Radiotherapy and Oncology最新文献

Background: Data evaluating the impact of intensity-modulated proton therapy (IMPT) on survival among nasopharyngeal carcinoma (NPC) patients are limited. This study aims to elucidate the survival benefits and toxicity profiles of IMPT compared to modern photon therapy, volumetric-modulated arc therapy (VMAT), over an extended follow-up period.

Methods: We analyzed data from NPC patients recorded in the Chang Gung Research Database. This analysis focused on individuals who received definitive radiotherapy, either IMPT or VMAT therapy, from 2016 to 2021. Patients with distant metastasis or concurrent other malignancies were excluded. We performed 1:1 matching based on stage, year of diagnosis, and age (± 10 years). Oncological outcomes and toxicities were assessed using Cox proportional hazards modeling. For sensitivity analysis, we employed inverse probability of treatment weighting and additional 1:2 matching.

Results: Out of a 1,202 NPC patients' cohort, 276 were selected from a subset of 294 who received IMPT and matched with an equivalent number of patients receiving VMAT. IMPT was associated with improved oncological outcomes after matching, with an adjusted hazard ratio (aHR) of 0.31 (95% CI: 0.15-0.62) for all-cause mortality and an aHR of 0.58 (95% CI: 0.34-0.99) for disease recurrence. Additionally, IMPT was linked to a reduced incidence of feeding tube placement, with an aHR of 0.31 (95% CI: 0.18-0.55). Competing risk and sensitivity analyses corroborated these trends, though the significance for disease recurrence was not consistent.

Conclusion: IMPT was associated with significantly better overall survival outcomes and a lower incidence of dysphagia compared to VMAT in NPC patients. Further randomized trials are needed to confirm these findings.

Purpose: This study aims to investigate and compare High Dose Rate Brachytherapy (HDR-BT) with Helical Tomotherapy (HT) treatment plans. The focus is on small target volumes near radiation-sensitive organs in the ocular region, to evaluate the advantages of these techniques in treating skin cancer.

Methods: This retrospective observational analysis included patients who underwent skin cancer HDR-BT Freiburg flap treatment between 2019 and 2023. An expert radiation oncologist contoured the planning target volumes (PTVs) and marked their visible extension with a radio-opaque tin wire. Each patient had two treatment plans: an individually shaped HDR-BT surface mold and an HT calculation used specifically for this study. Quality assurance of treatment plan was performed in both HDR-BT and HT. The plans were then compared using organ at risk (OAR) maximum doses and the conformity index CI. Radiation oncologists assessed their quality using their routine workflow evaluation plan.

Results: Twelve patients were selected for the inclusion in this study. HT provided more consistent target coverage than HDR-BT, with a statistically significant difference (p < 0.05) at t-test. HT showed higher CIs and maximum dose for the optic nerve, optic chiasm, and lens in the homolateral part. Radiation oncologists preferred the overall quality of HT treatment due to its superior PTV coverage, especially for convex surfaces, while maintaining effective OAR sparing. HDR-BT is preferred when concave surfaces are present.

Conclusion: HT offers more conformal treatment, although some OAR parameters are statistically significantly better with HDR-BT, which may also be superior for complex geometries.

Background and purpose: Accurate segmentation of the clinical target volume (CTV) is essential to deliver an effective radiation dose to tumor tissues in cervical cancer radiotherapy. Also, although automated CTV segmentation can reduce oncologists' workload, challenges persist due to the microscopic spread of tumor cells undetectable in CT imaging, low-intensity contrast between organs, and inter-observer variability. This study aims to develop and validate a multi-task feature fusion network (MTF-Net) that uses distance-based information to enhance CTV segmentation accuracy.

Materials and methods: We developed a dual-branch, end-to-end MTF-Net designed to address the challenges in cervical cancer CTV segmentation. The MTF-Net architecture consists of a shared encoder and two parallel decoders, one generating a distance location information map (D_img) and the other producing CTV segmentation masks. To enhance segmentation accuracy, we introduced a distance information attention fusion module that integrates features from the Dimg into the CTV segmentation process, thus optimizing target delineation. The datasets for this study were from three centers. Data from two centers were used for model training and internal validation, and that of the third center was used as an independent dataset for external testing. To benchmark performance, we also compared MTF-Net to commercial segmentation software in a clinical setting.

