Radiation Oncology最新文献

Background: High-dose prescribed radiotherapy has been attempted to improve local control and restore portal vein in patients with hepatocellular carcinoma (HCC) complicated with portal vein tumor thrombus (PVTT). The aim of this study was to evaluate feasibility of real-time tumor-tracking magnetic resonance imaging-guided radiotherapy (rtMRgRT) for PVTT in HCC. In addition, prognostic factors for overall survival (OS) and progression pattern after radiotherapy (RT) were analyzed.

Methods: We retrospectively reviewed the data of 34 patients who had unresectable HCC complicated with PVTT and who were treated with rtMRgRT using hypofractionated radiotherapy (HFRT) and stereotactic body radiation therapy (SBRT) between June 2019 and October 2023. HFRT was performed with a total of 50-60 Gy in 10 fractions, and SBRT was performed in a range of 36-50 Gy in 4-5 fractions. The median biologic effective dose with an a/b ratio of 10 was 100 Gy₁₀ (range: 68.4-100 Gy₁₀).

Results: Twenty-one patients (61.7%) had an objective response (complete response and partial response) to PVTT; the 1-year estimated local control rate was 77.7%. The median progression-free survival and OS were 5.2 and 10.6 months, respectively. The predominant initial pattern of progressive disease after RT was outfield intrahepatic progression (21/29 cases, 72.4%). RT responder (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.12-0.88; p = 0.026) and combined transarterial chemoembolization (TACE) within 1-month post-RT (HR, 0.24; 95% CI, 0.08-0.73; p = 0.012) were favorable prognostic factors for OS.

Conclusions: The rtMRgRT demonstrated feasibility in treatment of PVTT with favorable overall response and local control. Response to RT and combined TACE within a month post-RT were favorable prognostic factors for OS. Given the predominant patterns of disease progression after RT, timely management of HCC outside RT field may be crucial for enhancing the survival of patients with PVTT undergoing RT. The early combination of TACE within a month post-RT may be beneficial in this regard. Further prospective studies are needed to determine the optimal sequencing and timing for combining RT and other local therapies in patients with PVTT.

Purpose: Pelvic nodal irradiation is often used for high-risk prostate adenocarcinoma. A commonly used alternative to low dose rate (LDR) brachytherapy, a 3-fraction SBRT boost with fiducial tracking may allow for better coverage of extracapsular extension and macroscopic seminal vesicle invasion. This study evaluates the practical impact of prior pelvic nodal irradiation on fiducial tracking during a subsequent 3-fraction robotic stereotactic body radiation therapy (SBRT) boost for high-risk prostate cancer and compares these outcomes to a cohort of patients undergoing definitive 5-fraction SBRT.

Methods: In this institutional analysis, we prospectively collected fiducial tracking data for patients receiving a 3-fraction boost to the prostate and seminal vesicles after conventional nodal radiation. We also identified patients treated with 5-fraction SBRT with a low risk of nodal involvement. Monte Carlo estimates of the Fisher's Exact Test assessed fiducial tracking loss. Continuous variables within the 5- and 3-fraction cohorts were compared using the Mann-Whitney Test. Changes in fiducial tracking and their association with pre-treatment factors were analyzed through the Kruskal-Wallis test and Monte Carlo for tracking patterns, and Spearman Correlation Coefficient and Mann-Whitney Test for deviations in tracking over 5 fractions.

Results: A total of 405 patients were treated from April 2021 to September 2023 with: (1) 5-fraction SBRT (n = 309, 76%), and (2) 3-fraction boost after nodal irradiation (n = 96, 24%). There was no significant fiducial tracking loss over the three-fraction boost treatment regimen that proceeded nodal treatment (p = 0.63). However, there was a significant (p < 0.001) loss of fiducial tracking fidelity as demonstrated by progressive loss of one tracked fiducial over 5-fractions. There was significantly more volatility observed in the 5-fraction versus 3-fraction boost treatment (median volatility 2.4 vs. 0.0, p < 0.001). There were no significant associations between fiducial tracking, independently for 3- or 5-fractions, using either analysis method or volatility for ADT, time from fiducial placement to SBRT, CTV, and QOD vs. daily SBRT.

Conclusions: Pelvic nodal treatment does not affect the quantity/quality of fiducial tracking in 3-fraction treatments. However, 5-fraction treatments showed a progressive loss and increased volatility in fiducial tracking over time. No pre-treatment factors significantly influenced fiducial tracking changes in either cohort, though ADT use trended towards increased volatility in the 5-fraction group. With a minimum of 4 fiducials placed for treatment, the loss/volatility of a single fiducial had no clinical impact on the tracking system.

Purpose: To optimize an animal model of acute radiation-induced esophagitis (RIE) in C57BL/6 mice and characterize the histopathological features of RIE at different stages.

Materials and methods: C57BL/6 mice were subjected to single thoracic X-ray irradiation at doses ranging from 5 to 30 Gy. Changes in body weight, daily food and water intake, and survival were monitored and compared within 2 weeks after radiation exposure. Epithelial damage to the esophagus, apoptosis, and inflammation at different times after irradiation were examined to characterize the pathological process of RIE.

