Strahlentherapie und Onkologie最新文献

Purpose: Total marrow (lymph-node) irradiation (TMI/TMLI) is designed to minimize toxicities of conventional total body irradiation in hematopoietic stem cell transplant conditioning. Planning typically relies on a computed tomography (CT) scan acquired many days before treatment (e.g. 15 days; CT-15) to allow time for plan optimization. However, anatomical changes during this interval, influenced by patient condition and concurrent therapies, can compromise dosimetric accuracy. This study evaluates the impact of shortening the CT-to-treatment timeframe to 4 days (CT-4) on dosimetric and positioning accuracy in TMI/TMLI.

Methods: Eighteen patients were enrolled in this prospective study (ClinicalTrials.gov: NCT04976205). Treatment plans, optimized with a multi-isocenter volumetric modulated arc therapy on CT-15, were recalculated on CT‑4 to assess changes in planning target volume (PTV) dose coverage (PTV_D98%). Image matching quality between CT-15/CT‑4 and cone-beam CT acquisitions was assessed with a scale of 1 to 5. Wilcoxon signed-rank test with significance set at p < 0.05 was considered.

Results: A significant reduction in median PTV_D98% was found between CT-15 (98.0%, minimum/maximum [98.0, 98.0]%) and CT‑4 (92.2%, [62.9, 98.9]%). Image matching quality improved in 72% of patients using CT‑4 compared to CT-15. In 11% of cases, relevant discrepancies required re-optimization using CT‑4.

Conclusions: These findings underscore the benefits of a shorter CT-to-treatment timeframe for improving dosimetric and positioning accuracy in TMI/TMLI. Automated planning tools may further enhance TMI/TMLI workflows, particularly for patients undergoing intensive conditioning protocols.

Purpose: The increasing importance of radiation oncology (RO) education worldwide drives a need for modernization of university curricula, particularly in anticipation of the new Licensing Regulation for Physicians (Ärztliche Approbationsordnung, ÄApprO) in Germany. This study evaluates RO education at four German medical schools and compares student perspectives with the recommendations of the academic radiation oncology consortium of the German Society of Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) in order to highlight gaps and opportunities for curriculum improvement.

Methods: A cross-sectional survey was conducted among medical students from the universities in Aachen, Bonn, Cologne, and Düsseldorf (ABCD) from January to June 2022. The standardized digital questionnaire included 31 questions (Likert scale and open-ended items) assessing teaching quality, learning formats, and practical relevance. Descriptive and thematic analyses were performed.

Results: A total of 152 fully completed surveys were analyzed. Most students (76%) reported the use of clinical case examples, but only 13% had direct patient contact. Small-group teaching and hybrid learning formats were preferred. ABCD students emphasized the need for clearer learning objectives and improved differentiation of RO from related disciplines. While 50% supported increased semester hours, opinions were divided. Findings were largely consistent with DEGRO's recommendations, though discrepancies were observed in the organization of RO within medical curricula.

Conclusion: This study identified key areas for improving RO education, including clearer learning objectives, more interactive and clinically relevant teaching, and increased opportunities for hands-on experience. Integrating these student-informed recommendations into future curriculum reforms may enhance training quality, promote engagement, and support interest in RO as a career.

Background: Single-fraction stereotactic body radiotherapy (SBRT) is an effective treatment option for patients with non-small cell lung cancer (NSCLC) who are ineligible for surgery. This study investigates long-term clinical outcomes, prognostic factors, and toxicity associated with high-dose single-fraction SBRT.

Materials and methods: We retrospectively analyzed 110 patients with 116 NSCLC lesions treated with single-fraction SBRT between 2000 and 2023. Histologic subtypes included adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and CT-defined suspicious lesions without histological confirmation. Local control (LC), progression-free survival (PFS), and overall survival (OS) were assessed using Kaplan-Meier and Cox regression models. Toxicity was evaluated using CTCAE v4.0.

Results: The most common dose was 30 Gy, prescribed in 76.7% of lesions. Among patients who received ≥ 30 Gy, LC at 2, 3, and 5 years was 78%, 74%, and 68%; PFS was 63%, 49%, and 37%; and OS was 84%, 83%, and 60%, respectively. LC and PFS were significantly higher in patients treated with ≥ 30 Gy (p < 0.05). Acute pneumonitis occurred in 2 patients (1.8%), and 22 patients (20.0%) developed late-onset pneumonitis. Pneumonitis incidence was 26.8% in patients planned with 3D-CT, compared to 12.8% with DIBH or 4D-CT. No grade ≥ 3 toxicity was observed.

Conclusion: High-dose (≥ 30 Gy) single-fraction SBRT provides excellent long-term tumor control with minimal toxicity with NSCLC. Advanced motion management techniques were associated with reduced pulmonary toxicity. A ≥ 30 Gy dose significantly improved LC, PFS, and OS. Higher Charlson Comorbidity Index (CCI) was associated with worse OS. These findings support the use of high-dose SF-SBRT in selected patients and highlight the need for individualized treatment planning. Prospective validation is warranted.

