ObjectiveThis study evaluates the impact of international observerships organized by Help Ukraine Group (HUG) on professional development, knowledge transfer, and clinical practice improvement in radiation oncology in Ukraine.MethodsA total of 50 observerships were facilitated for Ukrainian medical professionals at 14 institutions across the USA, Canada, Europe, and Australia from 2022 to 2024, including 31 radiation oncologists and medical physicists. A survey assessed their impact on oncology care, focusing on knowledge gained, lessons learned, and challenges in implementing new techniques. The primary outcome was the success score, defined as a composite score of implementing new procedures, initiating improvement projects, and knowledge dissemination efforts. Descriptive and comparative analyses examined satisfaction and success outcomes.ResultsA total of 43 respondents participated in the survey (response rate 86.0%). Twenty-eight of the responders were radiation oncology professionals (67.8% radiation oncologists, 32.1% medical physicists). The median observership duration for radiation oncology professionals was four weeks, with 96.4% also attending a professional conference. Overall satisfaction was high (mean 9.5 out of 10, median 10.0, IQR 9.0-10.0) while the success score was substantial (mean 6.1 out of 10, median 7.0, IQR 5.0-8.0). Time since certification influenced success, with ≥10 years’ experience associated with higher success scores (7.4 vs. 4.7, p=0.01). Importantly, 100% of respondents learned new procedures, 89.3% reported shifts in their clinical perspective, and 60.7% successfully implemented new techniques. Subsequent knowledge dissemination in Ukraine was substantial: 82.1% provided informal training, 60.7% delivered institutional or national presentations, 39.3% incorporated materials into lectures, and 10.7% engaged in all activities. Continued mentorship with host institutions was reported by 82.1%.ConclusionsAmid the war, international observerships advanced clinical practice, education, and procedures in Ukraine, demonstrating the resilience of its medical community and providing a model that other LMICs/UMICs can follow.

PURPOSE:This guideline provides evidence-based recommendations on the use of radiation therapy (RT) for the treatment of pancreatic cancer in a variety of clinical settings including patients with resectable, borderline resectable, locally advanced, metastatic, and symptomatic disease. METHODS:The American Society for Radiation Oncology convened a multidisciplinary task force to address 4 key questions: (1) indications for and timing of RT for patients with nonmetastatic pancreatic cancer; (2) appropriate RT dose-fractionation regimens and target volumes for nonmetastatic disease; (3) preferred RT planning and delivery techniques for nonmetastatic disease; and (4) indications for RT in the locally recurrent, metastatic, reirradiation, and palliative settings. Recommendations are based on a systematic literature review and were created using a predefined consensus-based methodology with a system for grading evidence quality and recommendation strength. RESULTS:Multidisciplinary evaluation and decision-making are recommended for all patients. For patients with nonmetastatic pancreatic cancer, RT is conditionally recommended in the preoperative and postoperative settings for resectable disease. RT is recommended preoperatively for borderline resectable disease and definitively in the locally advanced setting. For preoperative RT, conventional fractionation or moderate hypofractionation is recommended. For postoperative RT, conventional fractionation is recommended. In the definitive setting, conventional fractionation is appropriate although emerging evidence supports dose escalation using either stereotactic body radiation therapy or moderate hypofractionation. Adaptive RT is recommended for dose-escalated stereotactic body radiation therapy. Elective coverage of at-risk anatomic regions is recommended for preoperative, postoperative, and definitive RT. In the locally recurrent setting, RT is recommended for patients without prior RT and conditionally recommended for those who have previously received RT. Palliative RT is recommended for patients with bleeding, pain, and obstruction. For patients with oligometastatic and oligoprogressive pancreatic cancer, RT is conditionally recommended to metastatic lesions and the primary tumor if not previously treated with definitive local therapy. Target volumes, simulation and planning techniques, and treatment recommendations are provided. CONCLUSIONS:These evidence-based recommendations provide guidance on the optimal use of RT for pancreatic cancer. Ongoing and future studies should further refine RT indications, sequencing with other therapies, and impact on patient outcomes.

