International Journal of Radiation Oncology Biology Physics最新文献

Background: Historically, ocular melanomas and other eye cancers accounted for a substantial share of proton therapy patients. Although the number of proton facilities in the USA increased rapidly in the last decade, as of 2025, only roughly 1 out of 6 had active ocular proton therapy (OPT) programs. Despite the robust growth in the number of proton treatments overall, eye treatments in the USA appear to have peaked in 2016.

Purpose: To identify barriers to the expansion of the availability of hypofractionated proton therapy for ocular cancer patients.

Methods: A questionnaire was designed and distributed to proton facilities in the USA to query the level of interest in eye treatments and the challenges to establishing and supporting ocular programs. The responses were analyzed separately for the Adopters representing active programs, and the Aspirants who were not yet offering OPT.

Results: Proton therapy facilities now operate in half of the USA states. However, OPT is currently delivered in only 7 states. The use of pencil beam scanning application for ocular treatments is on the rise, as older facilities employing scattering techniques work to upgrade their beamlines. Despite a substantial interest at many facilities in developing ocular treatments on general-purpose beamlines, the lack of commercialized solutions and information on best practices has been identified as a barrier. Specific areas were identified with the most acute lack of currently available guidance.

Conclusions: Access to OPT is lagging that of proton therapy in general. Limited local accessibility, relative to alternative treatments, likely contributed to the stagnation in proton patient numbers. As the experience on non-dedicated beamlines at Adopter facilities grows, it is timely and important for the community, comprising both practitioners and vendors, to guide and facilitate establishment of new ocular programs, while maintaining the high standard of care for which OPT is known.

Purpose: PD-1 inhibitors have improved metastatic non-small cell lung cancer (NSCLC) prognosis. Stereotactic ablative body radiotherapy (SABR) may enhance immunity. This study evaluated the activity and safety of adding SABR to first-line immunotherapy post chemotherapy with nivolumab for metastatic NSCLC.

Methods and materials: NIVORAD(ALTG14/002/CT0135/TROG 16.01) randomized adults(1:2) to nivolumab 240mg 2-weekly until disease progression or prohibitive toxicity either alone, or with single fraction SABR(18-20Gy). Eligible patients had metastatic NSCLC, had progressed after 1-2 lines of chemotherapy, were immunotherapy-naïve, and had a disease site suitable for SABR. The primary endpoint was progression free survival (PFS) at 6 months. Secondary endpoints were objective tumor response rate (OTRR), overall survival (OS), PFS at 1 and 2 years, and adverse events (AEs). The planned sample size of 120 was to provide 80% power with a 1-sided type 1 error rate of 5% to distinguish the observed proportions alive and progression free at 6 months. The study closed early because of slow accrual.

Results: Fifty participants were recruited and randomly assigned to nivolumab alone (n=16) or nivolumab plus SABR (n=34). Baseline characteristics were balanced across treatment arms, apart from percentage females which was higher in the control arm (56% vs 35%). Median follow-up was 26 months. PFS was similar among those assigned nivolumab plus SABR versus nivolumab alone (PFS at 6 months 49% vs 44%, HR=0.68, 95%CI 0.36-1.27, p=0.23). OTRR (8/34[24%] vs 4/16[25%]) and OS (HR=0.86, 95%CI 0.43-1.75, p=0.69) were also similar in the two treatment groups. Rates of serious Grade 3 to 5 AE (12/16 (75%) vs 24/31 (77%) in experimental arm) were also similar in the two groups. There were two deaths, one in each treatment group (pneumonitis and respiratory failure).

Conclusion: Nivolumab plus SABR demonstrated similar efficacy and safety to nivolumab alone in metastatic NSCLC progressing after chemotherapy, without increased AEs.

Purpose: To clinically validate fully automated intensity-modulated proton therapy (IMPT) planning for head and neck cancer (HNC) through blinded comparison with manual plans by experienced radiation oncologists (ROs).

Methods and materials: Thirty patients with HNC treated with a manually created IMPT plan were retrospectively included. Dose prescription was 7000 cGy (relative biologic effectiveness) to the primary tumor and 5425 cGy (relative biologic effectiveness) to the bilateral elective nodal volumes. Fully automated IMPT plans were generated using Erasmus-iCycle, applying the same clinical 4-beam configuration and dose constraints. Three experienced HNC ROs independently assessed the automated and corresponding manual plans in a blinded manner. Each RO evaluated both plans, blinded to the planning method, to determine clinical acceptability and indicate their preference, if any. Interobserver differences in preference were evaluated using pairwise McNemar tests. A generalized linear mixed model was used to assess overall preference for automated plans.