Results: MTF-Net achieved an average dice score of 84.67% on internal and 77.51% on external testing datasets. Compared with commercial software, MTF-Net demonstrated superior performance across several metrics, including Dice score, positive predictive value, and 95% Hausdorff distance, with the exception of sensitivity.

Conclusions: This study indicates that MTF-Net outperforms existing state-of-the-art segmentation methods and commercial software, demonstrating its potential effectiveness for clinical applications in cervical cancer radiotherapy planning.

Purpose: To retrain a model based on a previously identified prognostic imaging biomarker using apparent diffusion coefficient (ADC) values from diffusion-weighted magnetic resonance imaging (DW-MRI) in a preclinical setting and validate the model using clinical DW-MRI data of patients with locally advanced head-and-neck cancer (HNC) acquired before radiochemotherapy.

Material and methods: A total of 31 HNC patients underwent T2-weighted and DW-MRI using 3 T MRI before radiochemotherapy (35 x 2 Gy). Gross tumor volumes (GTV) were delineated based on T2-weighted and b500 images. A preclinical model previously revealed that the size of high-risk subvolumes (HRS) defined by a band of ADC-values was correlated to radiation resistance. To validate this model, different bands of ADC-values were tested using two-sided thresholds on the low-ADC histogram flank to determine HRSs inside the GTV and correlated to treatment outcome after three years. The best model was used to fit a logistic regression model. Stratification potential regarding outcome was internally validated using bootstrap, receiver-operator-characteristic (ROC)-analysis, Kaplan-Meier- and Cox-method, and compared to GTV, ADC_mean and clinical factors.

Results: The best model was defined by 800-6mm²/s and correlated significantly to treatment outcome (p = 0.003). Optimal HRS cut-off value was found to be 5.8 cm³ according to ROC-analysis. This HRS demonstrated highly significant stratification potential (p < 0.001, bootstrap AUC ≥ 0.84) similar to GTV size (p < 0.001, AUC ≥ 0.79), in contrast to ADC_mean (p = 0.361, AUC = 0.53).

Conclusions: A preclinical prognostic model defined by an ADC-based HRS was successfully retrained and validated in HNC patients treated with radiochemotherapy. After thorough external validation, such functional HRS based on a band of ADC values may in the future allow interventional response-adaptive MRI-guided radiotherapy in online and offline approaches.

Background and purpose: We lack population-based data on the use and effectiveness of phosphodiesterase- 5inhibitors (PDE-5Is) in post-radiotherapy long-term prostate cancer survivors (PCaSs). In this cross-sectional survey performed 9 years after curative radiotherapy we explored PDE-5I use and the drugs'effectiveness in 1,092 nine-year PCaSs responding to the sexual items of EPIC-26. The findings from PCaSs were compared to those from 2,847 age-similar men from the general population (Norms).

Results: 13 % of the PCaSs and 9 % of the Norms were Current Users of PDE-5Ies, High sexual interest and, restricted to PCaSs, age below 70 years significantly increased the use of PDE-Is. In PCaSs and Norms, who used PDE-5Is the levels of the six sexual items of EPIC-26 and of the Sexual Domain Summary Score (DSS) were similar. The corresponding differences were large in Never Users of PDE-5Ies. High sexual interest in PCaSs, and use of PDE-5Is were significantly and positively associated with an acceptable level of the sexual domain in EPIC-26 (Score > 40), whereas the association was negative for age > 70 years, reduced health and obesity, CONCLUSION: At least 1 of 10 long-term post-radiotherapy PCaSs experience "some help" of their erectile dysfunction by use of PDE-5Is. These patients are identified by high sexual interest, age < 70 years and good health During long-term follow-up of PCaSs clinicians are challenged early to identify these, often relatively young men, based on their high sexual interest.