PURPOSE:To provide case-based, practical examples outlining step-by-step calculations and documentation for reirradiation (reRT) evaluation. The representative examples demonstrate the application of the Reirradiation Collaborative Group (ReCOG) consensus for dosimetric assessment and reporting in reRT and illustrate how these standards can be implemented in clinical practice. METHODS AND MATERIALS:Two spine reRT cases were selected. Cumulative organ-at-risk doses were assessed using 3 approaches: direct point dose summation, point dose summation within overlap regions, and image registration-based 3-dimensional dose summation. Step-by-step calculations were performed for each approach, and new dose objectives for subsequent planning iterations were derived and compared. RESULTS:The example reRT cases detail the special medical physics consult process, highlighting different cumulative dose estimation strategies depending on the availability of voxel-based equieffective dose calculation and visualization tools. Selection of an assessment strategy should balance clinical resources with patient-specific considerations. Calculation and visualization of equieffective dose distributions facilitate cumulative dose assessment and strengthen image registration-based methods. If 3-dimensional equieffective dose calculation is not available, anatomically corresponding volumes and doses in each plan contributing to the cumulative dose in the areas of overlap can be determined manually to improve the accuracy of point dose-based summation. CONCLUSIONS:The case examples demonstrate how to apply the ReCOG consensus for dosimetric assessment and reporting in reRT and illustrate multiple strategies for cumulative dose evaluation. This work supports patient care and contributes to enhancing the field's knowledge and delivery of safer reRT.

Supplemental Figure 1: Liver metastases promote cancer progression in patients.

The primary curative therapies for hepatocellular carcinoma are resection or liver transplantation. For patients requiring downstaging or who are unresectable at presentation, the landscape of local treatment options has vastly changed over the past decades. This change is partly due to the paucity of high-level evidence to guide the selection of liver-directed therapies, where physician preference and treatment patterns have historically resulted in relegating external-beam radiation therapy (EBRT) to a secondary option in the treatment of hepatocellular carcinoma in cases where arterially directed therapies or thermal ablations were not possible. However, technology advancements have substantially improved the ability to treat liver malignancies with high doses of radiation therapy and to minimise doses to uninvolved hepatic parenchyma and other nearby organs. These advancements have enabled safe treatment of hepatocellular carcinoma with EBRT, with low risk of toxicity. Recent randomised trials support the role of EBRT in the treatment of hepatocellular carcinoma from early to advanced stages. These trials identified that EBRT improved several key patient-centred outcomes, including overall survival when using stereotactic body radiotherapy and sorafenib compared with sorafenib alone in unresectable hepatocellular carcinoma, recurrence-free survival with the use of adjuvant EBRT in select patients after hepatocellular carcinoma resection, and quality of life for patients with painful hepatocellular carcinoma masses treated with palliative EBRT. With emerging high-quality evidence, hepatocellular carcinoma therapeutic guidelines should include the growing role of EBRT in improving the quality and quantity of life for patients with liver cancer.

e16457 Background: Patients with inoperable stage II-III pancreatic cancer commonly undergo sequential stereotactic body radiation therapy (SBRT) and chemotherapy. However, there is variability in clinical outcomes, and the predictors of high-risk patients with rapid tumor progression (within 3 months) and poor overall survival (OS) despite treatment are not well characterized. We developed a radiomic (imaging-derived features) signature (RS) that predicts rapid progression. We then investigated clinical characteristics, including pathologic features and treatments received, and RS in a combined analysis to develop and validate the highest-performing model to predict OS from the time of SBRT initiation. We identified the most predictive feature from the combined model that best predicts OS. Methods: In our retrospective study, we examined a cohort of 124 stage II-III pancreatic cancer patients who underwent sequential SBRT and systemic chemotherapy and had pre-treatment pancreatic protocol computed tomography (CT) imaging. We examined 10 clinical features and extracted 900 radiomic features from each segmented tumor per patient using PyRadiomics. Dividing our cohort into training and test sets (60:40), we built a prediction model for rapid tumor progression using radiomic data on the training set (n = 74), applying a LASSO-based algorithm for feature selection and 5-fold cross-validation for parameter optimization. We validated the model performance on the held-out test set (n = 50) and generated the RS for predicting rapid progression. We examined the performance of clinical features and RS in predicting OS in univariate and multivariate Cox regression models. Results: Analysis on our cohort (57 men, 67 women; mean age 67 ± 11 years) generated a 43-feature RS that predicted rapid tumor progression (AUC 0.83, 95% CI: 0.70–0.94) in the test set. High RS was a significant predictor of mortality with hazard ratio (HR) 2.22 (95% CI: 1.32–3.73, p = 0.003) within the first year and 2.85 (95% CI: 1.35–6.03, p = 0.006) thereafter. Non-intensive chemotherapy increased only early mortality risk (HR 1.95, 95% CI: 1.08–3.53, p = 0.03), while older age was significant in later years (HR 1.80, 95% CI: 1.02–3.15, p = 0.04). Conclusions: CT-derived RS accurately predicted rapid tumor progression in stage II-III pancreatic cancer patients undergoing SBRT sequentially with chemotherapy. High RS was the strongest prognostic indicator for increased mortality risk, suggesting its utility for guiding treatment or selection for clinical trials.

