Practical Radiation Oncology最新文献

Purpose: A dose escalation trial of Re-irradiation (reRT) for patients with a diagnosis of recurrent GBM (rGBM) to increase the total overall dose given to the tumour without increasing toxicity. The primary objective of this study was to establish the MTD for reRT in patients with rGBM.

Methods: A phase I dose-escalation study utilizing a "3 plus 3" design aimed at identifying reRT MTD with secondary study endpoints of overall survival (OS), progression free survival (PFS), Health-Related Quality of Life (HRQOL) and neuro-cognitive outcomes. Patients with histologically proven rGBM, Karnofsky Performance Status (KPS) ≥70, and >12 months since standard CRT, were enrolled on study. Patients received daily RT, 5 fractions per week, with dose levels (DL) (total radiation dose (Gy)/number fractions): DL1 1(35/10), DL2 (42/12), DL3 (49/14). Response and progression were defined as per RANO criteria. Neurocognition and patient-reported outcomes were obtained prior to reRT, at completion of treatment and at follow-up intervals.

Results: Fourteen patients were enrolled (64% male, median KPS 80 (range 70-90), median age 54 (range 38-65)) in DL1(3), DL2(6), DL3(5). The median time between up-front RT to completion of reRT was 47.2 months (range 12.6-93.5) with patients enrolled from 2016 to 2022. Median PFS was 5.09 months (3.5, 7.2, and 5.2 months for DL 1, 2, and 3 respectively). OS was 10.3 months (6.1, 14.4, and 13.3 months for DL 1, 2, and 3 respectively). No treatment related toxicity was observed for DLs 1 and 2. In DL3, three of five patients experienced neurological decline without prior radiographic evidence of tumour and were therefore designated as grade 3 treatment-related toxicity. However, no dose limiting toxicity (DLT) was observed at any DL.

Conclusions: Results of the trial reveal 4200 cGy in 12 fractions as the MTD for the group of patients with rGBM.

Background and purpose: This study evaluates a three-step image guidance strategy (bone-prostate-rectal anterior wall alignment) to reduce posterior CTV-PTV margins in hypo-fractionated prostate radiotherapy while preserving target coverage and minimizing rectal toxicity.

Materials and methods: Twenty-three patients (575 daily CBCT scans) underwent a three-step alignment protocol: bony alignment, prostate soft-tissue matching, and rectal anterior wall fine-tuning. A dose calculation and hybrid DIR (deformable image registration)-based workflow was created to accumulate the delivered dose. A 5 mm CTV-PTV margin (0 mm posteriorly) with 70 Gy/25 fractions and strict rectal constraints was used. The DIR uncertainty has been thoroughly evaluated, covering geometric indicators, DVF physical properties, spatial uncertainty, and dosimetric uncertainty indicators. NTCP for Grade≥2 GI/GU toxicity was calculated using the Lyman-Kutcher-Burman model. Statistical comparisons employed paired t-tests or Wilcoxon rank tests (p<0.05).

Results: The DSC for CTV, rectum, and bladder exceeded 0.8, with MDA under 3mm. Jacobian determinant analysis showed biomechanical validity, with most voxels deforming within physiological ranges (92.23% for CTV, 89.63% for rectum, and 88.96% for bladder) and no non-physical deformations. The DDM varied from 0.01mm to 10.25mm, and the δ index showed a 90.04% average passing rate within the PD80%. Compared to prostate-only alignment, rectal NTCP was significantly reduced with the three-step strategy (7.95% vs. 13.61%, P<0.01), with comparable CTV coverage (D95%:69.98 Gy delivered vs. 70.98 Gy planned, P=0.08). Deformable dose accumulation confirmed adequate DIL coverage (median D100 %: 71.51 Gy), except for DILs <0.7 mm from the rectal wall, or the rectal volume overlapping with DIL_{2 cm} (DIL extends uniformly outward by 2cm) >1.5 cm³ (requiring 2-3 mm margin expansion).

Conclusions: A three-step image guidance protocol enhanced rectal protection while maintaining target coverage compared to prostate-only alignment. Reducing the posterior PTV margin preserved CTV coverage, but DIL coverage varied by location. If the DIL is less than 0.7mm from the rectum or overlaps more than 1.5cm³ within 2mm of the rectum, the reduced margin may not be suitable, potentially compromising DIL coverage, suggesting the need for personalized margins and adaptive radiotherapy to prevent underdosage.

Purpose: To develop and implement a novel number-color code system to enhance catheter identification and evaluate its effectiveness after one year of clinical use.

Methods: Radiopaque buttons with unique number-color combinations were used for freehand catheters and number tags for template-based catheters, replacing handwritten adhesive labels. A multidisciplinary survey was conducted to assess accuracy, ease of use, speed, and user confidence on a five-point Likert scale, comparing the new and previous methods. The issues encountered and suggestions for improvement were recorded.