Results: All 30 automated IMPT plans were considered clinically acceptable, whereas 28 of the 30 manual plans were rated clinically acceptable by all 3 ROs. In 28 out of 30 cases, the ROs unanimously (P = 1.00 between each pair of observers) preferred the automated plan. In the remaining 2 cases, 1 of the 3 ROs had no preference. The manual plan was never preferred. The overall preference for automated plans over no preference was statistically significant (P< .001). Target coverage was considered equivalent, whereas target conformality and sparing of both serial and parallel organs at risk were generally rated superior in the automated plans.

Conclusions: All fully automated IMPT plans for HNC were considered clinically acceptable by experienced HNC ROs. Automated plans were unanimously preferred over manually created plans in nearly all cases, with statistical significance, highlighting the clinical potential of automated IMPT planning tools.

Background: Thoracic stereotactic ablative radiotherapy (SABR) is an effective treatment for lung tumors. We evaluated the association between tumor control and A) tumor respiratory motion and motion management approach and b) single fraction dose metrics in patients treated on a prospective clinical trial.

Methods: We evaluated 235 patients with 277 thoracic tumors treated on the iSABR trial. Motion management approaches included motion inclusive (MI, 41%), MI with extreme breaths excluded (MI-EE, 13%), expiratory gating (Exp Gating, 24%), and inspiratory breath hold (IBH, 22%). Association between tumor motion, motion management technique and local recurrence (LR) was evaluated using Fine-Gray Analysis. Among the cohort of patients treated in a single fraction (150 tumors), we performed a tumor control probability (TCP) analysis for dose to the gross tumor (GTV) and planning treatment volumes (PTV).

Results: There was no significant difference in LR by tumor motion when dichotomized to < or ≥ 1 cm (3-year LR of 5.8% vs 6.3%, p = 0.98). Similarly, there was no difference in LR between patients treated with MI, MI-EE, Exp Gating, and IBH with 24-month estimates of 5.5%, 5.9%, 4.7% and 3.7%, respectively (p = 0.75). For tumors treated with single fraction SABR, GTV D_68.3% and PTV D_65.3% had the strongest correlation with local control (LC). TCP analysis demonstrated a statistically significant association with GTV D_99.7%, D_95%, and D_68.3%. Rates of LC at 3-years were greater than 90% with a GTV D_68.3% > 29.4 Gy and a GTV D_95% > 28.1 Gy.

Conclusions: These findings suggest motion management techniques including Exp Gating and IBH can adequately control for respiratory motion. Furthermore, single fraction SABR with 25 Gy resulted in high rates of LC for small tumors when using heterogenous dosimetry including 29.4 Gy to 68.3% of the GTV and 28.1 Gy to 95% of the GTV.

Regenerative medicine is an emerging field of medicine focusing on development of novel therapies to repair, replace, or regenerate damaged cells and tissues. Mesenchymal stem cell (MSC) use to promote tissue repair in a variety of injury and disease states, is one promising area of regenerative medicine. Herein we review the fundamental stem cell biology of MSCs, their use in treatment of radiation injury to internal organs, cutaneous injury and specifically, cutaneous radiation injury. We also highlight publicly available clinical case reports where MSCs have been used in treatment of acute cutaneous radiation injury. The utility of differentially sourced MSCs, MSCs vs. MSC products and various MSC treatment plans are also explored.

Purpose: Clinical target volume (CTV) delineation for involved-site radiation therapy (ISRT) in Hodgkin lymphoma (HL) is time-consuming because of the need to analyze multi-timepoint positron emission tomography (PET)/computed tomography (CT) scans coregistered to the planning CT. Our goal was to develop automated CTV segmentation algorithms that integrated multimodality imaging to facilitate ISRT planning.

Methods and materials: This study included planning CT, baseline PET/CT (PET1), and interim PET/CT (PET2) scans from 288 pediatric patients with high-risk HL enrolled in the Children's Oncology Group AHOD 1331 trial. Data from 58 patients across 24 institutions were held out for external testing, while the remaining 230 cases from 95 institutions were used for model development. We investigated 3 deep learning (DL) architectures (SegResNet, ResUNet, and SwinUNETR) and evaluated the impact of incorporating PET1 and PET2 images along with the planning CT. Performance was assessed using the Dice similarity coefficient (DSC) and 95% Hausdorff distance (HD95). Interobserver variability was estimated by comparing original institutional CTVs with those newly delineated by 4 radiation oncologists on 10 cases. The quality of CTVs generated by the top-performing model was independently assessed by radiation oncologists in 40 other cases using a 5-point Likert scale and compared against the original institutional CTVs.

