Course Of Radiotherapy Research Articles

Longitudinal assessment of diffusion-weighted imaging during magnetic resonance-guided radiotherapy in head and neck cancer

BackgroundFor radiotherapy of head and neck cancer (HNC) magnetic resonance imaging (MRI) plays a pivotal role due to its high soft tissue contrast. Moreover, it offers the potential to acquire functional information through diffusion weighted imaging (DWI) with the potential to personalize treatment. The aim of this study was to acquire repetitive DWI during the course of online adaptive radiotherapy on an 1.5 T MR-linear accelerator (MR-Linac) for HNC patients and to investigate temporal changes of apparent diffusion coefficient (ADC) values of the tumor and subvolume levels.Methods27 patients treated with curative RT on the 1.5 T MR-Linac with at least weekly DWI in treatment position were included into this prospective analysis and divided in four risk groups (HPV-status and localisation). Tumor and lymph node volumes (GTV-P/GTV-N) were delineated on b = 500 s/mm2 images while ADC maps were calculated using b = 150/200 and 500 s/mm2 images. Absolute and relative temporal changes of mean ADC values, tumor volumes and a high-risk subvolume (HRS) defined by low ADC tumor voxels (600 < ADC < 900 × 10−6 mm2/s) were analyzed. Relative changes of mean ADC values, tumor volumes and HRS were statistically tested using Wilcoxon-signed-rank test.ResultsMedian pretreatment ADC value for all patients resulted in 1167 × 10−6 mm2/s for GTV-P and 1002 × 10−6 mm2/s for GTV-N while absolute pretreatment tumor volume yielded 9.1 cm3 for GTV-P and 6.0 cm3 for GTV-N, respectively. Pretreatment HRS volumes were 1.5 cm3 for GTV-P and 1.3 cm3 for GTV-P and GTV-N. Median ADC values increase during 35 fractions of RT was 49% for GTV-P and 24% for GTV-N during RT. Median tumor volume decrease was 68% and 52% for GTV-P and GTV-N with a median HRS decrease of 93% and 87%. Significant differences from 0 for mean ADC were observed starting from week 1, for tumor volumes from week 2 for GTV-P and week 1 for GTV-N and for HRS in week 1 for GTV-P and week 2 for GTV-N.ConclusionLongitudinal DWI acquisition in HNC is feasible on a MR-Linac during the course of online adaptive MR-guided radiotherapy. Changes in ADC and volumes can be assessed, but future work needs to explore the potential for biologically guided treatment individualization.Trial registration: NCT04172753, actual study start: 09.05.2018.

Digital redesign of the radiotherapy course for medical students with ablended learning approach.

Due to the need for high-quality teaching, we present anew blended learning concept combining digital modules, interactive seminars, and clinical experience. Furthermore, we evaluated its acceptance among students. Anew concept for teaching was applied to the radiotherapy module and made available via the Hannover Medical School (MHH) learning management system as part of ablended learning concept with educational films, multimedia learning modules, online seminars, and onsite practical training. The evaluation recorded assessments of the requirement profile, design, and opportunities for skills acquisition; evaluation of the seminar and internship; and questions on the overall assessment. The new concept was applied to four passes in the fourth academic year. Atotal of 152 students completed the radio-oncology learning module, which was evaluated by 46students. Forty students considered the course duration to be appropriate for the material covered, and most students stated that their prior knowledge had been sufficient. The level of difficulty of the content was rated by the students as somewhat too high. The design of the digital course, the opportunity to acquire skills, the seminar course, and the practical course were mostly rated positively. Through digital redesign, ateaching concept can be implemented that combines self-determined learning, professional exchange with doctors, and clinical practice experience. The concept can be transferred to other areas because it combines theoretical knowledge transfer with synchronous teaching and clinical experience. The results of the evaluation show that the students rated the new concept well.

Trends in single-fraction palliative radiotherapy across the COVID-19 pandemic in Japan: a nationwide claims study.

