Strahlentherapie und Onkologie最新文献

Purpose: Ketogenic diets (KDs) have been proposed to target glycolytic cancer metabolism and synergize with radio- and chemotherapy. We herein report survival outcomes of rectal and head and neck cancer (HNC) patients who followed a KD during radio(chemo)therapy.

Methods: Thirty-five patients on a KD during radiotherapy and 46 patients on a standard diet were prospectively followed. Overall (OS), progression-free (PFS), and locoregional recurrence-free survival (RFS) were analyzed with the Kaplan-Meier method and by computing restricted mean survival times. Acute radiotherapy-induced side effects were compared using Fisher's exact test. In an exploratory analysis, patients in the KD group were matched to control patients with propensity score matching, and survival analysis was performed.

Results: Median follow-up was 77.4 (range 12.1-107.9; HNC) and 71.3 (1.5-127.1) months (rectal cancer), respectively. There were no significant differences in any survival outcome between the KD and control groups in either cohort. A numerically longer restricted mean RFS time for HNC patients did not reach the statistical significance threshold (KD: 100.5 months, 0 events; control group: 87.3 ± 7.0 months, 3 events; p = 0.059). In the propensity score-matched HNC sample, patients on a KD exhibited numerically longer OS (log-rank test: p = 0.084) and RFS (p = 0.064); however, these differences were not statistically significant. Acute skin toxicity was less severe in HNC patients on a KD (p = 0.063), which became significant in intention-to-treat analysis (p = 0.0495); all other acute toxicities were without significant differences between the groups.

Conclusion: Our analysis failed to detect a significant survival benefit of a KD during radio(chemo)therapy in HNC and rectal cancer patients, but provides further evidence for the safety of this approach.

Purpose: Ensuring reproducible treatments and therapeutic temperature rises is pivotal for wider clinical application of hyperthermia. We propose a fast automated quality assurance (QA) procedure using E‑field measurements for relative specific absorption rate (SAR) applicator characterization, with a similar workflow to radiotherapy dosimetry.

Methods: Our procedure was demonstrated for 434 MHz superficial contact flexible microstrip applicators (CFMA) with similar antennas and geometry to the ALBA ON 4000D system. Applicators were placed on a liquid saline phantom. A Cartesian robot performed E‑field measurements moving E‑field sensors through the phantom. We analysed the influence of spatial resolution on effective field size (EFS) measurements. Using volume measurements, we established effective penetration depth (EPD) variation across the aperture. We evaluated repeatability, measuring central planes on eight different days. Applicators/phantoms were characterized with flat and curved setups, using standard clinical and more excessive bolus thicknesses.

Results: Procedures take ~40 min per setup condition. One-centimetre spatial resolution appears sufficient for QA. EPD showed errors < 5% when determined from high-SAR regions (~80-90% of the maximum). The EFS and EPD variability between different days was < 5%. Increasing EPD and decreasing EFS with increasing curvature was observed when using the clinical bolus thickness, with more homogeneous SAR distributions for curved than for flat setups. Excessive bolus thickness resulted in irregular SAR distributions and larger EFS and EPD variations.

Conclusion: The proposed QA procedure is characterized by fast, practical and reproducible measurements that are suitable for efficiently evaluating various setup conditions. This flexible workflow can also be used with other radiative hyperthermia systems.

Background: In Germany, the development of evidence based medical guidelines is overseen by the Association of the Scientific Medical Societies (AWMF). Ensuring balanced representation across medical specialties and genders is essential for generating comprehensive, equitable, and unbiased treatment recommendations. This study evaluates the involvement of radiation oncology (RO) specialists and assesses gender representation within the panels of German oncological guidelines.

Methods: We analysed all oncological guidelines in the AWMF registry (n = 93/820). Data were collected from AWMF's registry, the German Society for Radiation Oncology (DEGRO) website, and affiliated organizations including the Working Group for Radiation Oncology (ARO) and the Professional Association of German Radiation Oncologists (BVDST). Gender distribution, academic qualifications, and participation rates were analysed.

