Radiation Oncology Research Articles

A student trained convolutional neural network competing with a commercial AI software and experts in organ at risk segmentation

This retrospective, multi-centered study aimed to improve high-quality radiation treatment (RT) planning workflows by training and testing a Convolutional Neural Network (CNN) to perform auto segmentations of organs at risk (OAR) for prostate cancer (PCa) patients, specifically the bladder and rectum. The objective of this project was to develop a clinically applicable and robust artificial intelligence (AI) system to assist radiation oncologists in OAR segmentation. The CNN was trained using manual contours in CT-datasets from diagnostic 68Ga-PSMA-PET/CTs by a student, then validated (n = 30, PET/CTs) and tested (n = 16, planning CTs). Further segmentations were generated by a commercial artificial intelligence (cAI) software. The ground truth were manual contours from expert radiation oncologists. The performance was evaluated using the Dice-Sørensen Coefficient (DSC), visual analysis and a Turing test. The CNN yielded excellent results in both cohorts and OARs with a DSCmedian > 0.87, the cAI resulted in a DSC > 0.78. In the visual assessment, 67% (bladder) and 75% (rectum) of the segmentations were rated as acceptable for treatment planning. With a misclassification rate of 45.5% (bladder) and 51.1% (rectum), the CNN passed the Turing test. The metrics, visual assessment and the Turing test confirmed the clinical applicability and therefore the support in clinical routine.

Prostate MRI: bridging radiology and radiation oncology for precision radiation therapy

Prostate MRI: bridging radiology and radiation oncology for precision radiation therapy

Impact of Surgeon-Radiation Oncology Dyads in Oral Cavity Cancer Outcomes.

Multidisciplinary care is paramount in patient-specific decision making, especially as pertaining to oral cavity squamous cell cancer (OCSCC) treatment. Protracted surgery-postoperative-radiation (S-PORT) has a detrimental impact on OCSCC patients' outcomes. This study examined the impact of surgeon-radiation oncologist dyads on the treatment of OCSCC, focusing on S-PORT interval and disease specific outcomes. All OCSCC patients treated in a tertiary cancer center between 2009 to 2017 were included. Patients were categorized into "dyad" and "nondyad" groups defined as whether they were treated by a paired surgeon-radiation oncology team with joint multidisciplinary clinic or shared >30% patient volumes. Univariate and multivariate logistic regression were performed to identify factors associated with a prolonged S-PORT time interval (≥8 weeks). Overall survival and locoregional recurrence were estimated and compared. A total of 444 OCSCC were eligible. Treatment by a dyad was significantly less likely associated with S-PORT ≥ 8 weeks (odds ratio [OR]unadjusted: 0.65; 95% confidence interval [CI] 0.44-0.96; p = 0.03). Obtaining pre-operative radiation oncology consultation also decreased the S-PORT interval. Advanced T-category and the need for free tissue flap reconstruction increased the likelihood of prolonged S-PORT on univariate but not multivariate analysis. No significant differences were observed in overall survival or locoregional recurrence by dyad status nor S-PORT (p > 0.05). Surgeon-radiation oncology dyads significantly minimized time from surgery to postoperative radiation in OCSCC. While improvement in overall survival or locoregional recurrence was not observed, these findings support close knit collaborative multidisciplinary treatment care models, including dyad-based care.

Stereotactic Radiosurgery Dose Reduction for Melanoma Brain Metastases Patients on Immunotherapy or Target Therapy: A Single-Center Experience.