This study aimed to evaluate the recent trends in single-fraction conventional radiotherapy (CRT) as palliative treatment in Japan, using data from the National Database published by the Ministry of Health, Labor, and Welfare. Data from fiscal year (FY) 2014 to FY2022, specifically related to the utilization of single-fraction CRT, were analyzed. Multi-fraction CRT, stereotactic body radiotherapy (SBRT), intensity-modulated radiotherapy (IMRT), and brachytherapy were excluded. The primary outcome was the cumulative and annual number of single-fraction CRT courses. Additionally, quarterly course data from FY2019 to FY2022, the period for which monthly data were available, were assessed to evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on single-fraction CRT utilization. Of the total 2 315 607 radiotherapy courses, we identified 33 221 single-fraction CRT courses after excluding multi-fraction CRT (n = 1 835 650), SBRT (n = 33 935), IMRT (n = 332 827), and brachytherapy (n = 113 195). The annual number of single-fraction CRT courses increased from 1730 in FY2014 to 5642 in FY2022, with an average annual growth rate of 0.28 (range: -0.07 to 0.65). Outpatient courses significantly increased, particularly from FY2019 onward, surpassing inpatient courses in FY2022 (2914 vs 2728). The highest annual increase was observed in FY2020, particularly from April to December, although this upward trend did not persist in 2021. In conclusion, single-fraction CRT has exhibited a consistent upward trend, highlighting its expanding role in palliative radiotherapy. Although the COVID-19 pandemic temporarily accelerated this trend, its impact has already subsided, with growth rates returning to pre-pandemic levels.

Linear regression analysis for complete blood count parameters during radiotherapy.

This study aimed to evaluate the correlations between complete blood count (CBC) during radiotherapy and patient and treatment factors. Data of cancer patients, including age, sex, concurrent chemotherapy (CCRT), radiotherapy dose (equivalent dose in 2‑Gy fractions with an alpha/beta value of 10 Gy, EQD2Gy10), radiotherapy location, and baseline CBC were collected. Linear regression was used to determine results during radiation. Validation data comprised 20% of the whole cohort. Atotal of 496 radiotherapy courses and 1884 weekly CBC results during treatment were analyzed. Baseline hemoglobin (Hb) was positively associated with subsequent Hb. Each 1 g/dL increase in baseline Hb predicted a0.73 g/dL increase in Hb during treatment (95% confidence interval [CI] 0.7-0.76). Male sex was associated with a0.16 g/dL higher Hb (95% CI 0.04-0.29), while female sex showed the opposite trend. CCRT was associated with a0.18 g/dL reduction in Hb (95% CI -0.33 to -0.03). Radiotherapy to the pelvis, bone, and head and neck regions resulted in Hb reductions of 0.18, 0.34, and 0.94 g/dL, respectively (95% CI -0.33 to -0.03, -0.53 to -0.15, and -1.26 to -0.62, respectively), while brain irradiation increased Hb by 0.22 g/dL (95% CI 0.05-0.38). Age, cumulative dose, and thoracic irradiation did not show asignificant correlation with Hb changes. Adjusted R‑squared for the development and validation data were 0.6 and 0.71 for Hb, 0.42 and 0.11 for white blood cell count, 0.36 and 0.32 for neutrophils, 0.42 and 0.06 for absolute neutrophil count, and 0.43 and 0.36 for platelets, respectively. Hb levels during radiotherapy could be explained using linear regression, although they did not negatively correlate with cumulative dose.

FLASH proton reirradiation, with or without hypofractionation, reduces chronic toxicity in the normal murine intestine, skin, and bone.

The normal tissue sparing afforded by FLASH radiotherapy is being intensely investigated for potential clinical translation. Here, we studied the effects of FLASH proton radiotherapy (F-PRT) in the reirradiation setting, with or without hypofractionation. Chronic toxicities in three murine models of normal tissue toxicity including the intestine, skin, and bone were investigated. In studies of the intestine, single-dose irradiation was performed with 12 Gy of standard proton RT (S-PRT), followed by a second dose of 12 Gy of F-PRT or S-PRT. Additionally, a hypofractionation scheme was applied in the reirradiation setting (3 x 6.4 Gy of F-PRT or S-PRT, given every 48 hrs). In studies of skin/bone of the murine leg, 15 Gy of S-PRT was followed by hypofractionated reirradiation with F-PRT or S-PRT (3 x 11 Gy). Compared to reirradiation with S-PRT, F-PRT induced less intestinal fibrosis and collagen deposition that was accompanied by significantly increased survival rate, demonstrating its protective effects on intestinal tissues in the reirradiation setting. In previously irradiated leg tissues, reirradiation with hypofractionated F-PRT created transient dermatitis that fully resolved in contrast to reirradiation with hypofractionated S-PRT. Lymphedema was also alleviated after a second course of radiation with F-PRT, along with significant reductions in the accumulation of fibrous connective tissue in the skin, compared to mice reirradiated with S-PRT. The delivery of a second course of fractionated S-PRT induced tibial fractures in 83.3% of the mice, whereas only 20% of mice reirradiated with F-PRT presented with fractures. These studies provide the first evidence of the sparing effects of F-PRT in the setting of hypofractionated reirradiation. The results support FLASH as highly relevant to the reirradiation regimen where it exhibits significant potential to minimize chronic complications for patients undergoing RT.