Results: Of 93 oncological AWMF guidelines, RO panel members participated in 71 (76.3%), with particularly high representation in S3 (highest standard of quality and reliability) guidelines (92.5%). A total of 2795 panelists were represented in 85 analysable oncological guidelines, with 28.3% being female. Among the 255 RO panelists, the proportion of women is significantly higher with 34.5% (p < 0.05), with varying distribution across organizations: DEGRO 38.6%, ARO 31.7%, and BVDST 28.2%. Academic qualifications regarding all panelists differed significantly by gender (p < 0.001) with a high proportion of professors being male (81.3%), while women were disproportionately represented among those no academic title (62.6%).

Conclusions: RO demonstrates strong representation in German oncological guideline development, in contrast to international trends where the specialty is frequently underrepresented. Nonetheless, consistent with patterns observed across other medical disciplines and healthcare systems, gender disparities remain evident: women constitute roughly one-third of overall panel members. These findings establish an important reference point for tracking future progress toward achieving gender equity in the formulation of oncological guidelines.

Cone-beam computed tomography (CBCT) is a critical imaging modality in various medical fields, yet its repeated use poses radiation risks to patients. Low-dose CBCT image reconstruction aims to mitigate these risks while preserving image quality, which is crucial for clinical diagnosis and treatment. This review paper provides an in-depth analysis of the latest research progress in low-dose CBCT image reconstruction. We explore analytical reconstruction algorithms, iterative reconstruction algorithms, and deep learning approaches, each with distinct characteristics and applications. The paper comprehensively reviews the methods used for dose reduction in CBCT, the evolution of reconstruction algorithms, and their performance evaluations. We also identify challenges and limitations in current techniques, discussing potential future directions for low-dose CBCT reconstruction. Through a systematic literature search and analysis, this review offers a valuable reference for researchers and clinicians alike, aiming to advance the field of CBCT and enhance patient care through reduced radiation exposure and improved imaging outcomes.

Introduction: This study aimed to determine the role of postoperative adjuvant therapy in patients with thymic carcinoma following complete resection.

Methods: We conducted a retrospective analysis of patients with stage I-III or N1+ thymic carcinomas who underwent complete resection at our center between 2006 and 2020. Data on the clinical characteristics and postoperative adjuvant therapies were collected.

Results: One hundred and twenty patients were enrolled. Five (4.2%) patients received only postoperative chemotherapy, 36 (33.0%) received only postoperative radiotherapy, 75 (62.5%) received postoperative chemoradiotherapy, and four (3.3%) did not receive any postoperative therapy. During a median follow-up period of 65 months, disease failure was observed in 46 (38.3%) patients, and 28 (23.3%) patients died. The 5‑year disease-free survival (DFS) and overall survival (OS) rates were 58.7 and 81.4%, respectively. Patients who underwent different postoperative therapies exhibited varying prognoses. Radiotherapy reduced the risks of failure (p < 0.001) and death (p < 0.001), whereas chemotherapy did not (p = 0.198 and 0.260 respectively). Subgroup analyses revealed that stage III/IV patients who received chemotherapy had a lower relapse risk (p = 0.045) and improved OS (p = 0.064). Multivariate analysis demonstrated that radiotherapy alone (hazard ratio [HR], 0.24; p = 0.023) independently predicted OS.

Conclusions: Adjuvant radiotherapy should be recommended for patients with thymic carcinoma who have undergone complete resection. Further exploration is needed to clarify the role of adjuvant chemotherapy.

Introduction: Primary orbital lymphomas are predominantly low-grade subtypes, such as extranodal marginal zone lymphomas (MALT) and follicular lymphomas, which are highly radiosensitive. Mantle cell lymphoma (MCL), although less common, is an aggressive high-grade subtype with an intermediate-to-poor prognosis. While systemic therapies are standard for MCL, data on the efficacy of radiotherapy in localized orbital MCL are limited. This study evaluates the long-term outcomes of radiotherapy for localized orbital MCL using the Surveillance, Epidemiology, and End Results (SEER) database.