Results: The incidence of acute RIE was strongly correlated with increasing radiation dose across all the experimental groups. No deaths were observed in mice that received 5 or 10 Gy of irradiation, whereas complete mortality was observed within 15 days after exposure to 30 Gy of irradiation. The mice in 20 Gy irradiation group had a low mortality rate. The peak of esophageal tissue damage occurred at Day 7 and was healed by Day 14 after exposure to 20 Gy of thoracic irradiation. The pathology of RIE was induced by radiation-induced DNA damage, apoptosis, reactive oxygen species (ROS), and mitochondrial impairment.

Conclusions: In this study, we found that a single 20 Gy thoracic irradiation was the optimal dose to establish acute RIE in C57BL/6 mice. Acute esophageal injury peaked on Day 7 after radiation, and the process of regeneration and repair was complete within 14 days. This work may be a useful reference for experimental research concerning RIE.

Background: Precise delineation of gross tumor volume (GTV) is fundamental for effective radiation therapy in low-grade skull base meningiomas. Magnetic resonance imaging (MRI) serves as the primary imaging tool but may not fully represent tumor extent. This study investigates the additional value of incorporating Somatostatin receptor (SSTR)-directed PET/CT in radiation therapy planning.

Methods: A retrospective analysis was conducted with four experienced radiation oncologists contouring GTVs for skull base meningiomas using MRI alone (GTV_MRI), PET/CT alone (GTV_PET/CT), and both modalities combined (GTV_ALL). Consensus ground truth volumes were generated for each modality through a STAPLE algorithm. Agreement between modalities, excluding observer variability, was assessed using statistical metrics including Dice Similarity Coefficient (DSC), Jaccard Index (JCI), Hausdorff distance (HD95), Geographical Miss Index (GMI), sensitivity, and kappa statistics.

Results: The study included 25 patients (15 females, 10 males; median age 56 years (range: 23-74 years), with 96% achieving local control post-radiotherapy over a median follow-up of 64 months (range: 28-135 months). Substantial interobserver agreement was observed, with median kappa values of 0.74 for GTV_MRI, 0.68 for GTV_PET/CT, and 0.77 for GTV_ALL. Median consensus volumes were 6.65 cc (MRI_STAPLE), 7.21 cc (PET_STAPLE), and 6.73 cc (ALL_STAPLE). The median GMI for MRI_STAPLE compared to ALL_STAPLE was 0.18 (IQR: 0.11-0.39), and 0.21 (IQR: 0.15-0.28) for PET_STAPLE compared to ALL_STAPLE. The DSC indicated the lowest concordance between MRI_STAPLE and PET_STAPLE with a median of 0.75 (IQR: 0.59-0.82), followed by PET_STAPLE versus ALL_STAPLE with a median DSC of 0.84 (IQR: 0.79-0.89), and MRI_STAPLE versus ALL_STAPLE with a median DSC of 0.89 (IQR: 0.76-0.92). The integration of PET/CT with MRI significantly enhanced concordance metrics.

Conclusion: Combining MRI and PET/CT improves GTV delineation in low-grade skull base meningiomas, as PET/CT can reveal regions missed by MRI, which may slightly underestimate tumor size. This multimodal imaging approach enhances consensus and supports its role in radiotherapy planning. Standardized protocols and technical integration remain key future goals.

Background: Radiation oncology is increasingly turning to Artificial Intelligence (AI) - and in particular Chat Generative pre-trained transformer (ChatGPT) - for decision support, patient education, and workflow efficiency. Despite promising gains, questions about accuracy, General Data Protection Regulation (GDPR)-compliance and ethical use persist, especially in high-stakes cancer care. To clarify real-world attitudes and practices, we surveyed members of the German Society of Radiation Oncology (DEGRO) on their use, perceptions, and concerns regarding ChatGPT across clinical, research, communication, and administrative tasks.

Methods: An anonymous online survey was implemented via LimeSurvey platform and distributed to all members of the DEGRO in Germany, Austria, and Switzerland between April and June 2024. The 40-item questionnaire-covering demographics, radiotherapy experience, and ChatGPT's clinical, research, communication, and administrative applications-was developed through a narrative literature review, ChatGPT-assisted drafting, back-translation, expert validation, and pilot testing. Fully completed responses were used for descriptive statistics and analysis.

Results: Of 213 respondents, 159 fully completed the survey. Participants were predominantly based in Germany (92.5%), worked in university hospitals (74.2%), and identified as radiation oncologists (54.7%), with a broad range of radiotherapy experience (< 1 year: 7.5%; >15 years: 24.5%). Awareness of ChatGPT was high (94.9%), yet actual use varied: 32.1% never used it, while 35.2% employed it regularly for administrative tasks and 30.2% for manuscript drafting. Mid-career clinicians (6-10 years' experience) showed the greatest enthusiasm-44% agreed it saves time and 72% planned further integration-though all career stages (71.7% overall) expressed strong interest in formal training. Satisfaction was highest for administrative (94.6%) and manuscript support (91.7%) but lower for technical queries (66.7%). Major concerns included misinformation (69.2%), erosion of critical thinking (57.9%), and data-privacy risks (57.2%).