Better local control but higher rates of adverse radiation events (ARE) have been reported when combining American Society for Radiation Oncology (ASTRO)-guideline-suggested dose (SD) stereotactic radiosurgery (SRS) with immunotherapy or targeted therapy for melanoma brain metastases. The objective of this study is to explore the efficacy and safety of lower prescription doses compared with ASTRO guidelines for single-fraction SRS for patients with melanoma metastases who are concurrently receiving immunotherapy or targeted therapy. We conducted a retrospective, single-center study on 194 patients who underwent SRS between 2009 and 2022. After propensity score matching, 71 patients with 292 metastases were included in the ASTRO-SD (20-24 Gy for <2 cm, 18 Gy for ≥2 to <3 cm) group and 33 patients with 292 metastases in the reduced dose (RD, <20 Gy for <2 cm, <18 Gy for ≥2 to <3 cm) group. The median diameter (5.4 vs 5.2 mm, P = .6), prescription volume (0.2 vs 0.2 cm3, P = .2), and radiographic follow-up (11 vs 12 months, P = .2) were similar in the 2 groups. The cumulative incidence of progressing metastases was significantly higher in the SD compared with the RD group (P = .018). Higher prescription volumes and ASTRO-suggested radiation doses were associated with local progression in multivariable analysis. Radiographic AREs were significantly more common in the SD compared with the RD group (8.6% vs 3.1%, P = .005). BRAF and other tyrosine kinase inhibitors' concurrent use, higher prescription volumes, and ASTRO-suggested radiation doses were associated with an increased risk of radiographic ARE. This study provides evidence that RD SRS could offer reduced toxicity rates, while maintaining high local control as compared with the current guideline-SDs for the treatment of melanoma brain metastases.

The Impact of Standardized Training Resident on Pain Management in Patients with Advanced Lung Cancer.

This study aimed to investigate the effects of Standardized Training Resident on pharmacological interventions for pain management in patients with advanced lung cancer. A total of 84 patients with advanced lung cancer and associated pain were enrolled in the study from December 2019 to August 2023 and were divided into two groups based on their attending physician: a group managed by physician-ST Training Physicians (joint group) (n = 42) and physician-only group (usual group) (n = 42). The Brief Pain Inventory (BPI), oral morphine equivalent, and length of hospital stay. Furthermore, the Pain Management Index (PMI) was calculated. Health-related quality of life (HRQoL) was assessed at the 4-week follow-up using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). At week 4, compared to the usual group, the four BPI pain intensity categories were significantly lower in the joint group [worst pain: 4 (3-5) vs 8 (7-9); least pain: 1 (0-2) vs 3 (1-4); average pain: 2 (1-2) vs 5 (4-6); pain right now: 1.2 (0.7-1.9) vs 4 (3-5)] (all P > 0.05). The hospital stay duration was significantly reduced; for the seven pain interference categories, there were no significant improvements in the joint group. Significantly more patients achieved adequate pain control in the joint group than the usual group (p = .002). A reduction in OMEDD scores was observed for both cohorts, and the joint group's reduction was statistically more significant (p = 0.016). There were no significant differences in HRQoL between the two groups. Standardized Training for Radiation Oncology Physicians may lead to improved pharmacological interventions and enhanced pain relief. Recognizing the importance of these trainees in the healthcare team is crucial for achieving optimal pain management outcomes.

A Case Report and Literature Review of Metastatic Small Cell Carcinoma in Parotid Gland

Small cell lung cancer usually presents as a progressive disease in over 70% of patients. Common organs of metastasis include the liver, adrenal glands, bones, and brain. However, metastasis to the parotid gland is uncommon, as it has been discussed only in case reports. Among all parotid tumors, small cell cancer is rare, seen in only 1.7%.A 60-year-old man presented with a slow-growing, painless tumor of the left parotid gland and peripheral facial paralysis. Neck ultrasound identified a solid mass in the left parotid gland with enlarged lymph nodes in the parotid gland and ipsilateral neck lymphadenopathies with pathologic features in levels 2 and 3. Chest computed tomography (CT) demonstrated subsegmental collapse in the lingula with peribronchial cuffing in this lobe and mild cylindrical bronchiectatic changes in the left lower lobe. CT also showed multiple mediastinal lymphadenopa thies in prevascular, paraaortic, and paratracheal spaces. Core needle biopsy was done, and initial analysis revealed small cell carcinoma in the left parotid gland. Immunohistochemical analysis of the specimen demonstrated and confirmed the diagnosis. The patient was then referred to the radiation oncology unit for treatment. Chemotherapy was initiated with a combination of cisplatin and etoposide. No complications of the chemotherapy were observed after three cycles; treatment and follow-up are ongoing. No irradiation was performed after evaluation by the radiation oncology department. Due to the advanced stage of his disease, treatment is set for palliative purposes only. Small cell lung cancer diagnosed from solitary metastasis to the parotid gland is very rare. Physicians should keep pulmonary origin in mind when faced with a parotid tumor, as without careful examination, the primary focus may be overlooked, negatively impacting survival rates and the prognosis of the patient. Overall, this finding carries a poor prognosis, but the mainstay of treatment is palliation with systemic chemotherapy and possibly irradiation to control symptoms