IMMEDIATE RESULTS OF SURGICAL TREATMENT OF STAGE III FACIAL SKIN CANCER: A CLINICAL CASE

Relevance: Most cases of skin cancer are widespread on continents with predominantly fair-skinned populations and high levels of ultraviolet radiation exposure, such as Australia and New Zealand. In Kazakhstan, as well as throughout the world, there is an increasing trend in the incidence of skin cancer. In 2023, 4,481 new cases of this disease were registered, of which 85% were basal cell carcinoma. Kazakh Institute of Oncology and Radiology (Almaty, Kazakhstan) utilizes various methods, including surgical excision, which remains the main treatment method, as well as radiation therapy, electrochemotherapy, and cryotherapy. The study aimed to describe a case of surgical treatment of a patient under local anesthesia with stage III basal cell skin cancer of the zygomatic region on the left, accompanied by clinical bleeding and pain. Methods: The article describes a case of surgical treatment of skin cancer under local infiltration anesthesia. Results: The postoperative period proceeded without complications. The cosmetic result was assessed as satisfactory. The patient did not experience difficulties with facial movements, and no sensory disturbances were observed. The patient was discharged home with recommendations to consult a radiologist considering the tumor histotype to decide on the possibility of a postoperative course of radiation therapy. Conclusion: The presented case demonstrates the possibility of performing surgery for stage II-III skin cancer with complete closure of the defect under local anesthesia. This may be an alternative to general anesthesia in patients with concomitant diseases and a high risk of complications. The method can be used in the absence of tumor invasion into the bone to avoid the difficulties associated with general anesthesia.

The experience of using chemoradiotherapy for esophageal cancer with the FOLFOX chemotherapy regimen

Introduction. For an extended period, numerous studies have been conducted to find the optimal treatment regimen for esophageal cancer. Chemoradiotherapy has demonstrated satisfactory results in the treatment of localized and locally advanced forms of this disease. However, the search for the best chemotherapy regimen in combination with radiotherapy remains a current focus of many researchers.Aim. To evaluate the effectiveness and safety of chemoradiotherapy (CRT) using the FOLFOX regimen in patients with esophageal cancer.Materials and methods. A prospective study was conducted at the Ulyanovsk Regional Clinical Oncology Dispensary. The analysis included patients who received chemoradiotherapy with the FOLFOX regimen from December 1, 2022, to March 1, 2024. A total of 19 cases of esophageal cancer treatment at stages I–III were analyzed. Radical surgical treatment was subsequently performed on 5 patients (26.3%). The characteristics of the studied patients were evaluated according to a standardized protocol.Results. In the study group, 18 patients (94.7%) completed the planned course of treatment. One patient received an incomplete course of radiotherapy but completed the entire planned chemotherapy. The most common hematologic complication was leukopenia, observed in 9 patients (47.3%) after the full course of chemoradiotherapy. No cases of febrile neutropenia were reported. The hematologic complications were manageable and did not lead to the discontinuation of treatment. Among non-hematologic complications, the most frequently reported were grade 1–2 nausea in 11 patients (58%) and grade 1–2 vomiting in only 2 cases (10%), which was effectively controlled with antiemetic therapy. Overall and relapse-free survival were assessed. The reason for discontinuing radiotherapy in 1 patient (5.3%) was ulcerative stomatitis. Surgery was performed on 5 patients, with tumor regression (TRG) grades 1–2 according to the Mandard scale observed in 4 of them (80%). One patient (20%) had a TRG 3 response.Conclusions. After chemoradiotherapy with the FOLFOX regime in patients with squamous cell carcinoma of the esophagus, the rate of therapeutic tumor regression (TRG1–2) in operated patients reached 80%. One-year relapse-free survival was 58%, one-year overall survival was 73%, indicating the effectiveness and safety of this chemotherapy regimen as part of the comprehensive treatment of esophageal cancer.

Radiotherapy and inflammaging: the influence of prostate cancer radiotherapy on systemic inflammation