Conclusion: Our survey demonstrates high awareness and adoption of ChatGPT for administrative and educational tasks, alongside more cautious use in clinical decision-making. Widespread concerns about misinformation, critical-thinking erosion, and data privacy-especially among early- and mid-career clinicians-underscore the need for targeted AI training, rigorous validation, and transparent governance to ensure safe, effective integration into patient care.

Background: Stereotactic Body Radiotherapy (SBRT) has been proven to be a safe and effective alternative to surgery in patients with metastatic primary sarcoma. However, data describing tumor response in relation to the given radiotherapy dose is lacking. Therefore, this study aims at analyzing efficacy and dose-response relationship in a retrospective cohort.

Methods: Patients with metastatic sarcoma treated with ablative SBRT and followed up at the Karolinska University Hospital between 2008 and 2021 were included. SBRT was delivered using an inhomogeneous dose distribution resulting in higher median doses within the planning target volume (PTV) than the dose prescribed. Local control (LC), progression-free survival (PFS), overall survival (OS), adverse events and dose-response relationship were assessed. Statistical analysis was performed to identify variables that correlate to outcome.

Results: Forty-three patients with a total of 83 lesions were treated. The most frequent histology was leiomyosarcoma (44%). The most common site of metastases was the lung (84%), followed by the liver (11%). The median prescription dose was 45 Gy (range 30-56 Gy) delivered in 3 fractions (range 2-8) with a planned median CTV mean dose of 309 Gy in EQD₂ with α/β = 3 Gy. The local control at 1-year, 2-year and 5-year from SBRT treatment was 97, 93 and 84%, respectively. For tumors with a planned mean CTV dose above EQD₂ 278.8 Gy (corresponding to 60.3 Gy in 3 fractions) the 1, 2 and 5-year local control was 100, 100 and 93%, respectively. Tumors planned with a lower dose than EQD₂ 278.8 Gy (α/β = 3 Gy) had a 1, 2 and 5-year local control of 90, 70 and 52%, respectively. The difference in local control between the high dose and low dose groups was statistically significant (p < 0.001). The median OS for all patients was 43 months. When respecting dose constraints, there were only limited number of mild side effects.

Conclusion: In this analysis a strongly significant dose-response relationship with excellent LC rates and limited side effects for patients with metastatic lesions of sarcoma were seen. These results could be related to the inhomogeneous dose distribution of SBRT treatments utilized in this study.

Objective: In this study we examined the correlation between standardized uptake value (SUV) of [¹⁸F]fluorodeoxyglucose (FDG) and apparent diffusion coefficient (ADC) within the gross tumor volume (GTV) of patients with head and neck squamous cell carcinoma (HNSCC). In addition, we assessed the comparability of cell density (ρ) estimates obtained from FDG PET and MRI data.

Methods: Twenty-one HNSCC patients from a prospective FMISO imaging trial underwent pre-treatment PET/CT and MRI. We assessed correlations between FDG SUV (mean, max) and ADC (mean, min) within the GTV using Pearson's correlation coefficient. The tumor cell density within the GTV was calculated from FDG SUV and from ADC maps. For the estimation of ADC-based cell density, we used a published tumor cell volume fraction (v_TC). Agreement between FDG- and ADC-derived cell density estimates was assessed. The best-fitting v_TC* was computed to achieve equal mean ρ_ADC and ρ_FDG for each patient and was compared to the literature.

Results: The SUV and ADC metrics showed up to moderate negative correlations, but none of them were statistically significant at p < 0.05. The correlation of SUV_mean vs. ADC_mean with Pearson's correlation coefficient r = -0.426 and p = 0.054 and SUV_max vs. ADC_min with r = -0.414 and p = 0.062 suggested a weak negative trend. The average and standard deviation of mean ρ_FDG and ρ_ADC across our cohort were (1.8 ± 0.6) × 10⁸ cells/ml and (3.3 ± 0.2) × 10⁸ cells/ml. The difference between the mean ρ_FDG and ρ_ADC was statistically significant (p < 0.001). To achieve equal mean ρ_ADC and ρ_FDG for each patient, the mean optimal v_TC* with standard deviation was 0.29 ± 0.09. Although significantly lower than the published mean v_TC​ (0.54), v_TC* lies within the published range of v_TC for HNSCCs (0.28 to 0.75).

Conclusion: ADC and SUV metrics exhibited moderate but marginally insignificant correlation in this dataset. Although not directly interchangeable, the two methods provide comparable, clinically relevant cell density estimates, offering flexibility to use the most accessible modality for individualized treatment planning.

Trial registration: Registered at German Clinical Trials Register on 20/08/2015 (DRKS00003830).