Materials and methods: This retrospective study analyzed cases of localized orbital MCL treated with radiotherapy between 2000 and 2021 identified in the SEER database. Demographic, clinical, and survival data were extracted. The primary endpoints were overall (OS) and cancer-specific survival (CSS), estimated using the Kapla-Meier method and Cox proportional hazards models. Statistical analyses were conducted using R software (R Foundation, Vienna, Austria), with a significance threshold set at p < 0.05.

Results: Among 13,662 patients with localized primary orbital lymphomas, 63 (0.5%) cases were histologically confirmed as MCL. Of these, 35 patients (55.6%) received radiotherapy. The age-adjusted incidence rate of orbital MCL was 0.033 per 1,000,000 person-years (95% CI: 0.025-0.042). Patients were predominantly elderly (42.9% were over 80 years old) and male (male-to-female ratio of 2.18 : 1; p = 0.012). With a median follow-up of 91 months (range: 4-237 months), the median OS was 113 months. The 5‑, 10-, and 15-year OS rates were 76.5% (95% CI: 62.7-93.4%), 48.2% (32.9%-70.6%), and 42.8% (27.4%-66.9%), respectively. Median CSS was not reached, with 5‑, 10-, and 15-year CSS rates of 98.0% (95% CI: 78.0-100.0%), 83.4% (69.5%-100.0%), and 83.4% (69.5%-100.0%), respectively. Chemotherapy did not show a significant impact on survival.

Conclusion: Radiotherapy achieves excellent long-term survival outcomes for localized orbital MCL, particularly in elderly and frail patients who may not tolerate systemic therapies. These findings support radiotherapy as an effective therapeutic option for this rare lymphoma subtype. Future multicenter studies are warranted to optimize radiotherapy protocols and improve patient outcomes.

The growing use of reduced-dose radiotherapy in patients with primary cutaneous lymphoma is a promising development. Nevertheless, the absence of controlled clinical trials to ascertain standardized doses for each specific type constitutes a significant impediment to the advancement of this field. This expert opinion strongly advocates for advancements in radiation oncology practice that address the unique complexities of primary cutaneous lymphoma. By refining our methodologies, we can optimize patient care and outcomes in this dynamic field.

Purpose: Modern involved-site radiotherapy (ISRT) for Hodgkin lymphoma decreases toxicity through reduced field sizes and radiation doses. However, in pregnancy, the therapeutic benefit has to be weighed against putative harm to the mother and the fetus, as even small doses may have deleterious effects. We conducted a phantom-based simulation to analyze uterine dose exposure from cervical and mediastinal ISRT.

Methods: Cervical and mediastinal ISRT target volumes were contoured to calculate three comparison plans (3D-conformal radiotherapy [3D-CRT], intensity-modulated radiotherapy [IMRT], volumetric intensity-modulated arc therapy [VMAT]). Thermoluminescent dosimeters (TLD) were placed within a humanoid Alderson phantom to simulate early and late pregnancy. Overall, six measurements (two for every radiotherapy plan) with 38 TLD were conducted.

Results: In early pregnancy, cervical ISRT treatment of 19.8 Gray (Gy) resulted in median fetal exposures of 8.8 mGy, 15.4 mGy, and 9.9 mGy for 3D-CRT, IMRT, and VMAT, respectively, with significant differences between the three techniques (p < 0.001) and increased doses in late pregnancy (p < 0.001). For mediastinal ISRT (19.8 Gy), early pregnancy doses were 44 mGy, 63.8 mGy, and 60.5 mGy for 3D-CRT, IMRT, and VMAT, respectively, again with significant differences (p < 0.001) and a significant increase (p < 0.001) in late pregnancy. In comparison, values of 214.2 mGy (3D-CRT), 249.9 mGy (IMRT), and 249.9 mGy (VMAT) were reached using 30.6 Gy, with significant differences between 3D-CRT and VMAT (p < 0.001), 3D-CRT and IMRT (p < 0.001), and IMRT and VMAT (p = 0.004).

Conclusion: Using RT during pregnancy may have deleterious effects on the fetus and should be deferred until after birth whenever possible. Theoretical uterine RT doses are low overall and only exceeded safety thresholds with higher-dose intensity-modulated plans. The indication for RT in pregnancy always requires careful risk-benefit consideration and individualized planning.