Strahlentherapie und Onkologie最新文献

Background: Radiotherapy-induced head and neck cancer harms the structural and biochemical integrity of dentin and causes mineral loss, breakdown of collagen, and increased sensitivity to radiation-induced caries and restorative failure.

Objective: To evaluate the therapeutic effectiveness of nanohydroxyapatite (nHAp) and vitamin E-individually and in combination-for remineralization and collagen matrix preservation of irradiated dentin.

Methods: Forty human third molars (n = 8 per group) were allocated into five groups randomly: non-irradiated control, irradiation-only (60 Gy linear accelerator, LINAC), irradiation + nHAp treatment, irradiation + vitamin E treatment, and irradiation + combination treatment (nHAp + vitamin E). Dentin samples were analyzed using Fourier transform infrared spectroscopy (FTIR), X‑ray diffraction (XRD), scanning electron microscopy with energy-dispersive X‑ray spectroscopy (SEM-EDX), and Vickers microhardness testing.

Results: Radiotherapy caused widespread microstructural loss and amide I and II band intensity decreases (mean of 41.3% and 47.7%, respectively) as well as a 33% loss in crystallinity. The nHAp treatment recovered phosphate peak intensity to 82.1% of the control mean, and vitamin E retained amide I and II bands at 91.3% and 88.9% of the control means, respectively. The combined treatment achieved the best recovery, with the crystallinity returning to 89.5% of the control, near full recovery of the intensities of amide and phosphate bands, normalization of the Ca/P ratio, and microhardness values that were not significantly different from the non-irradiated control (p > 0.05).

Conclusion: Nanohydroxyapatite and vitamin E have synergistic actions, promoting organic as well as mineral phases of irradiated dentin. Their combined application significantly increases microhardness, chemical composition, and ultrastructure, promoting a double-therapy strategy for the restorative rehabilitation of head and neck cancer patients after radiotherapy.

Purpose: Computed tomography (CT) scans are vital for radiotherapy planning, providing essential data for dose calculations. This study retrospectively evaluated imaging doses, scan lengths, and protocol adherence to support imaging optimization and reduce patient radiation exposure.

Methods: CT data from patients undergoing external beam radiotherapy and brachytherapy in the period 04/2021 to 12/2024 were retrieved from the institutional picture archiving and communication system (PACS). Imaging doses (volumetric CT dose index [CTDIvol] and dose length product [DLP]) were extracted from dose reports. Automated organ segmentation was used to assess standard operating procedures (SOPs) adherence by estimating anatomical scan length differences. Additional quality assurance checks assessed protocol and imaging consistency.

Results: Brain protocols exhibited the highest CTDIvol (73 ± 12 mGy), while head and neck protocols had higher DLP values (3212 ± 757 mGy·cm). The lung 4D protocol showed a higher effective dose (23 ± 9 mSv) compared to the standard lung protocol. Notable anatomical scan length differences were observed at the lower boundary in the upper abdomen (120 ± 75 mm) and spine (155 ± 159 mm), indicating opportunities for workflow improvement.

Conclusion: Enhancing CT workflows for radiotherapy patients is important and feasible. Dose and scan length analyses suggest that revising institutional SOPs, optimizing X‑ray tube modulation, and refining scan length boundaries should be considered to achieve this goal.

Background and objective: Thie study aimed to examine the economic implications of different radiotherapy fractionation schemes, specifically normofractionation (NF) and hypofractionation (HF), for breast and prostate cancer in the outpatient setting of the German healthcare system. In times of workforce shortages, limited machine availability, and rising patient numbers, the study aims to identify which fractionation approach offers the highest value in terms of efficiency and economic sustainability, aligning with a value-based healthcare framework.