PurposeThe present study was performed to investigate the association of prostate cancer radiotherapy with inflammaging, a condition characterized by the elevation of inflammatory blood parameters that significantly increases the susceptibility to the occurrence or progression of age-related conditions.Patients and MethodsA total of 306 patients treated with curative radiotherapy (RT) for prostate cancer were enrolled into the prospective study. Aging-related inflammatory parameters including C-reactive protein (CRP), albumin, fibrinogen, cholesterol, platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR) were analyzed before and at the end of RT, and 3 and 15 months after completion of the RT. Statistical analysis was performed using non-parametric variance analysis.ResultsOverall variance analysis showed a significant influence of RT on all inflammatory parameters (p < 0.001) with the exception of CRP (p = 0.498). Pairwise analysis revealed a significant elevation of fibrinogen (p = 0.041), NLR (p < 0.001), and PLR levels (p < 0.001) as well as a significant decrease of albumin (p < 0.001) and cholesterol levels (p < 0.001) during the RT course. After completion of RT, a significant recovery was detected for NLR, PLR, albumin and cholesterol. However, 15 months after RT, PLR, fibrinogen, and cholesterol remained significantly lower when compared to the baseline (p < 0.001).ConclusionOur results indicate that radiation therapy triggers chronic inflammatory processes that could contribute to the development, acceleration or worsening of age-related alterations and conditions. Further investigations to estimate the long-term consequences of curative radiation therapy on clinical manifestations of aging are warranted.

A Study on Breast Cancer Patient Care Using Chatbot and Video Education for Radiation Therapy: A Randomized Controlled Trial.

This study aimed to evaluate the use of chatbot and video education to reduce anxiety in patients with breast cancer undergoing radiation therapy (RT). This randomized controlled trial included patients with breast cancer scheduled for RT after surgery at an outpatient department of radiation oncology in a cancer center, randomly assigned to 4 groups: (1) video + chatbot, (2) video + paper, (3) paper + chatbot, and (4) paper + paper. In each group, patients received information regarding the treatment process and were frequently asked questions using the designated tool. Patient anxiety was evaluated using the Amsterdam preoperative anxiety and information scale (APAIS), state-trait anxiety inventory (STAI), and linear analog scale assessment (LASA) at 3 points: (1) initial outpatient visit (T0), (2) before the RT course (T1), and (3) after the RT course (T2). The primary endpoint was APAIS, and the secondaries were STAI and LASA. A mixed-model repeated-measures ANOVA was conducted with time as a within-group factor and treatment conditions as a between-group factor. The final analysis included 145 patients. No significant interaction was observed between groups and time for the APAIS, STAI, or LASA. Although unplanned, analyses were conducted using the age of 50 years as the cutoff, based on a previous systematic review of digital literacy in the medical field. A trend toward reduced APAIS was found among patients aged ≤50 years who used the chatbot (per-protocol subgroup). In the video + chatbot group, the APAIS score decreased from 3.06 (T0) to 1.88 (T2); in contrast, in the paper + paper group, it decreased from 2.42 (T0) to 2.06 (T2). In contrast, no significant interaction was observed in the APAIS of per-protocol patients aged ≥50 years. Overall, no significant differences were found in the effectiveness of different types of educational media in reducing patients' anxiety. However, for young patients who actively use video or chatbot resources, education through digital media may meaningfully reduce their anxiety during the RT process.

Outcomes With Radiation Therapy as Primary Treatment for Unresectable Cutaneous Head and Neck Squamous Cell Carcinoma.

Unresectable cutaneous squamous cell cancer of the head and neck (HNcSCC) poses treatment challenges in elderly and comorbid patients. Radiation therapy (RT) is often employed for locoregional control. This study aimed to determine progression-free survival (PFS) and overall survival (OS) outcomes achieved with upfront RT in unresectable HNcSCC. It also aimed to determine the impact of varying RT dose regimes on disease outcomes. A retrospective cohort study was conducted of patients with unresectable HNcSCC treated with first-line RT at a tertiary teaching hospital in Sydney, Australia between 2015-2024. Patient, disease, treatment and follow-up data were extracted from the electronic records. Of 36 patients, 67% were male, median age was 81 years, and median Charlson Comorbidity Index was 6.5. Median follow-up was 21 months. 83% of RT courses were delivered via intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT). Objective response rate was 97%. Patients were grouped into low-dose RT receiving biologically equivalent dose (BED) <60Gy (n = 18) or high-dose RT (BED ≥ 60Gy, n = 18). Infield progression-free survival (PFS) at 6 months was 56% and 78%, respectively. Overall survival at 6 months was 83% and 89%, and by 24 months 31% and 65%, respectively. RT is an efficacious treatment that can be tailored to individual patient contexts with unresectable HNcSCC. It has a high response rate overall, with higher doses producing longer disease control. Some patients with poorer functional status receiving low-dose RT can still achieve a sustained response. Future comparisons of outcomes and cost-effectiveness with emerging treatments such as immunotherapy will be important in guiding management for frail patients with unresectable disease.