Radiation therapy (RT) for locally advanced pancreatic cancer (LAPC) continues to be controversial. Advances in both systemic therapy and RT techniques have changed the landscape of LAPC management in recent years. Clinical outcomes of ablative RT have been encouraging, and randomized clinical trials may clarify the role of RT for LAPC. We present a contemporary critical review of key aspects regarding optimal patient selection, radiation dose escalation techniques, novel radiosensitizers and radioprotectors, and treatment response assessment for LAPC.

BACKGROUND:Anal squamous cell carcinoma is a rare cancer with increased occurrence of multiple cancers before and after the anal squamous cell carcinoma diagnosis. However, there are limited data on this aspect. This multi-institutional analysis aimed to define the occurrence of malignancies before and after anal squamous cell carcinoma, time trends, and impact on survival and to identify prognostic factors. METHODS:Initial primary malignancy was defined as a malignancy occurring before the anal squamous cell carcinoma. Second primary malignancy was defined as a distinct primary cancer that developed after anal squamous cell carcinoma diagnosis. Retrospective multi-institutional chart review was done. Progression-free survival (PFS), overall survival, and prognostic factors were evaluated. RESULTS:A total of 647 patients with anal squamous cell carcinoma treated with curative intent were analyzed. Median age was 61.2 years with 72% as females. Of these, 150 (23.3%) patients had multiple malignancies with initial primary malignancy in 16% and second primary malignancy in 8%. Patients without prior cancer had better 5-year PFS (81.2% vs 67.2%, P = .011) and overall survival (81% vs 69%, P = .008) compared with those with prior cancer. Second primary malignancies had a statistically significant adverse impact on PFS (hazard ratio [HR] = 4.22) and overall survival (HR = 3.56). Females had better 5-year PFS (82% vs 70%, P = .016) as compared with males. The median time interval for developing anal squamous cell carcinoma (as second primary malignancy) after initial primary malignancy was 9.32 years. CONCLUSIONS:Anal squamous cell carcinoma patients have an increased risk of multiple malignancies. These patients who have prior cancers have inferior outcomes. Second primary malignancy is a poor prognostic factor in patients with anal cancer. Second primary malignancy can develop years after treatment of primary anal squamous cell carcinoma.

Supplemental Figure 5: Liver metastases enhance neutrophil migration and function.

Purpose This study aimed to identify predictors of global liver function change measured by albumin-bilirubin (ALBI) score following stereotactic body radiation therapy (SBRT) in patients with hepatocellular carcinoma (HCC). By integrating gadoxetic acid-enhanced magnetic resonance imaging (MRI) uptake and dosimetric data, the goal was to develop functional-based treatment-planning strategies that preserve hepatic function. Methods and Materials Twenty-five patients with HCC enrolled on an institutional review board-approved adaptive SBRT trial had liver dynamic gadoxetic acid-enhanced MRI and blood sample collections before and 1 month after SBRT. Gadoxetic acid uptake rate (k1) maps were quantified for regional hepatic function and coregistered to both 2-Gy equivalent dose and physical dose distributions. Mean or integral-based metrics, dose-volume or function-volume histogram metrics, and function-dose-volume histogram metrics were calculated. These metrics were correlated with percentage ALBI score changes by Spearman rank correlation with Bonferroni correction. Results We found that the greater the sparing of liver with high-hepatic function (k1 intensity), the less the decline of ALBI score post-RT. The threshold for preserving global hepatic function was 10 % of the maximum k1 intensity and 5 Gy EQD2. The integration of regional function (k1) and dosimetric data improved the ability to predict ALBI score changes compared with dosimetric or functional data alone. Conclusions Combining regional liver function metrics from gadoxetic acid-enhanced MRI with radiation dose provides a robust model for predicting ALBI score changes following SBRT. These findings suggest that there is a potential for functional-based treatment planning to better preserve liver function in patients with HCC undergoing SBRT. Future studies are needed to externally validate these findings.