Interobserver variability of clinical target volume delineation in patients undergoing breast-conserving surgery without surgical clips: a pilot study on preoperative magnetic resonance simulation

BackgroundIn patients undergoing breast-conserving therapy without surgical clip implantation, the accuracy of tumor bed identification and the consistency of clinical target volume (CTV) delineation under computed tomography (CT) simulation remain suboptimal. This study aimed to investigate the feasibility of implementing preoperative magnetic resonance (MR) simulation on delineations by assessing interobserver variability (IOV).MethodsPreoperative MR and postoperative CT simulations were performed in patients who underwent breast-conserving surgery with no surgical clips implanted. Custom immobilization pads were used to ensure the same supine position. Three radiation oncologists independently delineated the CTV of tumor bed on the images acquired from MR and CT simulation registration and CT simulation alone. Cavity visualization score (CVS) was assigned to each patient based on the clarity of the tumor bed on CT simulation images. IOV was indicated by generalized conformity index (CIgen), denoted as CIgen−CT and CIgen−MR/CT, and the distance between the centroid of mass (dCOM), denoted as dCOMCT and dCOMMR/CT. The variation of IOV in different CVS subgroups was analyzed.ResultsA total of 10 patients were enrolled in this study. The median and interquartile range (IQR) of maximum pathological diameter of the tumors in all patients were 1.55 (0.80–1.92) cm. No statistical significance was found between the volumes of CTVs on CT simulation and on MR/CT simulation registration images (p = 0.387). CIgen−MR/CT was significantly larger than CIgen−CT (p = 0.005). dCOMMR/CT was significantly smaller than dCOMCT (p = 0.037). The median and IQR of CVS in all patients were 2.34 (2.00–3.08). The difference of CIgen between CIgen−MR/CT and CIgen−CT was larger in the low CVS group (p = 0.016). The difference of dCOM showed a decreasing trend when CVS was lower, although it did not reach statistical significance (p = 0.095).ConclusionsFor patients who underwent breast-conserving surgery without surgical clip implantation, the use of preoperative MR simulation in delineating the CTV of tumor bed decreased the IOV among observers. The consistency of tumor bed identification was improved especially in cases where the margins of tumor bed were challenging to visualize on CT simulation images. The study findings offer potential benefits in reducing local recurrence and minimizing tissue irritation in the surrounding areas. Future investigation in a larger patient cohort to validate our results is warranted.

219 HEROCARE: Holistic Empowerment in Radiation Oncology for Cancer Children and Carers

219 HEROCARE: Holistic Empowerment in Radiation Oncology for Cancer Children and Carers

MSOR08 Presentation Time: 8:35 AM: Confidence in Brachytherapy Proficiency among Graduating Radiation Oncology Residents between 2020-2023

MSOR08 Presentation Time: 8:35 AM: Confidence in Brachytherapy Proficiency among Graduating Radiation Oncology Residents between 2020-2023

Second Look Opportunity for Radiation Oncology Medical Residency During Virtual Interview Season

PurposeDespite easing of COVID-19 travel restrictions and social distancing, medical radiation oncology (RO) residency interviews for the 2023 Match remained exclusively virtual. Virtual interviews can be limited in providing program atmosphere, resident camaraderie, and city culture. Our institution offered a voluntary in-person second look (SL) to address these concerns and supplement the virtual interview. Methods and MaterialA voluntary in-person SL across 3 dates was offered to all applicants who successfully interviewed with the RO department for the 2023 Match (n=54). Attendees of the SLs (n=38) were invited to complete a voluntary 10-question anonymous survey after Match Day regarding their perspectives on this opportunity including motivations for attending, financial burden, and perceived benefits of SLs. Results38 individuals (70%) attended one of the departmental SLs with 19 participants (50%) completing the survey. 16 out of 19 (84%) participants traveled >200 miles to attend. All surveyed applicants were grateful for the in-person SL opportunity and agreed such opportunities should continually be offered with exclusively virtual residency interviews. All participants reported that their decision to attend the SL was affected by departmental financial support. Two applicants felt pressured to attend the SL to remain competitive to the program. Majority of applicants agreed that they achieved a better “feel” for the program culture and the larger institution, resident camaraderie, and the surrounding city from this in-person SL encounter, compared to virtual interview alone (18, 94%). ConclusionThese in-person second look opportunities were well-attended, well-received, and offered insights and experiences to RO resident applicants in the setting of exclusively virtual interviews. The cost of attendance may be a limiting factor when applicants are deciding to attend in-person SLs. Caution is needed to ensure applicants do not feel obligated to attend and SLs are not used as a platform for inappropriate post interview communication.