Комбинированный метод лечения рака ротоглотки

Purpose: To demonstrate the possibility of a combined approach in the treatment of a patient with locally advanced squamous cell carcinoma of the nasopharynx, complicated by massive erosive bleeding using endovascular embolization, proton therapy and targeted therapy. Material and methods: The Federal Scientific Research Center for Reconstruction and Research has developed a method of a combined approach to the treatment of patients with malignant neoplasms of the nasopharynx, during which endovascular embolization and proton beam therapy in combination with targeted therapy are consistently used. Results: A set of sequential treatment procedures and drug administration allowed us to eliminate life-threatening bleeding, normalize the patient’s general condition, conduct a course of proton radiation therapy for a patient with locally advanced squamous cell carcinoma of the nasopharynx, complicated by massive bleeding, and achieve stable local control over the process. Conclusion: The use of the described tactics in the treatment of tumors of the nasopharynx and oral cavity allows in a short period to move from urgent endovascular occlusion of bleeding vessels to the stages of special antitumor treatment, providing a combined approach to the treatment of head and neck tumors.

Efficacy of radiotherapy for bone metastasis in breast cancer patients treated with cyclin-dependent kinase 4/6 inhibitors

BackgroundIn patients diagnosed withestrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, bone metastasesemerge as theprimary siteofsignificant tumor burden. Cyclin-dependent kinase 4/6 (CDK4/6i) inhibitorsare thegold standard in this clinical scenario, while radiotherapy (RT) represents a valuable addition. However, data on the efficacy of this combination remain scarce. We aimed to evaluate efficacy of RT in bone metastatic breast cancer patients treated with CDK4/6 inhibitors. Materials and methods398 patients (pts) with ER-positive HER2-negative breast cancer with bone metastases treated with CDK4/6i between 2018–2024 were analyzed. A total of 114 pts received 177 bone RT concurrently with CDK4/6i or within 6 months before CDK4/6i initiation, including 34 courses of stereotactic-body RT and 143 courses of conventional RT. ResultsThe median progression-free survival (PFS) in pts who received bone RT was 31.0 months, compared to 26.3 months in pts without bone RT. The 2-y PFS for pts with bone RT was 57.1 % [95 % CI: 46.3–66.6 %] vs. 53.2 % [95 % CI: 46.3–59.6 %] for patients without bone RT (p = 0.51). The median overall survival (OS) for pts who received bone RT was 49.1 months, compared to 40.5 months for pts without bone RT. The 3-y OS for pts with bone RT was 63.7 % [95 % CI: 51.5–73.5 %] vs. 55.0 % [95 % CI 46.6–62.6 %] for pts without bone RT (p = 0.50). The 3-y local control for irradiated patients was 86.9 % [95 % CI 72.2–94.1 %]. ConclusionsIn this study, we present the largest cohort published to date of breast cancer patients who received CDK4/6i alongside bone-directed RT. Although the observed differences in survival were not statistically significant, RT remains a viable treatment modality in metastatic breast cancer in some patients.

Microorganisms isolated from thermoplastic masks and storage racks in head and neck cancer patients with radiation dermatitis

Healthcare-associated infections (HAIs) remain a critical public health issue, as they contribute to prolonged treatment duration, increased healthcare costs, and heightened risks of morbidity and mortality. In head and neck cancer patients undergoing radiotherapy, thermoplastic masks (TMs), which come into direct contact with the skin, represent a potential vector for infection. Additionally, the storage racks where these masks are kept may also facilitate microorganism transmission. Our study aimed to isolate and identify microorganisms from infective skin lesions secondary to radiation dermatitis in head and neck cancer patients, as well as from the TMs and storage racks, and to evaluate the antibiotic resistance profiles of the isolated microorganisms. The study included 71 locally advanced head and neck cancer patients who underwent radiotherapy between August 2022 and November 2023. Patients were monitored daily, and their skin evaluations were made according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Grade 2 and 3 radiodermatitis was observed in 29 of these 71 patients. Samples were collected using sterile swabs from the skin lesions on the head and neck area, the inner surfaces of the TM, and the storage rack from 29 patients. Samples were inoculated into enrichment and selective media. After the growing microorganisms were identified, antimicrobial susceptibility was evaluated using conventional methods and automated systems according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. At least one type of microorganism was isolated from the skin samples of infected patients, and double growth was detected in two patients. Among the samples, 2 were methicillin-resistant coagulase-negative Staphylococcus (MRCNS), 1 was methicillin-resistant Staphylococcus aureus (MRSA), 1 was Candida albicans (C. albicans), 15 were methicillin-sensitive coagulase-negative Staphylococcus (MSCNS), 1 was methicillin-sensitive Staphylococcus aureus (MSSA), 1 was Bacillus subspecies (Bacillus spp.) and 3 were Corynebacterium diphtheriae (C. diphtheriae). Coagulase-negative Staphylococcus strains were isolated from the skin of 14 of 19 patients with grade 2 radiation dermatitis, whereas CNS strains were isolated from only 2 of 10 patients with grade 3 radiation dermatitis. Among the gram-negative bacteria, 3 Pseudomonas aeruginosa (P. aeruginosa), 2 Enterobacter cloacae (E. cloacae), 1 Klebsiella pneumoniae (K. pneumoniae) and 1 Moraxella catarrhalis (M. catarrhalis) strain were isolated. Sixteen (55.1%) of the TMs used in 29 patients and 20 (68.9%) of the storage racks harbored microorganisms, including HAI agents and flora bacteria. Bacteria colonize TMs and storage racks where they are risk factors for secondary skin infections in radiation dermatitis lesions that develop on the skin of head and neck cancer patients. Decontamination procedures should be meticulously applied to surfaces such as TMs and their storage racks during the course of radiotherapy.

