article

Magnetic Resonance Imaging (MRI) plays a pivotal role in evaluating treatment response following radiation-based therapies for hepatocellular carcinoma (HCC). As radiation modalities such as stereotactic body radiotherapy (SBRT) and transarterial radioembolization (TARE) gain prominence, understanding the underlying mechanisms of radiation-induced cellular senescence is essential for accurate interpretation of imaging. The physiological changes of radiation treatment manifest as altered diffusion characteristics and delayed regression of enhancement and tumor volumes on MRI, challenging conventional response criteria. Herein, functional and temporal imaging biomarkers are necessary. However, current imaging strategies lack standardization and robust validation, underscoring the need for prospective studies to correlate MRI findings with treatment outcomes. This review synthesizes emerging evidence on MRI-based evaluation of radiation-treated HCC, explores the physiological rationale linking senescence to imaging phenotypes, and advocates for optimized imaging protocols and criteria to enhance post-treatment surveillance and therapeutic decision-making. Full article

Objective: Radiotherapy remodels the tumor microenvironment (TME) and may enhance the efficacy of immunotherapy in cancer treatment, particularly in patients with large, unresectable hepatocellular carcinoma (HCC) complicated by portal vein tumor thrombus (PVTT). Because of these unique effects, a growing body of research has found that stereotactic body radiation therapy (SBRT) combined with transcatheter arterial chemoembolization (TACE) or programmed death protein 1 (PD-1) inhibitors has a synergistic impact on unresectable advanced hepatocellular carcinomas (HCCs) larger than 5 cm in diameter. We aim to explore the efficacy of these treatment modalities through a network meta-analysis (NMA). Methods and Analysis: We evaluated the efficacy and safety of different SBRT-based treatment modalities for large advanced HCCs with PVTT (tumor diameter ≥ 5 cm), with primary endpoints including overall survival (OS), progression-free survival (PFS), and grade 3–4 severe adverse events (SAEs). Results: Eighteen studies comprising 2303 patients were included. SBRT combined with transcatheter arterial chemoembolization (SBRT + TACE) demonstrated significantly superior overall survival compared with other monotherapy or combination strategies. Most other treatment regimens showed comparable PFS outcomes. Notably, SBRT alone and SBRT combined with PD 1 inhibitors (SBRT + PD 1) were associated with significantly lower incidences of severe adverse events compared with other treatment modalities; all of these reported SAEs were manageable with appropriate clinical intervention. Conclusions: For patients with large (≥5 cm) advanced HCC with PVTT, SBRT combined with TACE was associated with superior OS and PFS compared with other treatment strategies. These findings suggest potential synergistic interactions between SBRT and TACE or immunotherapy. Further high-quality prospective trials are warranted to validate these observations and clarify the underlying molecular mechanisms. Our results provide evidence to inform therapeutic decision-making in advanced HCC. Full article

The integration of artificial intelligence (AI) into medicine, oncology, and radiology represents a marked shift in the diagnosis, prognostication, and management of hepatocellular carcinoma (HCC), a malignancy with high global incidence and poor prognosis. This review examines the application of AI, including machine learning (ML) and deep learning (DL), across the spectrum of HCC care. As AI advances, new convolutional neural networks (CNNs) and other models are enhancing diagnostic accuracy, reducing interpretation times, and improving the characterization of liver lesions across major imaging modalities including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). Beyond diagnosis, the transformative role of AI in prognostication is also improving, where AI can now noninvasively predict critical factors such as microvascular invasion, genetic mutation status, tumor recurrence, and treatment response. Furthermore, AI has shown promise in facilitating patient-specific treatment planning by stratifying patients for interventions such as transarterial chemoembolization (TACE) and stereotactic body radiation therapy (SBRT). The review also addresses the emerging fields of pathomics and the use of AI in positron emission tomography (PET), while critically evaluating the cost-effectiveness of these technologies. Despite its promise, the widespread clinical adoption of AI faces challenges, including limited generalizability, maintaining patient privacy, ethical considerations, and the need for robust prospective validation. Ultimately, this review illustrates that the future of HCC management lies in a collaborative, hybrid-intelligence model, where AI-driven insights augment clinical expertise to optimize diagnostic pathways, personalize therapy, and improve patient outcomes. Full article