Results: Twenty-two of 28 staff members, including five radiation oncologists, seven radiotherapy technologists, four nurses, five medical physicists, and one dosimetrist, participated in the survey. No incorrect identification was reported with either method. Personnel with direct applicator contact rated the new system higher on all aspects of freehand catheters. Medical physicists and dosimetrists also gave higher ratings but noted the radiologic invisibility of the colors and suggested shape coding. The most common issue was button positioning, particularly when locating and connecting transfer tubes. For template-based catheters, number tags were preferred over adhesive labels, although legibility issues persisted, with suggestions to enlarge tags or engrave numbers.

Conclusions: The number-color code system is simple and well-accepted by users. Further studies should define objective measures and develop more robust identification labels.

Purpose: Select patients with metastatic soft tissue sarcoma (STS) may benefit from more aggressive treatment of their primary tumor. We report on the use of combined modality treatment (CMT) using preoperative radiation therapy (RT) followed by surgery to improve local control.

Methods and materials: We retrospectively reviewed the data of 19 patients with metastatic STS consecutively treated at our institution with CMT between 2018 and 2023. All patients received moderately hypofractionated 40.05 Gy in 15 fractions followed by surgery. Patients were selected for CMT based on factors that were likely to predict longer survival despite having metastatic disease such as oligometastatic disease (≤5 lesions) and favorable response to systemic therapy.

Results: The median size of the primary tumor was 7.6 cm (IQR, 4.4-12.7 cm). Fourteen patients (74%) received systemic therapy immediately before (n = 10) or after (n = 4) CMT. Seven patients (37%) underwent additional metastasis-directed local therapy following CMT to other sites. Pain reduction after CMT was documented in 89% of patients who presented with pain (n = 8 of 9). Median follow-up was 21 months. Two-year local recurrence-free survival, progression-free/distant recurrence-free survival, and overall/cancer-specific survival were 92%, 29%, and 65%, respectively. One patient (5%) had local recurrence. For patients who were not planned to have adjuvant systemic therapy, median systemic therapy-free survival was 15 months. The rate of wound complications within 120 days of surgery was 16%. No planned adjuvant therapy was delayed because of wound complications; all patients commenced systemic therapy within 3 months of surgery. The rate of late RT toxicities was 26%; there were no grade ≥3 late toxicities.

Conclusions: For properly selected patients with metastatic STS with good performance status and long expected survival, a CMT strategy for the primary tumor with moderately hypofractionated preoperative RT offers favorable local control, low toxicity, and pain mitigation without significant effect on systemic therapy resumption.

Purpose: Standardization in clinical workflows is widely recognized as a driver of safety, efficiency, and consistency. The challenge for modern practice is determining the appropriate degree and rigidity of standardization, especially as automation and adaptive technologies reshape workflows.

Methods and materials: This Special Article synthesizes literature from radiation oncology, human factors engineering, and safety science to evaluate the balance between standardization and adaptability. We use the Law of Requisite Variety as a conceptual framework, supplemented by examples from quality assurance, adaptive radiation therapy, and emerging technologies.

Results: Well-designed standards enhance reliability, reduce variability, and facilitate training and compliance. However, excessive standardization may create brittle systems incapable of managing novel situations, whereas insufficient standardization increases variability and risk of preventable incidents. Examples illustrate how rigid quality assurance protocols can limit flexibility in addressing non-routine clinical scenarios, and how overly prescriptive adaptive workflows can hinder responsiveness to patient-specific needs.

Conclusions: Radiation oncology requires a dynamic balance between standardization and adaptability. Overstandardization can compromise resilience; understandardization can erode consistency. Applying the Law of Requisite Variety can help identify when to enforce rigid standards and when to preserve flexibility, ensuring both safety and efficiency. This approach supports informed policy-making, technology integration, and sustainable quality improvement in clinical physics practice.

For females with genitopelvic cancers, the impacts of radiotherapy on erectile tissue function and related sexual health outcomes are understudied. To inform more equitable research and clinical practice in radiotherapy, there is a need for education and a standardized approach to understand the bulboclitoris - the female erectile organ primarily responsible for arousal and orgasm. This topic discussion summarizes the literature and provides a multidisciplinary expert discussion of anatomic and physiologic considerations of the bulboclitoris within the biopsychosocial framework of female sexual function and in the context of radiotherapy. With input from anatomists, physiologists, pathologists, radiologists, radiation oncologists, and patient advocates, recommendations are provided to understand correlative functional bulboclitoris anatomy and histology, localization of bulboclitoris anatomy on CT and MR imaging, measurement of bulboclitoris-related sexual function outcomes, as well as the need for developing new dose-volume constraints to limit radiation toxicity and sexual dysfunction. These recommendations aim to promote collaborative scientific investigations related to the bulboclitoris in radiotherapy, which are crucial for generating fundamental evidence to advance prospective evaluation, prevention and mitigation strategies, to improve oncologic care and sexual health outcomes in individuals with a bulboclitoris.

Purpose: This dose-volume histogram (DVH) compendium shares the knowledge and resources compiled by disease-site experts during an immense undertaking by the Veterans Affairs (VA) and American Society for Radiation Oncology (ASTRO) to develop performance indicators for radiation therapy as part of quality surveillance. The guidance for breast, head and neck, liver, lung, prostate, and rectal cancers supports physician decision-making during dosimetric treatment planning, directs the reader to additional resources, and contributes to the evolution of DVH metrics for external beam radiation therapy.

