Strahlentherapie und Onkologie最新文献

Breast cancer is the most frequent type of cancer in women, with significant incidence and fatality rates. Radiation therapy is an important therapeutic option for breast cancer patients. However, tumor cells' resistance to radiation can limit therapy efficacy, resulting in recurrence and death. Non-coding RNAs (ncRNAs) are a class of small RNA molecules that do not translate into proteins but can affect the translation of target mRNA. Several investigations on breast cancer have demonstrated abnormal expression of ncRNAs in response to radiation. Non-coding RNAs are essential in controlling numerous processes such as DNA damage response, cancer stem cell pathways, cell cycle regulation, cell death, and inflammation. Dysregulation of ncRNAs after irradiation influences radiosensitivity or radioresistance of breast cancer cells. Understanding the molecular mechanisms underlying Radiation response can lead to innovative treatment ways to reduce breast cancer radioresistance and increase radiotherapy's efficacy. This review summarizes current research on ncRNA dysregulation following irradiation and analyzes ncRNAs' function and mechanism in modifying breast cancer cell radiosensitivity and radioresistance.

Purpose: The appearance of symptomatic tumor-related vaginal bleeding and pain in advanced incurable cancer patients with pelvic gynecological malignancies remains a therapeutic challenge in oncological treatment. The aim of our analysis was to evaluate the efficacy and safety of palliative hemostatic radiotherapy.

Methods: We retrospectively identified patients who had received palliative hemostatic radiotherapy (RT) at our institution between 2011 and 2023 and evaluated acute toxicity, local control, cessation of bleeding, and pain relief.

Results: In total, 40 patients with a median planning target volume of 804 cm³ were treated with a median total dose of 39 Gy in 13 fractions, resulting in 6‑month and 1‑year local control rates of 66.9 and 60.8%, respectively. No higher-grade (>grade III) acute RT-induced toxicity appeared. Complete cessation of bleeding was achieved in 80.0% of all patients after a median of 16 days and pain relief was documented in 60.9% at first follow-up. 37.5% of the women required a blood transfusion and 25% an additional tamponade with local hemostatic agents. Successful stopping of bleeding was significantly less frequent in patients receiving anticoagulation concurrently with radiation and in the case of infield re-irradiation. Patients with a higher total RT dose had cessation of bleeding significantly more often, with a cut-off value of at least EQD2 (α/β = 10) = 36 Gy. The applied RT technique and planning target volume had no significant influence on the occurrence of bleeding cessation.

Conclusion: Palliative hemostatic radiotherapy for locally advanced pelvic gynecological malignancies is safe and effective in achieving high control rates of hemostasis in tumor bleeding and pain relief.

Background: Promptable foundation auto-segmentation models like Segment Anything (SA, Meta AI, New York, USA) represent a novel class of universal deep learning auto-segmentation models that could be employed for interactive tumor auto-contouring in RT treatment planning.

Methods: Segment Anything was evaluated in an interactive point-to-mask auto-segmentation task for glioma brain tumor auto-contouring in 16,744 transverse slices from 369 MRI datasets (BraTS 2020 dataset). Up to nine interactive point prompts were automatically placed per slice. Tumor boundaries were auto-segmented on contrast-enhanced T1w sequences. Out of the three auto-contours predicted by SA, accuracy was evaluated for the contour with the highest calculated IoU (Intersection over Union, "oracle mask," simulating interactive model use with selection of the best tumor contour) and for the tumor contour with the highest model confidence ("suggested mask").

Results: Mean best IoU (mbIoU) using the best predicted tumor contour (oracle mask) in full MRI slices was 0.762 (IQR 0.713-0.917). The best 2D mask was achieved after a mean of 6.6 interactive point prompts (IQR 5-9). Segmentation accuracy was significantly better for high- compared to low-grade glioma cases (mbIoU 0.789 vs. 0.668). Accuracy was worse using the suggested mask (0.572). Stacking best tumor segmentations from transverse MRI slices, mean 3D Dice score for tumor auto-contouring was 0.872, which was improved to 0.919 by combining axial, sagittal, and coronal contours.

Conclusion: The Segment Anything foundation segmentation model can achieve high accuracy for glioma brain tumor segmentation in MRI datasets. The results suggest that foundation segmentation models could facilitate RT treatment planning when properly integrated in a clinical application.

Purpose: Conventional image-guided radiotherapy (IGRT) of the prostate bed is challenged by the varying anatomy due to dynamic changes of surrounding organs such as the bladder and rectum. This leads to changed dose coverage of target and surrounding tissue. The novel online adaptive radiotherapy (oART) aims to improve target coverage as well as reduce dose exposure to surrounding healthy tissues by daily reoptimization of treatment plans. Here we set out to quantify the resulting changes of this adaptation for patients and treatment team.

Methods: A total of 198 fractions of radiotherapy of the prostate bed (6 patients) were treated using oART with the Ethos accelerator (Varian Medical Systems, Palo Alto, CA, USA). For each fraction, volumes and several dose-volume parameters of target volumes and organs at risk were recorded for the scheduled plan (initial plan, recalculated based on daily cone beam computed tomography [CBCT]), the adapted plan, and the verification plan, which is the dose distribution of the applied plan recalculated on the closing CBCT after the adaptation process. Clinical acceptability for all plans was determined using given dose-volume parameters of target volumes. Additionally, the time needed for the adaptation process was registered and compared to the time required for the daily treatment of five conventional IGRT patients.