Cost of Care Related to Radiation Treatment in Locally Advanced Rectal Cancer: Short Course Radiation Therapy vs Long Course Chemoradiation

Cost of Care Related to Radiation Treatment in Locally Advanced Rectal Cancer: Short Course Radiation Therapy vs Long Course Chemoradiation

Dual-encoder architecture for metal artifact reduction for kV-cone-beam CT images in head and neck cancer radiotherapy

During a radiotherapy (RT) course, geometrical variations of target volumes, organs at risk, weight changes (loss/gain), tumor regression and/or progression can significantly affect the treatment outcome. Adaptive RT has become the effective methods along with technical advancements in imaging modalities including cone-beam computed tomography (CBCT). Planning CT (pCT) can be modified via deformable image registration (DIR), which is applied to the pair of pCT and CBCT. However, the artifact existed in both pCT and CBCT is a vulnerable factor in DIR. The dose calculation on CBCT is also suggested. Missing information due to the artifacts hinders the accurate dose calculation on CBCT. In this study, we aim to develop a deep learning-based metal artifact reduction (MAR) model to reduce the metal artifacts in CBCT for head and neck cancer RT. To train the proposed MAR model, we synthesized the kV-CBCT images including metallic implants, with and without metal artifacts (simulated image data pairs) through sinogram image handling process. We propose the deep learning architecture which focuses on both artifact removal and reconstruction of anatomic structure using a dual-encoder architecture. We designed four single-encoder models and three dual-encoder models based on UNet (for an artifact removal) and FusionNet (for a tissue restoration). Each single-encoder model contains either UNet or FusionNet, while the dual-encoder models have both UNet and FusionNet architectures. In the dual-encoder models, we implemented different feature fusion methods, including simple addition, spatial attention, and spatial/channel wise attention. Among the models, a dual-encoder model with spatial/channel wise attention showed the highest scores in terms of peak signal-to-noise ratio, mean squared error, structural similarity index, and Pearson correlation coefficient. CBCT images from 34 head and neck cancer patients were used to test the developed models. The dual-encoder model with spatial/channel wise attention showed the best results in terms of artifact index. By using the proposed model to CBCT, one can achieve more accurate synthetic pCT for head and neck patients as well as better tissue recognition and structure delineation for CBCT image itself.

Increasing the effectiveness of total-skin electron beam therapy by reducing the manifestations of radiation dermatitis in patients with primary lymphomas. A comparative randomized prospective study

Background. One of the main adverse events that significantly reduce the quality of life of patients and limit the total focal dose is radiation-induced skin reactions (RISR). Their timely diagnosis, prevention, and treatment remain urgent tasks of modern radiotherapy. Aim. To improve the effectiveness of total skin irradiation (TSI) in patients with primary skin lymphomas by reducing the clinical manifestations of RISR by using additional therapy with a hydrogel containing active components with vasoprotective and anti-inflammatory action. Materials and methods. A comparative randomized prospective study was conducted, including data from 52 patients who received electron TSI by conventional fractionation at a total focal dose of 14 to 30 Gy for primary cutaneous lymphomas at the Granov Russian Research Center of Radiology and Surgical Technologies from September 2021 to January 2024. Before the first TSI session, during treatment and 2 weeks after the end of radiation therapy, all patients underwent assessment for RISR, quantitative assessment of various degrees of severity of radiodermatitis using instrumental methods and assessment scales; for the observation group, a therapeutic regimen for the prevention and treatment of RISR was used, including a hydrogel with troxerutin (2%) and trolamine (0.07%), and in the control group, basic skin care using moisturizers. Results. Analysis of the physiological parameters of the skin showed statistically significant differences between the study groups: patients of the study group (group I; 30 subjects receiving the above-mentioned therapeutic regimen) compared with the control group (group II; 28 subjects who did not receive specific treatment for radiodermatitis) reported significantly lower rates of erythema (386±12.3 and 572±14.4; p=0.005), transepidermal water loss (25±0.3 and 38±0.4 g/m2/h; p0.001) and a decrease in peak endothelial-dependent vasodilation of microvasculature and blood flow in the skin. A lower proportion of severe radiodermatitis (86.3 and 73.3%; p0.05) and a statistically significant difference in the subjective quality of life scores by the 29-point Skindex-29 scale by an average of 22.2% were also found. Conclusion. A comparative analysis of the quantitative indicators of radiodermatitis in the study group and the control group showed that the topical application of the hydrocolloid gel containing troxerutin and trolamine reduces the clinical manifestations of RISR concerning objectively measured physiological parameters of the skin and blood flow parameters of the microvasculature measured by high-frequency ultrasound, thus improving the quality of life of patients during and after the course of radiation therapy.