Methods and materials: DVH tables were developed for each disease site relating to the most common dose/fractionation regimens used in VA and non-VA radiation oncology centers nationwide. Dosimetric values with validation through prior clinical data and those used in ongoing multisite trials were prioritized, with references listed in the tables. In scenarios with a paucity of data for specific constraints, the disease-site panels discussed and agreed on appropriate clinical guidance. After panel discussion, each metric was voted on to obtain panel consensus. Panel consensus was evaluated with a modified Delphi approach using a prespecified threshold of ≥75% of raters who agree or strongly agree to establish consensus via a confidential survey. Where the content did not meet this threshold, it was removed or revised. Significant revisions went back to the full disease-site panel for review, approval, and a final consensus vote.

Results: The dose constraints are the result of quality measure development between the VA and ASTRO. They represent the body of work thus far, with the goal of expanding future resources to include other disease sites. There is still work to be done to optimize dose goals and constraints for target volumes and normal tissues. Different methodologies for calculating doses have produced varying data, and ongoing efforts will harmonize the lack of concordance where possible. Wide variation when reporting on toxicities and efforts to standardize provide an opportunity for future trial data to add to the depth of knowledge. This DVH compendium is pragmatic and reflective of general practice and established treatment regimens. Having accessible default constraints supports standardization and will help improve the quality of treatment planning and radiation delivery for all patients.

Leptomeningeal disease (LMD) from solid tumors carries a poor prognosis with limited treatment options. Radiotherapy to the involved sites of LMD can provide symptomatic relief in many patients. However, selected patients may derive substantially greater benefit from treating the entire neuroaxis with cerebrospinal irradiation (CSI). Ideal candidates for CSI include patients with good performance status (KPS≥60) and either systemic disease control or effective remaining systemic therapy options. Some patients with LMD, despite being otherwise ideal CSI candidates, may present with neurologic symptoms that require urgent intervention and cannot immediately be treated with CSI. In such cases, it is feasible to urgently deliver 3D radiotherapy to an involved site for urgent symptom palliation as a "bridge" to completion CSI after initial stabilization. Using this approach allows treatment of the entire neuroaxis with minimum elective dose to help minimize the risk of rapid out-of-field recurrence that is characteristic of leptomeningeal disease treated with focal-only radiation therapy. This approach allows for rapid initiation of treatment of neurologic symptoms while a more complex CSI plan is developed.

Purpose: Image-guided stereotactic body radiation therapy (SBRT) serves as a key local treatment for liver metastases. As a next-generation technology, magnetic resonance-guided SBRT (MRgRT) offers theoretical advantages over computed tomography-guided SBRT (CTgRT) for the management of liver metastases. However, clinical evidence regarding the efficacy of MRgRT for colorectal cancer liver metastases (CRLM) remains lacking.

Methods: This retrospective study included patients with CRLM who underwent MRgRT at a single institution between September 2021 and December 2023. Local control (LC), distant hepatic control (DHC), progression-free survival (PFS), and overall survival (OS) were estimated using the Kaplan-Meier method and analyzed using statistical software (R and SPSS). Adverse events were graded according to the Common Terminology Criteria for Adverse Events version 5.0.

Results: Overall, 51 targets (planning target volumes, PTVs) in 49 patients with CRLM were treated with MRgRT. The median lesion diameter was 1.9 cm (range: 0.5-6.4 cm), whereas the median prescribed dose to the gross tumor volume was 57 Gy (range: 48-60 Gy). The median follow-up duration was 20.1 months. Among the 51 targets, 3 experienced local failure. None of the patients developed grade > 2 radiation-related toxicity. The LC rates at 12 and 24 months were 93.8% and 86.6%, respectively. The DHC rates at 12 and 24 months were 52.5% and 49.2%, respectively. The PFS rates at 12 and 24 months were 31.5% and 25.5%, whereas the OS rates at 12 and 24 months were 91.4% and 84.0%, respectively.

Conclusion: MRgRT achieved favorable LC and OS rates in the treatment of CRLM with minimal toxicity, demonstrating its potential for broader clinical application. Further studies with larger sample sizes and long-term follow-up are warranted to validate survival outcomes and assess late-onset toxicities.

Pelvic organ prolapse (POP) occurring shortly after hysterectomy is rare but may complicate adjuvant external beam radiotherapy (EBRT) in endometrial cancer. Delivering EBRT in the presence of prolapse may increase radiation exposure to adjacent organs and treatment-related toxicity, while surgical correction can delay adjuvant therapy. We describe a technically feasible, non-surgical approach using a vaginal pessary to restore pelvic anatomy and facilitate EBRT planning. Pessary-assisted repositioning improved target delineation and reduced high-dose exposure to the bladder, vagina, and rectum without delaying treatment or causing toxicity. This Technical Report highlights a simple, patient-centered strategy to optimize radiotherapy delivery in complex post-hysterectomy anatomy.