Purpose: Inflammatory bowel disease (IBD) has been considered a relative contraindication to radiation therapy (RT) because of the potential greater risk of RT-induced toxicities. This study aimed to assess acute toxicity outcomes in patients with IBD treated with abdominal/pelvic RT. Methods and Materials: After institutional review board approval, patients with IBD who received RT to the abdomen/pelvis were identified from an institutional research repository, and their electronic medical records were reviewed. The IBD cohort was matched 1:1 with controls according to all of the following: RT, gender, disease site, age, and year of RT. Acute toxicity was defined as toxicity occurring within 3 months of RT. Primary outcomes were assessed via univariable logistic regression models and the predicted probability of acute toxicity and acute gastrointestinal (GI) toxicity were plotted for the most significant covariates. IBD and control cohorts were compared on demographic and toxicity variables using x2/Fisher exact tests and Kruskal-Wallis tests where appropriate. Results: We identified 62 patients with a median age of 64 years (IQR, 54-70 years) who received RT from 2006 to 2022. Patients were treated with intensity modulated RT (38; 61.3%), 3-dimensional conformal RT (12; 19.4%), and stereotactic body RT/brachytherapy (12; 19.4%). After RT, 28 (45.2%) and 23 (37.1%) patients experienced grade >2 acute (any) and acute GI toxicity, respectively. Higher overall RT dose and RT dose to small bowel were found to be significantly associated with increased risk of grade >2 acute toxicities (OR, 1.041 per unit Gy; 95% CI, 1.005-1.084; P = .034 and OR, 1.046; 95% CI, 1.018-1.082; P = .003, respectively). Between IBD and control cohorts, there were no significant differences in grade >2 acute (any) and acute GI toxicities (P = .710 and P = .704, respectively). Conclusions: In patients with IBD treated with abdominal/pelvic RT for malignancy, RT was effective and well-tolerated. RT treatment planning should carefully consider the location(s) of IBD inflammation and dose to bowel structures, in particular, dose to the small bowel. (c) 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Supplemental Figure 4: Liver metastases augment neutrophils to promote cancer progression.

BACKGROUND AND PURPOSE:As patients with rectal cancer with clinical complete response (cCR) after neoadjuvant therapy may be safely spared Total Mesorectal Excision (TME), strategies to maximize cCR are needed. MATERIALS AND METHODS:We conducted a single-arm phase II study to determine whether dose-escalated short-course radiotherapy (25 Gy/5 fractions + 5 Gy/1 fraction boost) followed by eight cycles of FOLFOXIRI increased cCR rates among adult patients with > T2N0M0 or low T2N0 rectal cancer. RESULTS:Between 2020 and 2023, we enrolled 37 patients, of whom 27 (73 %) had at least one high-risk feature (cT4, extramural vascular invasion [EMVI], N2, threatened circumferential resection margin, positive lateral node). At primary endpoint assessment, nine (24 %) patients had cCR on both endoscopy and MRI, and pursued organ preservation (OP). Fourteen (38 %) patients had cCR only on endoscopy, nine of whom pursued OP. Of the 18 patients who pursued OP, nine had local regrowth at two years from radiotherapy start, with two-year TME-free survival of 26 %. Baseline factors significantly associated with not achieving OP included age < 50 years and T4 disease. At mid-treatment restaging, patients who achieved OP were significantly less likely to have persistent node positivity, EMVI, and endoscopically visible tumor. Grade 3+ adverse events at least possibly attributed to chemotherapy and radiotherapy occured in 51% and 43% of patients, respectively. CONCLUSION:Short-course radiotherapy with a boost followed by FOLFIXIRI results in OP in one-quarter of patients with high-risk rectal cancer, with poorer response among younger patients and T4 disease. Mid-treatment response may help guide timely decision-making regarding treatment.