Purpose: Total neoadjuvant therapy (TNT) combined with regional deep hyperthermia (HT) for the treatment of patients with low-lying locally advanced rectal cancer (LARC) is a promising strategy to optimize patient outcomes. However, its feasibility in a real-world setting requires evaluation, particularly regarding sphincter preservation rates and the effects on tumor response, downstaging, and treatment.

Methods: Patients with low-lying LARC who underwent TNT, including chemoradiation with regional deep HT twice weekly during chemoradiation, were evaluated with regard to sphincter preservation, downstaging, and clinical (cCR) or pathological (pCR) complete response rates. Data were obtained between 2018 and 2023.

Results: A total of 49 patients with LARC at local UICC stages II (25%), III (67%), and IV (8%) were included in the analysis. The combination of TNT and deep HT demonstrated encouraging complete remission (CR) rates, with cCR or pCR achieved in 39% of patients and significant tumor downstaging in 76% of cases. A watch-and-wait concept was applied in nine cCR cases (18%). In total, 40 (82%) patients underwent surgical resection. Sphincter preservation was achieved in 31% of the patients, corresponding to a total sphincter preservation rate of 49%. Generally, TNT in combination with HT was well tolerated with an acceptable toxicity profile.

Conclusion: Combining TNT with regional deep HT for low-lying LARC is a promising treatment strategy that improves tumor response rates, complete remission rates, and tumor downstaging while maintaining acceptable toxicity profiles. Further prospective randomized studies are warranted to confirm these findings and establish the role of HT in neoadjuvant protocols.

Purpose: Interfractional prostate displacement challenges the accuracy of the delivered dose during radiotherapy treatment. Variation in bladder volume is a key driver of this movement. A deep learning (DL) model was developed to predict daily megavoltage computed tomography (MVCT) based on bladder volume and treatment fraction, enabling patient-specific anatomic estimation in prostate radiotherapy.

Methods: This retrospective study analyzed 700 MVCT scans from prostate cancer patients treated with tomotherapy. The bladder was manually contoured on all MVCT scans, and its volume was calculated. A customized three-dimensional (3D) U‑Net model was trained to generate synthetic MVCT images using the kilovoltage computed tomography (KVCT), bladder volume, and fraction number as inputs. The model's performance was evaluated with data from 84 held-out MVCTs, using image similarity metrics including structural similarity index (SSIM), normalized cross-correlation (NCC), Dice similarity coefficient (Dice), mean absolute error (MAE), and mean squared error (MSE). Additionally, anatomic accuracy was assessed for bladder and prostate contours, applying the Dice similarity and MSD.

Results: The model demonstrated accurate MVCT predictions, evidenced by a mean SSIM ranging from 0.76 to 0.80, NCC from 0.84 to 0.89, a Dice of 0.97, and MAE and MSE values between 0.05 and 0.06 and 0.010 and 0.014, respectively. The predicted anatomy enabled bladder contouring with a mean Dice of 0.83 and mean surface distance (MSD) of 1.64 mm and prostate contouring with a mean Dice of 0.92 and MSD of 0.48 mm. Changes in bladder volume showed moderate correlation with bladder Dice, with a correlation coefficient (r = -0.50), and with MSD (r = 0.64), while the prostate contour metrics exhibited weak correlations.

Conclusion: The proposed deep learning (DL) framework demonstrated promising capabilities for anatomic prediction and contour generation using noninvasive input features. Within the context of helical radiotherapy delivered on a Radixact X9 system (Accuray Inc., Madison, WI, USA), where daily MVCT acquisition is standard practice, this approach provides a patient-specific method for estimating the anatomic configuration on the day of treatment based on the planning KVCT and bladder volume information.

Purpose: Patient care in radiation oncology is challenging. Interface problems can arise, particularly when transitioning from the inpatient to home environment. Inpatients' perception of safety regarding the upcoming discharge and their satisfaction with care were addressed in the project.

Methods: "Bridging the gaps" was an optional course for medical students in their 5th year. The study consisted of two arms-one with a home visit by medical students and the other without such a visit. Before discharge, inpatient radiation oncology patients were offered a home visit by medical students. A survey was conducted before (time point 1) and 3-5 days after discharge (time point 2) using questionnaires concerning satisfaction with care, current health status, and perception of safety. Outcome changes between time points 1 and 2 in both groups (with vs. without home visit) were compared.

Results: A total of 60 patients were interviewed. Patients which received a home visit expressed improved perception of safety after discharge, whereas patients without a home visit showed decreased perception of safety (p = 0.024 for group-difference). Both groups showed a high level of satisfaction with care, which varied between the time points. In patients without a home visit, satisfaction decreased significantly after discharge, whereas satisfaction slightly increased in patients with a home visit (p = 0.001 for group-difference).

Conclusion: Radiation oncology patients may benefit from home visits by increasing their perception of safety. Continuation and expansion of the project could strengthen the role of radiation oncology in the cross-sectoral care system.