Results: In the external cohort, a SwinUNETR model incorporating planning CT, PET1, and PET2 images achieved the highest performance, with a DSC of 0.72 and HD95 of 34.43 mm. All models incorporating PET/CT images were significantly better (P < .01) than planning CT-only models. Interobserver variability analysis yielded a DSC of 0.70 and HD95 of 30.14 mm. In clinical evaluation, DL-generated CTVs received a mean quality score of 3.38 out of 5, comparable to original physician-delineated CTVs (3.13; P = .13) CONCLUSIONS: The DL model was able to generate clinically useful CTVs with quality comparable to manually delineated CTVs, suggesting its potential to improve physician efficiency in ISRT planning.

Purpose: This study aimed to evaluate the feasibility of using ionizing radiation acoustic imaging (iRAI) to map the delivered dose in patients receiving radiation therapy (RT) with various treatment techniques, including 3D-comformal RT (3D CRT), Intensity Modulated RT (IMRT), and Volumetric Modulated Arc RT (VMAT).

Experimental design: Patients with intra-abdominal cancer were enrolled in a prospective clinical trial after providing informed consent. Patients were treated with stereotactic body radiation therapy (SBRT) using standard clinical techniques with the addition of volumetric iRAI for real-time mapping of three-dimensional radiation dose deposition.

Results: The minimal detectable dose was approximately 10 cGy. The overall shape of the dose distribution and the location of dose deposition, as determined by iRAI, matched the corresponding treatment plan. A gamma passing rate of 75.97 ± 11.12% and 90.99 ± 6.61% with a 10 mm/10% distance to agreement/dose difference suggests good agreement between the iRAI measurement and the treatment plan in both the liver volume and the planning target volume under the current system resolution. A structural similarity (SSIM) value of 0.6284 ± 0.1678 demonstrates that the iRAI measurements have shown structural pattern agreement with the treatment plan within the planning target volume (PTV).

Conclusions: This study demonstrates the clinical feasibility of iRAI to monitor radiation dose delivery to deep targets in real-time during treatment. This information can be integrated into treatment delivery systems to improve safety and facilitate the adaptation of radiation therapy. Despite the promising results achieved with the current form of technology, limitations in detection sensitivity, reconstruction accuracy and acoustic coupling still need to be addressed.

Purpose: Based on the results of the ASCENT trial, sacituzumab govitecan (SG) has been approved for the treatment of breast cancer. With the expanding indications across multiple cancers, data on its combination with radiation therapy (RT) are needed.

Methods and materials: ATTENTION is a retrospective multicenter study from 6 French institutions. Eligibility criteria included patients with breast cancer who received RT and SG between September 2021 and January 2025. Concomitant treatment was defined as RT administered within 4 days before or after SG administration. Data were collected through an online questionnaire and centralized after medical record review, and protocol validation by the local ethics committee. The primary endpoint was safety profiles according to the Common Terminology Criteria for Adverse Events, version 5.0. Secondary endpoints included treatment response, evaluated according to Response Evaluation Criteria in Solid Tumors, version 1.1 criteria and/or clinical symptom improvement. Assessment was performed 4-12 weeks after RT.

Results: Fifty-five patients (63 lesions) were included. The median age was 56 years (37-82). SG and RT were administered concurrently in 37 lesions (median, 3 days), sequentially in 26 lesions (median, 10 days). Subtypes included human epidermal growth factor receptor 2 (HER2)-/hormone receptors (HR)- (30%), HER2-/HR+ (27%), HER2-low/HR+ (24%), HER2-low/HR- (18%), and HER2+ (2%). SG was given as second-line in 16%, and ≥ fourth-line in 54%. RT was symptomatic in 57% and for progression in 43%, mostly targeting bone (49%) and brain (32%), using 3D conformal RT (52%), stereotactic body RT (40%), or intensity modulated RT (8%). With a median follow-up of 7.9 months (1.7-35.4), RT-related toxicities of grade 1-2 occurred in 17 cases (27%), (3 dermatitis, 4 esophagitis, and 1 brain radionecrosis). No grade ≥ 3 toxicity occurred with concomitant SG. The overall response rate was 25% complete and 80% partial responses. Median overall survival was 12.9 months (95% CI, 7.97-17.77).

Conclusions: ATTENTION is the largest study that confirms the feasibility and promising efficacy of concurrent treatment, pending confirmation in prospective trials.