Mitigating Interobserver Variability in Radiomics with ComBat: A Feasibility Study

This study investigates Intraobserver Features Variability (IFV) in radiomics studies and assesses the effectiveness of the ComBat harmonization method in mitigating these effects. Methods: This study utilizes data from the NSCLC-Radiomics-Interobserver1 dataset, comprising CT scans of 22 Non-Small Cell Lung Cancer (NSCLC) patients, with multiple Gross Tumor Volume (GTV) delineations performed by five radiation oncologists. Segmentation was completed manually (“vis”) or by autosegmentation with manual editing (“auto”). A total of 1229 radiomic features were extracted from each GTV, segmentation method, and oncologist. Features extracted included first order, shape, GLCM, GLRLM, GLSZM, and GLDM from original, wavelet-filtered, and LoG-filtered images. Results: Before implementing ComBat harmonization, 83% of features exhibited p-values below 0.05 in the “vis” approach; this percentage decreased to 34% post-harmonization. Similarly, for the “auto” approach, 75% of features demonstrated statistical significance prior to ComBat, but this figure declined to 33% after its application. Among a subset of three expert radiation oncologists, percentages changed from 77% to 25% for “vis” contouring and from 64% to 23% for “auto” contouring. This study demonstrates that ComBat harmonization could effectively reduce IFV, enhancing the feasibility of multicenter radiomics studies. It also highlights the significant impact of physician experience on radiomics analysis outcomes.

Optimización de la triple terapia en el tratamiento del cáncer de próstata hormonosensible metastásico

Triple therapy with docetaxel, androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPIs) has demonstrated survival benefits in patients with metastatic hormone-sensitive prostate cancer (mHSPC), especially in those with high-risk disease. However, once the use of ADT and docetaxel is established, guidelines do not clearly specify which ARPI is most appropriate. In this work, a literature review to identify phase III clinical trials, systematic reviews, meta-analyses, and clinical practice guidelines on triple therapy in mHSPC was carried out. Evidence and recommendations were qualitatively reviewed to provide guidelines on the most suitable ARPI based on patient risk, disease volume, and nature of metastases (synchronous or metachronous). This review aims to update the previously published consensus on the optimal pharmacological treatment for mHSPC and to expose the opinions of hospital pharmacy, urology and medical and radiation oncology experts.

Benign and malignant breast lesions in children and adolescents - diagnostic and therapeutic approach.

Benign and malignant breast lesions in children and adolescents are rare compared to adults. Most tumors are benign. Malignant breast lesions are extremely rare. Fibroadenomas are the most common, accounting for 95% of all lesions. Diagnosis is based on history and physical examination of the breast and armpit. Imaging studies include ultrasound, mammography, and magnetic resonance imaging. Ultrasound is the most commonly used imaging test. Other tests are used in cases of diagnostic doubt. Core needle biopsy should be considered for appropriate diagnostic management. Excisional biopsy should be considered for complex clinical conditions and imaging studies. Except in doubtful situations in children and adolescent girls, a conservative approach and observation of the lesions along with periodic ultrasound examination initially every 6-12 months is advisable. Management of malignant breast lesions in children typically involves a multidisciplinary team consisting of pediatric oncologists, surgeons, radiation oncologists, pathologists, and other specialists and depends on the clinical condition of the patient. An important aspect is the experience of the clinician and radiologist in the treatment of breast lesions, as well as increasing patient and family awareness of possible breast lesions and self-examination. This review aims to provide a scoping overview of the available literature on benign and malignant lesions of the breast in pediatric and adolescent populations to assist physicians and surgeons in making decisions regarding the appropriate diagnosis and management of pediatric breast disease.