PURPOSE:Reirradiation (reRT) has become increasingly prevalent due to an aging population and advancements in cancer detection and treatment. However, the field is still lacking standardized dosimetric evaluation methods and reRT workflows, which leads to difficulty in correlating clinical outcomes with delivered dose. This study reports on the implementation and evolution of a standardized reRT workflow in the Department of Radiation Oncology at University of Michigan, describing insights gained from nearly 3000 external beam reirradiation courses delivered since 2017. METHODS AND MATERIALS:A systematic workflow for reRT special medical physics consultations (SMPCs) was established in 2017. Patient SMPC records from the past 7 years were reviewed, with an additional more in-depth review of the past 1 year, to report on course characteristics including treatment sites, where prior treatment was delivered (in-house vs an outside institution), whether institutional dose limits were met and the associate reasoning, time intervals between RT, the type of dose summation method used (rigid image registration-based vs point dose-based), as well as the evolution of this workflow. RESULTS:Of the 2929 SMPCs conducted from 2017 to mid-2024, the most common treatment sites for reRT were the pelvis, brain, and thorax. About a third of patients had prior treatments at outside institutions. Of the 427 courses treated in the past year, institutional reirradiation dose limits were met in 82.2%. Rigid image registration was most successful for calculating composite dose in the brain (93.8% of cases) and least successful in the abdomen and pelvis (53.1% and 51.2%, respectively), and most reRT cases (80.3%) had a single prior course of treatment. Several updates were made to our institutional reRT dosimetric evaluation template, including increasing some time-dependent tissue recovery factors, adding and removing some OARs, and adding new point-based and volumetric dose objectives. CONCLUSIONS:On the basis of our 7 years of experience with nearly 3,000 courses of reRT, we highlight the critical need for standardized reirradiation workflows, improved tools for cumulative dose assessment, and standardized reporting. These efforts will facilitate cross-institutional data sharing to enhance data-driven clinical decision-making and improve patient outcomes in reRT. As the prevalence of reRT rises, these efforts are vital for advancing safe and effective cancer care.

PURPOSE:With the results of several recently published clinical trials, this guideline focused update provides evidence-based recommendations for the indications and dose-fractionation regimens for neoadjuvant radiation therapy (RT), optimal sequencing of RT and systemic therapy in the context of total neoadjuvant therapy (TNT), and considerations for selective omission of RT and surgery for rectal cancer. METHODS:The American Society for Radiation Oncology convened a multidisciplinary task force to update 3 key questions that focused on the role of RT for patients with operable rectal cancer. The key questions addressed (1) indications for neoadjuvant RT, (2) selection of neoadjuvant regimens, and (3) indications for consideration of a nonoperative management (NOM) or local excision approach after definitive/preoperative chemoradiation. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for quality of evidence grading and strength of recommendation. RESULTS:For patients with stage II-III rectal cancer, neoadjuvant RT was strongly recommended; however, among patients deemed at lower risk of locoregional recurrence, consideration of omission of neoadjuvant RT was conditionally recommended in favor of neoadjuvant chemotherapy with a favorable treatment response or upfront surgery. For patients with T3-T4 and node-positive rectal cancer undergoing neoadjuvant RT, a TNT approach was strongly recommended. Among patients with higher risk of locoregional recurrence, TNT with chemotherapy before or after long-course chemoradiation was strongly recommended, whereas TNT with short-course RT followed by chemotherapy was conditionally recommended. For patients with rectal cancer for whom NOM is a priority, concurrent chemoradiation followed by consolidation chemotherapy was strongly recommended. Selection of RT dose-fractionation regimen, sequencing of therapies, and consideration of NOM should be determined by multidisciplinary consensus and based on disease extent, disease location, patient preferences, and quality of life considerations. CONCLUSIONS:The task force proposed recommendations to inform best clinical practices on the use of RT for rectal cancer with strong emphasis on multidisciplinary care. Future studies should focus on further addressing optimal treatment regimens to allow for more personalized recommendations based on individual risk stratification and patient priorities regarding quality of life.