BIOM-39. GENOMIC AND CLINICAL ASSOCIATIONS WITH RADIATION NECROSIS IN PATIENTS WITH DIFFUSE INFILTRATING GLIOMAS

Abstract BACKGROUND Radiation necrosis (RN) is a complication of radiotherapy (RT) that can significantly affect quality of life and outcomes in patients with gliomas. Clinical and molecular factors predisposing patients to RN are not clearly established. We hypothesize that clinicogenomic data can be leveraged to identify patients at high risk for RN. METHODS We identified patients from 2014-2024 with diffuse gliomas and RN diagnosed based on Advanced-Brain-Tumor-Imaging which includes conventional MRI, 3 perfusion parameters, spectroscopy and/or pathology at MD Anderson. Inclusion criteria included diagnosis of RN 12-weeks after RT and concordance of 4 ABTI parameters. For each case, we identified 2 controls who were gender-,diagnosis-, and age-matched using a nearest neighborhood algorithm. We evaluated the correlation between 15 most mutated genes in baseline tissue and occurance of RN. A logistic regression model was employed to assess the multivariable relationship between patient characteristics, gene mutations, and RN. RESULTS We identified 62 patients with RN; 50 glioblastoma (80.6%), 8 diffuse astrocytoma (12.9%) and 4 oligodendroglioma (6.5%). Time from RT to RN diagnosis was 254 days (IQR 154-483). 18(29%) of RN cases and 29(24.4%) of controls had received more than one course of RT. Patients treated with bevacizumab before RT had significantly lower odds of developing RN compared to those who did not receive bevacizumab (OR 0.103 [0.011 – 0.960], p=0.0459). BRAF mutations were more frequent in the RN cohort (8.1% vs. 2.4%) and patients with BRAF mutation were more likely to have RN than those without BRAF mutation (OR 6.842 [1.2, 39.01], p=0.0304). Age, gender, diagnosis, IDH, MGMT or 1p19q status were not associated with RN. CONCLUSION We found that bevacizumab administration was associated with a significant reduction in RN development. We also found a novel association between presence of BRAF mutations and increased risk of RN in glioma patients, which warrants further investigation.

CTNI-80. 177LU-DOTATATE IN PATIENTS WITH RECURRENT MENINGIOMA

Abstract BACKGROUND There are no effective medical therapies for patients with meningioma who progress after surgical and radiotherapeutic interventions. Somatostatin receptor type 2 (SSTR2) represents a promising treatment target in meningiomas. Here, we describe our experience with use of 177Lu-DOTATE in recurrent meningioma PATIENTS AND METHODS This is a retrospective study. All patients had progressive intracranial meningiomas and were heavily pre-treated. Patients underwent 68Ga-DOTATATE PET-MRI at baseline and received 177Lu-DOTATATE every eight weeks for up to four doses. We collected patient demographics, tumor grade, treatment history prior to starting 177Lu-DOTATATE, duration of treatment, toxicities, overall survival (OS) and progression-free survival (PFS). Descriptive statistics were used to summarize patient’s characteristics. RESULTS Seven patients (female = 2, male = 5) with progressive meningiomas (WHO 1 = 1, 2 = 1, 3 = 5) were enrolled. Median age was 56 (range 41-72) years. All patients previously underwent tumor resection and at least one course of radiation. Treatment with 177Lu-DOTATATE was well tolerated. Three patients achieved PFS-6. One patient with malignant meningioma remains progression free at 13 months. Three patients remain on active treatment. Best radiographic response was stable disease (SD) in six patients. CONCLUSIONS Treatment with 177Lu-DOTATATE was well tolerated and demonstrated encouraging efficacy. Updated survival data will be presented.