Circulating DNA in Rectal Cancer to Unravel the Prognostic Potential for Radiation Oncologist: A Meta-analysis.

Liquid biopsy, with its noninvasive nature and ability to detect tumor-specific genetic alterations, emerges as an ideal biomarker for monitoring recurrences for locally advanced rectal cancer (LARC). Completed studies have small sample sizes and different experimental methods. To consolidate and assess the collective evidence regarding the prognostic role of circulating DNA (ctDNA) detection in LARC patients undergoing neoadjuvant chemoradiotherapy (nCRT). Computerized bibliographic searches of MEDLINE and CANCERLIT (2000 to 2023) were supplemented with hand searches of reference lists. Study selection: studies evaluating oncological outcomes of patients with LARC treated with a nCRT comparing patients with positive and negative liquid biopsy at baseline and after nCRT. Data extraction: data on population, intervention, and outcomes were extracted from each study, in accordance with the intention to treat method, by 2 independent observers, and combined using the DerSimonian method and Laird method. Nine studies follow inclusion criteria including 678 patients treated with nCRT. The pooled RD rate of ctDNA negative between measure at baseline and after nCRT is statistically significant 61% (95% CI: 53-70, P=0.0002). The hazard ratio (HR) of progression-free survival between ct-DNA negative and positive is significant 7.41 (95% CI: 4.87-11.289, P<0.00001). ctDNA can identify patients with different recurrence risks following nCRT and assess prognosis in patients with LARC. Further prospective study is necessary to determine the utility of ctDNA in personalised therapy for patients with LARC.

Artificial intelligence-assisted delineation for postoperative radiotherapy in patients with lung cancer: a prospective, multi-center, cohort study

BackgroundPostoperative radiotherapy (PORT) is an important treatment for lung cancer patients with poor prognostic features, but accurate delineation of the clinical target volume (CTV) and organs at risk (OARs) is challenging and time-consuming. Recently, deep learning-based artificial intelligent (AI) algorithms have shown promise in automating this process.ObjectiveTo evaluate the clinical utility of a deep learning-based auto-segmentation model for AI-assisted delineating CTV and OARs in patients undergoing PORT, and to compare its accuracy and efficiency with manual delineation by radiation oncology residents from different levels of medical institutions.MethodsWe previously developed an AI auto-segmentation model in 664 patients and validated its contouring performance in 149 patients. In this multi-center, validation trial, we prospectively involved 55 patients and compared the accuracy and efficiency of 3 contouring methods: (i) unmodified AI auto-segmentation, (ii) fully manual delineation by junior radiation oncology residents from different medical centers, and (iii) manual modifications based on AI segmentation model (AI-assisted delineation). The ground truth of CTV and OARs was delineated by 3 senior radiation oncologists. Contouring accuracy was evaluated by Dice similarity coefficient (DSC), Hausdorff distance (HD), and mean distance of agreement (MDA). Inter-observer consistency was assessed by volume and coefficient of variation (CV).ResultsAI-assisted delineation achieved significantly higher accuracy compared to unmodified AI auto-contouring and fully manual delineation by radiation oncologists, with median HD, MDA, and DCS values of 20.03 vs. 21.55 mm, 2.57 vs. 3.06 mm, 0.745 vs. 0.703 (all P&amp;lt;0.05) for CTV, respectively. The results of OARs contours were similar. CV for OARs was reduced by approximately 50%. In addition to better contouring accuracy, the AI-assisted delineation significantly decreased the consuming time and improved the efficiency.ConclusionAI-assisted CTV and OARs delineation for PORT significantly improves the accuracy and efficiency in the real-world setting, compared with pure AI auto-segmentation or fully manual delineation by junior oncologists. AI-assisted approach has promising clinical potential to enhance the quality of radiotherapy planning and further improve treatment outcomes of patients with lung cancer.

German radiation oncology's next generation: a web-based survey of young biologists, medical physicists, and physicians-from problems to solutions.