Results: Volumes of target and organs at risk (OAR) exhibited broad variation from day to day. The differences in dose coverage D_98% of the clinical target volume (CTV) were significant through adaptation (p < 0.0001; median D_98% 97.1-98.0%) and further after verification CBCT (p < 0.001; median D_98% 98.1%). Similarly, differences in D_98% of the planning target volume (PTV) were significant with adaptation (p < 0.0001; median D_98% 91.8-96.5%) and after verification CBCT (p < 0.001; median D_98% 96.4%) with decreasing interquartile ranges (IQR). Dose to OAR varied extensively and did not show a consistent benefit from oART but decreased in IQR. Clinical acceptability increased significantly from 19.2% for scheduled plans to 76.8% for adapted plans and decreased to 70.7% for verification plans. The scheduled plan was never chosen for treatment. The median time needed for oART was 25 min compared to 8 min for IGRT.

Conclusion: Target dose coverage was significantly improved using oART. IQR decreased for target coverage as well as OAR doses indicating higher repeatability of dose delivery using oART. Differences in doses after verification CBCT for targets as well as OAR were significant compared to adapted plans but did not offset the overall dosimetric gain of oART. The median time required is three times higher for oART compared to IGRT.

Background: The use of positron-emission tomography (PET)/computed tomography (CT) in radiation therapy (RT) has increased. Radiation oncologists (RadOncs) have access to PET/CT with a variety of tracers for different tumor entities and use it for target volume definition. The German Society of Nuclear Medicine (DGN) and the German Society of Radiation Oncology (DEGRO) aimed to identify current patterns of care in order to improve interdisciplinary collaboration.

Methods: We created an online survey on participating RadOncs' use of PET tracers for different tumor entities and how they affect RT indication, dose prescription, and target volume definition. Further topics were reimbursement of PET/CT and organizational information (fixed timeslots and use of PET with an immobilization device [planning/RT-PET]). The survey contained 31 questions in German language (yes/no questions, multiple choice [MC] questions, multiple select [MS] questions, and free-text entry options). The survey was distributed twice via the DEGRO member mailing list.

Results: During the survey period (May 22-August 7, 2023) a total of 156 RadOncs (13% of respondents) answered the survey. Among these, 59% reported access to diagnostic PET/CT within their organization/clinic and 24% have fixed timeslots for their patients. 37% of survey participants can perform RT-PET and 29% have the option of providing a dedicated RT technician for planning PET. Besides [¹⁸F]-fluorodeoxyglucose (FDG; mainly used in lung cancer: 95%), diagnostic prostate-specific membrane antigen (PSMA)-PET/CT for RT of prostate cancer is routinely used by 44% of participants (by 64% in salvage RT). Use of amino acid PET in brain tumors and somatostatin receptor PET in meningioma is low (19 and 25%, respectively). Scans are reimbursed through private (75%) or compulsory (55%) health insurance or as part of indications approved by the German Joint Federal Committee (Gemeinsamer Bundesausschuss; 59%). 98% of RadOncs agree that PET impacts target volume definition and 62% think that it impacts RT dose prescription.

Discussion: This is the first nationwide survey on the role of PET/CT for RT planning among RadOncs in Germany. We find high acceptance of PET results for treatment decisions and target volume definition. Planning PET comes with logistic challenges for different healthcare settings (e.g., private practices vs. university hospitals). The decision to request PET/CT is often based on the possibility of reimbursement.

Conclusion: PET/CT has become an important tool for RadOncs, with several indications. However, access is still limited at several sites, especially for dedicated RT-PET. This study aims to improve interdisciplinary cooperation and adequate implementation of current guidelines for the treatment of various tumor entities.

Introduction: Bloom syndrome (BS) is a rare autosomal recessive disorder caused by a loss-of-function mutation in the BLM gene encoding an RecQ helicase involved in DNA repair and maintenance of chromosomal stability. In patients with BS, significant sensitivity to both DNA-damaging chemotherapy (CT) and ionizing radiation complicates the management of neoplasms by exacerbating comorbidities and predisposing to toxicities and poor outcomes.

Case report: A 30-year-old female patient diagnosed with BS who presented with early-stage triple-negative breast cancer was treated with four cycles of doxorubicin (60 mg/m²) and cyclophosphamide (600 mg/m²) followed by weekly paclitaxel (80 mg/m²) for 12 weeks as the chemotherapy protocol and a total of 5000 cGy curative radiotherapy (RT). Due to pancytopenia 8 months after completion of therapy, bone marrow biopsy and aspiration were performed, and a diagnosis of myelodysplastic syndrome with excess blasts 2 (MDS-EB2) was made. Two courses of the azacitidine (75 mg/m²) protocol were administered every 28 days in the hematology clinic. Two weeks after CT the patient was transferred from the emergency department to the hematology clinic with the diagnosis of pancytopenia and febrile neutropenia. She died at the age of 33 due to sepsis that developed during follow-up.

Conclusion: Due to the rarity of BS, there is no prospective trial in patients with cancer and no evidence base upon which to design treatment programs. For these reasons, it is strongly recommended that patients receive multidisciplinary care, with precise assessment and discussion of the indication and an adequate dose of DNA-damaging agents such as chemotherapy and ionizing radiation.