RADT-28. THE ROLE OF CRANIAL RE-IRRADIATION IN EGFR MUTANT LUNG CANCER PATIENTS WITH BRAIN METASTASES

Abstract INTRODUCTION Re-irradiation with stereotactic radiosurgery (SRS) or whole-brain radiotherapy (WBRT) may be used for treating recurrent brain metastases. Here, we are reporting on the rate of cranial re-irradiation based on our institutional experience in patients with mutated Epidermal Growth Factor Receptor Non-Small Cell Lung Cancer (mEGFR-NSCLC). METHODS This is a retrospective review of patients from three NYP-WCM hospitals with brain metastases treated with radiotherapy and Tyrosine Kinase Inhibitors (TKIs) from December 2012 to May 2023. RESULTS Ninety-eight patients (60.5%) out of 162 with brain metastases from mEGFR-NSCLC were treated with radiation. Twenty-seven patients (27.5%) were treated with WBRT. Among 71 patients treated with SRS, 10 (14.1%) patients underwent surgical resection of the dominant brain lesion followed by fractioned SRS (FSRS) to the surgical bed. Sixty-one (85.9%) patients received SRS for intact brain lesions ranging from single fraction 16-20Gy to FSRT with 24Gy –30Gy in 3-5 fractions based on the size and eloquence of the brain site of the brain metastasis. In the SRS group, fifteen (21.1%) patients required at least one more course of cranial irradiation. The mean duration of local intracranial control between the first and the second course of radiation was 19.6 months [range from 2.0- 56.7 months], while from the start of TKI to the first intracranial failure was 11.3 months [0.8m-45.3 months]. In the WBRT group, two patients (7.4%) were treated with another course of WBRT 20Gy in 5 fractions. These two patients started TKI simultaneously with their first course of WBRT; the mean duration of intracranial local control was 12.8 months [range from 11.6-14.1 months]. Both patients suffered significant cognitive declines. CONCLUSION In the Tyrosine Kinase Inhibitor era, patients with brain metastases from mEGFR-NSCLC have protracted progression-free survival. Multiple courses of cranial re-irradiation may be needed. Stereotactic radiotherapy should be preferred for the best results in preserving cognitive functions.

NCOG-03. DESCRIPTIVE ANALYSIS AND OUTCOME COMPARISON BETWEEN PATIENTS WITH GLIOBLASTOMA MULTIFORME WHO RECEIVE 15 VERSUS 30 FRACTIONS OF RADIOTHERAPY: A RETROSPECTIVE CHART REVIEW

Abstract The morbidity and efficacy of abbreviated radiotherapy (RT) courses for Glioblastoma (GB) in patients over 60 years have been studied, however, outcomes in younger patients are not yet well-described. This study aims to characterize the outcomes of patients receiving either a standard versus abbreviated RT course. A retrospective chart review at Kingston Health Sciences Centre from June 2014 to March 2021 included patients with GB receiving either 40Gy in 15 fractions (Fr) or 60Gy in 30Fr. Data on age, ECOG score, and concurrent chemotherapy (Temozolomide, TMZ) were collected. Outcomes compared were treatment completion, hospital admission during treatment, progression-free survival (PFS), and overall survival (OS). Records of 156 patients (median age 61 years, range 25-87 years) were reviewed. Of these, 89 received 30Fr and 67 received 15Fr (p=0.51). MGMT methylation was recorded in 54 (35%) patients; of these, 27 received 15Fr and 27 received 30Fr. Median follow-up was 12 months. While PFS did not significantly differ between 15Fr vs. 30Fr (6 vs. 11 months, respectively; p=0.08), OS was significantly different (8 vs. 16 months, respectively; p&amp;lt;0.001). Patients receiving 15Fr vs 30F tended to have higher ECOG scores (p&amp;lt;0.001) and were older (median: 71 [range 45-87] vs. 57 [range 25-69] years; p&amp;lt;0.001). Individuals receiving TMZ were more likely to receive 30Fr (67.5% vs. 32.5% for 15Fr; p&amp;lt;0.001). Completion rates were higher for 30Fr (94.3%) than 15Fr (83.6%; p=0.03). Hospital admission rates did not differ (p=0.51). In summary, patients receiving 15Fr (40Gy) typically have poorer functional status, are less likely to receive chemotherapy, and less likely to complete treatment compared to those receiving 30Fr. Hospital admission rates during treatment are low (13%) and similar for both groups. OS, but not PFS, is better for patients receiving 30Fr compared to 15Fr.