Radiation science is of utmost significance not only due to its growing importance for clinical use, but also in everyday life such as in radiation protection questions. The expected increase in cancer incidence due to an aging population combined with technical advancements further implicates this importance and results in ahigher need for sufficient highly educated and motivated personnel. Thus, factors preventing young scientists and medical personnel from entering or remaining in the field need to be identified. Aweb-based questionnaire with one general and three occupation-specific questionnaires for physicians, biologists, and medical physicists working in radiation oncology and research was developed and circulated for 6weeks. While the overall satisfaction of the 218 participants was quite high, there are some points that still need to be addressed in order to ensure acontinuing supply of qualified personnel. Among these were economic pressure, work-life balance, work contracts, protected research time, and ademand for an improved curriculum. Mentoring programs, improved education, and strengthening the value of societies in radiation sciences as well as translational approaches and more flexible working arrangements might ensure ahigh-quality workforce and thus patient care in the future.

Prognostic Impact of Low Muscle Mass and Inflammatory Markers in Stage III Nonsmall Cell Lung Cancer Turkish Oncology Group and Turkish Society of Radiation Oncology Thoracic Cancer Study Group (08-005).

The aim of this retrospective multicenter study was to evaluate the prognostic significance of low muscle mass, and inflammatory markers in patients with stage III nonsmall cell lung cancer (NSCLC) who received definitive chemoradiotherapy (CRT). Furthermore, the study aimed to determine the threshold value of disease-specific low muscle mass. A total of 461 patients with stage III NSCLC were evaluated. Low muscle mass, prognostic nutritional index (PNI), and biochemical inflammatory markers were assessed. The Kaplan-Meier method and Cox regression analysis were used to analyze overall survival (OS) and progression-free survival (PFS). This study found a disease-specific low muscle mass threshold of LSMI <38.7cm²/m² for women and <45.1cm²/m² for men, with 25.2% of patients having disease-specific low muscle mass. Multivariate cox regression analysis revealed that low PNI was found to be an independent unfavorable prognostic factor for both PFS (HR=0.67; 95% CI: 0.48-0.92, P= 0.015) and OS (HR=0.67; 95% CI: 0.50-0.91, P=0.008). Other factors including ECOG PS 3 (HR=7.76; 95% CI: 1.73-34.76, P=0.007), induction CT (HR=0.66; 95% CI: 0.49-0.88, P= 0.004), and disease-specific low muscle mass (HR=1.40; 95% CI: 1.02-1.92, P= 0.038) also had independent effects on prognosis. The present study provides evidence that the presence of low muscle mass and low PNI significantly impacts the prognosis of patients with stage III NSCLC who undergo definitive CRT. Furthermore, our study is notable for being the first multicenter investigation to identify a disease-specific low muscle mass threshold.

Introduction of an Educational Video to Enhance the Informed Consent Process in Postoperative Radiation Therapy of Breast Cancer Patients.

Informed consent is crucial in medical practice, especially for complex treatments such as postoperative radiotherapy for patients with breast cancer. Conventional consent procedures are often based on verbal declarations with a highly condensed but nevertheless large amount of information, which can exceed the recording capacity of patients and lead to misunderstandings. The aim of this study was to develop and test an educational video on breast cancer patients to enhance the informed consent process by improving patients' understanding and reducing the duration of the subsequent consultation. The educational video was created after the underlying content was determined by a modified Delphi method in which a panellist of radiation oncologists, nurses, radiation therapists, and former patients participated in successive rounds of topic scoring. After achieving content consent, the video included 19 items to cover key aspects of postoperative radiotherapy in a patient-friendly manner. Fifty breast cancer patients scheduled for postoperative radiotherapy were randomised to watch the video prior to their verbal consultation (n = 25) or to the control group participating in the traditional informed consent process only (n = 25). The duration of the informed consent processes in both arms was recorded. To assess the educational effect of the video, a multiple-choice test was created. In addition, patients' satisfaction was recorded using a separate questionnaire. Both questionnaires were completed by the patients one to two hours after signing the consent form. The patients in the video group evidenced significantly higher knowledge scores than those who received standard verbal explanations (median number of correct answers 9 vs. 8 out of 10, p = 0.0039). The whole informed consent process was also completed faster in the video group (mean duration 34.7 vs. 46.2 min, p < 0.001). Median satisfaction scores were high in both groups (34 vs. 33 out of 35 points), with no significant differences observed (p > 0.05). The educational video effectively improved patient understanding and streamlined the informed consent process without compromising patients' satisfaction. This approach also helps to standardise the delivery of complex medical information, and it can also be adapted to improve the informed consent process for other cancer treatments.