Methods: Economic models were developed using German reimbursement data (EBM), treatment costs, machine usage, and realistic patient volumes. Three breast cancer fractionation schemes (conventional NF with 30 fractions, i.e., 25 fractions to the whole breast +5 boost fractions), NF with simultaneous integrated boost (SIB) comprising 28 fractions, and HF with 20 fractions (15 fractions to the whole breast +5 boost fractions) as well as two prostate cancer regimens (39 × 2.0 Gy versus 20 × 3.0 Gy) were compared. A standardized clinic setup with two linear accelerators and defined full-time staff was assumed. Analyses included cost, break-even points, contribution margins, and personnel needs in both scenarios (HF and NF).

Results: Despite lower reimbursement per case, HF regimens yielded significantly higher economic efficiency due to increased patient throughput and reduced staff-time per treatment. Over 10 years, the total revenue per linear accelerator for HF breast cancer treatments reached approximately € 56.9 million, compared to € 40.2 million and € 46.6 million for the two NF approaches. A one-time investment of € 50,000 for implementing HF (e.g., for software, training, and workflow optimization) could be amortized within a few days, depending on the scenario. Simulation models further demonstrated substantial efficiency gains under hypofractionation without the need to expand machine capacity-an important strategy amidst staffing shortages and increasing demand.

Conclusion: When supported by efficient clinic organization and sufficient patient volume, HF offers clear economic advantages over traditional fractionation schemes. However, for widespread implementation, structural reform of the current outpatient reimbursement system is desirable.

Purpose: Treatment of advanced vulvar cancer is challenging. The aim of the study was to investigate the potential of primary (chemo)radiotherapy ((C)RT) with regard to clinical outcome and associated prognostic parameters.

Methods: A total of 39 patients with squamous cell vulvar cancer receiving primary (C)RT were retrospectively identified through hospital databases. Patient and treatment characteristics as well as outcomes were assessed. Survival statistics were calculated using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test and Spearman's correlation to evaluate associations between patient or treatment characteristics and survival outcomes.

Results: Median age at diagnosis was 74 years (range 38-92 years). Patients had advanced stage disease with 28.2%/38.5% presenting with FIGO stage III/IV, respectively. All patients received external beam radiotherapy (EBRT) with a median dose to the primary tumor of 66 Gy EQD2 (range 49.6 Gy-72.6 Gy) and to lymph nodes of 53.1 Gy EQD2 (range 44.1 Gy-67.1 Gy). 69.2% received concurrent chemotherapy, mostly cisplatin weekly or mitomycin/5-fluorouracil. 10.3%/64.1% showed clinical complete remission (cCR)/partial remission (cPR) at first follow-up; 7.7% had disease progression. After a median follow-up of 25.5 months (range 0.5-132.9 months), 3‑year locoregional progression-free survival (LRPFS) and overall survival (OS) were 60.2% and 69.6%, respectively. Age and concurrent chemotherapy were the main prognostic parameters associated with improved oncological outcome.

Conclusion: Definitive (C)RT plays an important role in the management of advanced vulvar cancer with high response rates and satisfactory oncological outcomes. However, there is still room for improvement and future trials are needed to further assess the potential of definitive CRT, especially with regard to possible combinations with immunotherapy.

Purpose: In definitive radiotherapy/radiochemotherapy (RT/RCT) for localized non-small cell lung cancer (NSCLC), the introduction of positron-emission tomography (PET)-CT-based staging/RT planning and dynamic RT techniques (intensity-modulated radiotherapy, IMRT/volumetric modulated arc therapy, VMAT) were important innovations.

Methods: We performed a retrospective study and compared clinical outcomes (1) in patients with PET-CT-based staging (n = 170) vs. conventional staging (n = 103) and (2) in patients with dynamic RT techniques (IMRT/VMAT; n = 99) vs. three-dimensional conformal radiotherapy (3D-CRT; n = 64).

Results: We found improved survival with PET-CT vs. conventional staging. PET-CT patients vs. conventionally staged patients had higher applied RT doses, higher RT completion rates, and a higher rate of patients who received RCT vs. RT only. Additionally, we found higher rates of leukopenia and lung infections in PET-CT patients. When comparing RT techniques (IMRT/VMAT vs. 3D-CRT), there were no differences in survival. IMRT/VMAT patients had higher RT doses and higher rates of intensified concomitant chemotherapy (cisplatin/vinorelbine vs. low-dose cisplatin). IMRT/VMAT was associated with a reduction in pneumonitis and dermatitis.