OBJECTIVE:To examine the optimal method of assessing response to neoadjuvant therapy (NAT) in patients with operable pancreatic ductal adenocarcinoma (PDAC). BACKGROUND:PDAC response to NAT is measured with biochemical, radiographic, and pathologic parameters, which can often be discordant with each other. METHODS:Patients with PDAC undergoing resection after NAT at a single institution were retrospectively analyzed. Tumor response was assessed using pre/post-NAT carbohydrate antigen 19-9 (CA19-9) levels, radiographic decrease in tumor diameter, and pathologic tumor regression grade. The association of these factors with overall survival (OS) was compared using Kaplan-Meier, Cox regression, and recursive partitioning analysis, a machine learning technique that can validate prediction models for complex hierarchical relationships. RESULTS:From 2011 to 2022, 225 patients underwent pancreatectomy after NAT (Folfirinox, 70%; gemcitabine + nab-paclitaxel, 19%; radiation, 18%). Almost half required vascular resection (portal vein, 39%; celiac axis 8%). Improved OS was observed after CA19-9 decrease >50% (32 vs 24 months, P = 0.0028), but not after major pathologic (tumor regression grade: 0-1, P = 0.067) or radiographic response (tumor diameter decrease >30%, P = 0.89). However, recursive partitioning analysis identified that the coexistence of biochemical and major pathologic response (achieved in 9% of patients) was associated with the longest OS (40 months, P = 0.0086). This optimal dual response combination was more commonly observed after neoadjuvant radiotherapy was used after systemic chemotherapy (45% vs 11%, P < 0.001). CONCLUSIONS:CA19-9 response to NAT alone is not enough to identify long-term postresection PDAC survivors. The coexistence of CA19-9 and major pathologic response was predictive of the most optimal survival outcome.

Colorectal cancer is one of the most common malignancies in the United States as well as a leading cause of cancer-related death. Upward of 30% of patients ultimately develop metastatic disease, most commonly to the liver and lung. Untreated, patients have poor survival. Historically, patients with oligometastatic disease were treated with resection leading to long-term survival; however, there are many patients who are not surgical candidates. Innovations in thermal ablation, hepatic artery infusions, chemoembolization and radioembolization, and stereotactic ablative radiation have led to an expansion of patients eligible for local therapy. This review examines the evidence behind each modality for the most common locations of oligometastatic colorectal cancer.

74 Background: We identified computed tomography (CT)-derived radiomic features predictive of tumor progression within three months, then examined their ability to prognosticate overall survival (OS) along with clinical features in pancreatic cancer. We evaluated these features in patients with unresected pancreatic cancer who underwent stereotactic body radiation therapy (SBRT) in sequence with chemotherapy, but not surgery. Methods: In this retrospective study, we examined a cohort of 101 patients with stage II-III pancreatic cancer who underwent SBRT with sequential chemotherapy at a single institution (Stanford Health Care) between 1999-2020. From their pre-SBRT contrast-enhanced CT images with segmented tumors, delineating regions-of-interest, we extracted 900 radiomic (quantitative pixel-level imaging characteristic) features. In the first phase, we identified radiomic features that predicted rapid tumor progression within three months following SBRT. We divided the dataset into a training set (n = 53) for model development and a test set (n = 48) for evaluation. Using logistic regression with the Least Absolute Shrinkage and Selection Operator algorithm for feature selection and classification, we built a binary prediction model on the training set to identify patients at risk of progression within three months of SBRT. To fine-tune parameters, we performed five-fold cross-validation (CV) on the training set, repeating each set of parameters five times. We assessed model performance on the test set using the area under the curve (AUC). We selected the model with the best AUC, generating the predictive radiomic feature set. In the second phase, we conducted univariate and multivariate Cox regression analyses to assess the relationship between OS and individual clinical variables (age, sex, stage, vessel involvement, tumor location, performance status, body mass index, biological equivalent dose of radiation) and the radiomic feature set as high versus low risk. Results: Our cohort consisted of 48 men (mean age, 70 years ± 11 [SD]) and 53 women (mean age, 67 years ± 13 [SD]). From the first phase, 32 textural features comprised the radiomic feature set that best predicted rapid tumor progression, with mean AUCs of 0.852 (CV, n=53) and 0.814 (test, n=48). In the univariate Cox model, only the radiomic feature set was predictive of OS (hazard ratio, HR, 1.724, p=0.011). In the multivariate Cox model, radiomic features and age were significant predictors of OS, with HR of 1.819 (p=0.007) and 1.024 (p=0.024), respectively. Conclusions: CT-derived radiomic features predict rapid tumor progression following SBRT, confer nearly a twofold increase in mortality risk, and, along with patient age, enhance the identification of patients with stage II-III pancreatic cancer with poor OS. [Table: see text]