Assessing the practice of total neoadjuvant therapy for rectal cancer: an online survey among radiation oncology departments in Germany and German-speaking regions of Austria and Switzerland.

Total neoadjuvant therapy (TNT) of rectal cancer improves rates of pathological complete remission and progression-free survival. With improved clinical response rates, interest grew in a non-operative approach/watch and wait (WaW) for this disease. In 2020, the working groups of ACO/AIO/ARO published a consensus statement on the use of TNT, including a non-operative approach. However, the best combination scheme remains unclear. Despite the increasing use of TNT, there is a lack of comprehensive data on its current implementation and practices. To address this knowledge gap, a multicenter survey was conducted to capture the use of TNT protocols in German-speaking radiotherapy departments. At the beginning of 2023, a GDPR-compliant online survey was conducted in Germany, Austria, and German-speaking Switzerland. The questionnaire comprised 43 questions covering various aspects of TNT, including chemotherapy and WaW concepts. Most respondents (98.4%) confirmed awareness of the consensus on TNT for rectal cancer. Institutions treated an average of 30.22 rectal cancer patients annually. Most respondents (76.2%) reported treating over 80% of patients neoadjuvantly. Regarding TNT, 33.3% treated 21-50% with such a protocol. No significant association was found between the institution type and TNT application. In 62/63 cases, tumor board discussion was standard before offering TNT. VMAT was the predominant technique (82.5%). For rectal cancer dosing, the 50/50.4Gy scheme was most common, followed by 45Gy with a boost and the 5 × 5Gy scheme. Dosing schemes for TNT varied slightly, with more participants reporting the use of 5 × 5Gy compared to radiation therapy for rectal cancer in general. CBCT was the primary IGRT method (88.9%). Larger hospitals typically administered chemotherapy themselves, while private practices collaborated with medical oncologists (p < 0.0001). The most common concurrent chemotherapy drugs were 5-fluorouracil/capecitabine (64.4%) and oxaliplatin (37.3%). A WaW strategy was reported to be institutional implemented by 63.8%. The timing of offering WaW was split, with 50% offering it after radiochemotherapy and 47% during the informed consent talk. For planned WaW, 62% prefer normofractionated TNT. TNT appears to be widely implemented in the German-speaking radio-oncological community, regardless of the type of institution. Image-guided therapy, multidisciplinary team decisions, and internal guidelines play an important role. TNT seems to have already altered treatment protocols for rectal cancer toward an organ-preserving approach in selected cases. In these WaW cases, normofractionation appears to be preferred over hypofractionation.

High-throughput, low-cost FLASH: irradiation of Drosophila melanogaster with low-energy X-rays using time structures spanning conventional and ultrahigh dose rates.

FLASH radiotherapy is an emerging technique in radiation oncology that may improve clinical outcomes by reducing normal tissue toxicities. The physical radiation characteristics needed to induce the radiobiological benefits of FLASH are still an active area of investigation. To determine the dose rate, range of doses and delivery time structure necessary to trigger the FLASH effect, Drosophila melanogaster were exposed to ultrahigh dose rate (UHDR) or conventional radiotherapy dose rate (CONV) 120-kVp X-rays. A conventional X-ray tube outfitted with a shutter system was used to deliver 17- to 44-Gy doses to third-instar D. melanogaster larvae at both UHDR (210Gy/s) and CONV (0.2-0.4Gy/s) dose rates. The larvae were then tracked through development to adulthood and scored for eclosion and lifespan. Larvae exposed to UHDR eclosed at higher rates and had longer median survival as adults compared to those treated with CONV at the same doses. Eclosion rates at 24Gy were 68% higher for the UHDR group (P<0.05). Median survival from 22Gy was >22days for UHDR and 17days for CONV (P<0.01). Two normal tissue-sparing effects were observed for D. melanogaster irradiated with UHDR 120-kVp X-rays. The effects appeared only at intermediate doses and may be useful in establishing the dose range over which the benefits of FLASH can be obtained. This work also demonstrates the usefulness of a high-throughput fruit fly model and a low-cost X-ray tube system for radiobiological FLASH research.