Conclusion: In summary, refined RT/RCT strategies with PET-CT and IMRT/VMAT enable the intensification of multimodal treatment. Reduction of toxicities with IMRT/VMAT widens the therapeutic window. The coincidence of intensified treatment, improved outcomes, and higher toxicity rates in PET-CT-staged patients emphasizes the need for a detailed risk-benefit assessment during planning and application of treatment modalities.

Purpose: Radiotherapy is an important pillar of treatment for patients with locally advanced head and neck squamous cell carcinoma (HNSCC) in both adjuvant and definitive treatment. However, radiotherapy in the head and neck region is associated with relevant acute and late side effects. With the advent of modern radiotherapy and imaging techniques, numerous studies are underway to personalize radiotherapy with the aim of reducing toxicity while maintaining good control rates. Since the side effects of radiotherapy are often directly related to the irradiated volume, an important approach to individualizing radiotherapy is the reduction of elective nodal irradiation (ENI). Our aim was to provide an overview of published and ongoing studies investigating the de-escalation of radiotherapy in the elective lymphatic drainage areas of head and neck tumors.

Methods: The literature search in MEDLINE, Web of Science, and clinicaltrials.gov was conducted using the following search terms in various combinations: head and neck cancer, elective nodal irradiation, de-escalation, and radiotherapy. Studies that included nasopharyngeal cancer or carcinomas with non-squamous histology were excluded.

Results: Various approaches to deintensifying ENI have been investigated, ranging from ENI dose reduction, general dose reduction, and volume reduction to complete omission of ENI, with some studies using response-adjusted dose and/or volume reduction after induction chemotherapy or dose reduction depending on hypoxia measured by FMISO-PET scan or sentinel lymph nodes measured by SPECT-CT after 99mTc-nanocolloid injection around the primary tumor. All these phase II trials indicate that the recurrence rate outside the radiation field is low (up to 4%). Most recurrences occur in high-risk regions of the clinical target volume (CTV) and in distant regions. However, results of phase III trials are still pending.

Conclusion: Reducing or even omitting ENI in patients with HNSCC seems to be a promising approach to de-escalation, but results of phase III trials are still pending.

Background: Artificial intelligence (AI)-based autocontouring software has the potential to revolutionize radiotherapy planning. In recent years, several AI-based autocontouring solutions with many advantages have emerged; however, their clinical use raises several challenges related to implementation, quality assurance, validation, and training. The aim of this study was to investigate the current use of AI-based autocontouring software and the associated expectations and hopes of radiation oncologists and medical physicists in German-speaking countries.

Methods: A digital survey consisting of 24 questions including single-choice, multiple-choice, free-response, and five-point Likert scale rankings was conducted using the online tool umfrageonline.com (enuvo GmbH, Pfäffikon SZ, Switzerland).

Results: A total of 163 participants completed the survey, with approximately two thirds reporting use of AI-based autocontouring software in routine clinical practice. Of the users, 92% found the software helpful in clinical practice. More than 90% reported using AI solutions to contour organs at risk (OARs) in the brain, head and neck, thorax, abdomen, and pelvis. The majority (88.8%) reported time savings in OAR delineation, with approximately 41% estimating savings of 11-20 min per case. However, nearly half of the respondents expressed concern about the potential degradation of resident training in sectional anatomy understanding. Of respondents, 60% would welcome guidelines for implementation and use of AI-based contouring aids from their respective radiation oncology societies. Respondents' free-text comments emphasized the need for careful monitoring and postprocessing of AI-delivered autocontours as well as concerns about overreliance on AI and its impact on the development of young physicians' contouring and planning skills.

Conclusion: Artificial intelligence-based autocontouring software shows promise for integration into radiation oncology workflows, with respondents recognizing its potential for time saving and standardization. However, successful implementation will require ongoing education and curriculum adaptation to ensure AI enhances, rather than replaces, clinical expertise.