Stereotactic body radiation therapy (SBRT) for localized prostate cancer delivers high doses per fraction, making dose constraints for the rectum and other organs at risk critical during treatment planning. This study evaluated the association between prostate–rectum separation, achieved with a biodegradable balloon rectal spacer at different anatomical levels, and corresponding organ-at-risk dose patterns. Thirty-three patients underwent transperineal balloon spacer implantation followed by SBRT to 36.25 Gy in five fractions. Prostate–rectum separation at the apex, mid-gland, and base were measured on CT and/or MRI and categorized as <10 mm, 10–14 mm, or ≥14 mm. Rectal dose–volume parameters and mean doses to the rectum, bladder, and penile bulb were assessed using linear regression analyses and group comparisons at 14 mm separation. Mean prostate–rectum separation was 16.6 mm overall, with minimal high-dose rectal exposure observed. Increasing separation was associated with reduced rectal dose–volume parameters at the apex and mid-gland, while greater base separation corresponded primarily to lower bladder mean dose. Increased apical separation was also associated with reduced penile bulb mean dose. No acute gastrointestinal toxicity was observed, and genitourinary toxicity was limited to low-grade events. These findings indicate that prostate–rectum separation varies by anatomical level and is associated with distinct organ-at-risk dose relationships in prostate SBRT. Full article

Background/Objectives: Existing literature reviews have not focused on the acute and late toxicities of non-magnetic resonance imaging (MRI)-guided adaptive radiation therapy (ART), compared the impacts of non-MRI-guided versus MRI-guided ART, or evaluated the effectiveness of adaptive conventional fractionated radiation therapy (CFRT) and stereotactic body radiation therapy (SBRT) in relation to toxicity in prostate cancer (PCa). The purpose of this scoping review was to systematically identify original articles and evaluate the impact of ART on toxicity in PCa in a comprehensive manner. Methods: A literature search was conducted using electronic databases on 17 June 2025, identifying 27 eligible papers. Results: The overall median toxicities of ART in PCa were 15.0% (acute grade 1 gastrointestinal (GI)), 1.0% (acute grade 2 GI), 0.0% (acute grade 3 GI), 47.1% (acute grade 1 genitourinary (GU)), 9.6% (acute grade 2 GU), 0.0% (acute grade 3 GU), 10.0% (late grade 1 GI), 2.0% (late grade 2 GI), 0.0% (late grade 3 GI), 29.7% (late grade 1 GU), 5.0% (late grade 2 GU), and 0.0% (late grade 3 GU). The choice of image guidance modality for ART does not appear to substantially influence toxicity; however, dedicated commercial ART systems may contribute to reducing toxicity to lower levels in PCa. Furthermore, the toxicity rates of adaptive CFRT and SBRT were comparable. Conclusions: Adaptive CFRT may be considered when SBRT is unsuitable for certain patients, without increasing the risk of side effects. However, further research is warranted to evaluate dedicated commercial cone-beam computed tomography (CT)- and CT-guided ART systems. Full article

Background/Objectives: Patients with early-stage non-small cell lung cancer (NSCLC) or limited lung metastases and compromised lung function, such as those with interstitial lung disease (ILD) or chronic obstructive pulmonary disease (COPD), or other factors rendering them high-risk for surgery or medically inoperable, face increased risks of treatment-related toxicity from stereotactic ablative radiation therapy (SABR). This study evaluated a novel treatment approach to mitigate these risks. Methods: We investigated Personalized Ultra-Fractionated Stereotactic Adaptive Radiotherapy (PULSAR), delivered as pulsed radiation every three weeks, in patients with <5 cm lung tumors and ILD, COPD, or prior therapy. Treatment occurred between 2022 and 2024. Online adaptive radiotherapy (o-ART) was employed in 20 patients (80%) to modify treatment plans when anatomical changes warranted replanning. Primary outcomes included volumetric tumor response, changes in dose to organs at risk (OARs) and acute events, while secondary outcomes included local and tumor control, and overall survival. Results: Twenty-three patients received PULSAR treatment at doses between 40 Gy and 60 Gy in 5 fractions and one patient received 54 Gy in 3 fractions, with a median follow-up time of 16.2 months. Approximately half of treated patients demonstrated volumetric tumor response, with median residual volume of 70% (range 36–100%) at maximal response. Among the 20 patients (80%) who underwent online adaptive replanning, significant reductions in OAR dosimetry were observed for all organs assessed including the Dmax for heart (p = 0.0053), bronchus (p = 0.0003), esophagus (p = 0.0005), spinal cord (p = 0.025), and the lung V20 Gy and V12.5 Gy (p < 0.0001). Treatment-related toxicity included two grade 1–2 adverse events and six grade 3 events consisting of pneumonitis, dyspnea or lung infection, with no grade 4 or 5 events. Median progression-free survival was 21.1 months, with 1-year overall survival of 74% and 1-year local control of 100%. Conclusions: PULSAR shows promise as a feasible treatment option for high-risk patients with NSCLC or lung metastases, demonstrating no grade 5 events and complete tumor control. Additional research is needed to fully evaluate the safety profile of PULSAR in the high-risk subgroups and whether PULSAR’s treatment intervals and adaptive planning advantages lead to improved long-term outcomes compared to conventional, uninterrupted SABR regimens. Full article