Primary Radiation Research Articles

Treatment patterns and prognosis of patients with clear cell adenocarcinoma of the cervix: A population-based cohort study.

To describe treatment patterns and prognoses for clear cell adenocarcinoma of the cervix (CCAC), a poorly understood rare tumor. A retrospective case‒control study was conducted using the Surveillance, Epidemiology, and End Results (SEER) database, focusing on females diagnosed with CCAC between 2000 and 2019. Kaplan‒Meier analysis, propensity score matching, Cox regression analysis, and subgroup analysis were used to assess treatment outcomes and risk factors. Of the 52,153 patients with cervical cancer in the SEER database, 528 had CCAC. Overall survival (OS) was worse for patients with early-stage and locally advanced CCAC disease, although no differences in survival were observed for patients with stage IVB disease compared to those with other histologies. In our investigation into treatment patterns, we have discovered that surgical treatment was the preferred choice for the majority of patients with locally advanced CCAC (58.5%). Further, Kaplan-Meier analysis revealed that surgery improved OS in CCAC patients (65.6% vs. 25.3%, P=0.000), with similar results in locally advanced-stage patients (57.9% vs. 26.7%, P=0.000). Moreover, multivariate Cox regression analysis revealed that surgery was significantly associated with a more favorable prognosis in CCAC patients with locally advanced disease (HR 0.299, 95% CI: 0.153-0.585, P=0.000). Consistent findings were observed following propensity score matching (HR 0.283, 95% CI: 0.106-0.751, P=0.011). According to the subgroup analyses, surgical intervention continued to show a beneficial effect on CCAC patients with locally advanced disease (HR=0.31, 95% CI 0.21-0.46, P<0.001). In particular, we also found that compared to patients who received primary radiotherapy (RT), those with CCAC who underwent radical surgery exhibited a significantly prolonged OS in locally advanced CCAC patients. Furthermore, multivariate Cox regression analysis revealed that surgery was associated with better outcomes in patients with stage IB3-IIA2 and locally resectable stage IIIC patients (HR 0.207, 95% CI=0.043-0.991, P=0.049). However, this trend was not observed for patients with stage IIB-IVA (except locally resectable stage IIIC) CCAC. Surgery should be considered the preferred treatment option for patients with locally advanced CCAC at stage IB3-IIA2 and locally resectable stage IIIC.

Factors associated with total laryngectomy following organ-preserving treatment of laryngeal SCC.

A subset of laryngeal squamous cell carcinoma (LSCC) patients undergoing larynx preserving treatment ultimately require total laryngectomy (TL) for oncologic or functional reasons. This study aims to identify TL risk factors in these patients. Retrospective cohort study using Veterans Affairs (VA) database. T1-T4 LSCC cases treated with primary radiotherapy (XRT) or chemoradiotherapy (CRT) were assessed for TL and recurrence. Binary logistic and Cox regression and Kaplan-Meier analyses were implemented. Of 5390 cases, 863 (16.0%) underwent TL. On multivariable analysis, age (adjusted odds ratio: 0.97 [0.96-0.98]; p < .001) and N3 disease (0.42 [0.18-1.00]; p = .050) were associated with reduced risk of TL, whereas current alcohol use (1.22 [1.04-1.43]; p = .015) and >T1 disease (T2, 1.76 [1.44-2.17]; p < .001; T3, 2.06 [1.58-2.68]; p < .001; T4, 1.79 [1.26-2.53]; p = .001) were associated with increased risk of TL. However, N2 (adjusted hazard ratio: 1.30 [1.10-1.55]; p = .003) and N3 (2.02 [1.25-3.26]; p = .004) disease were associated with an increased risk for local recurrence. Compared to XRT, treatment with CRT was associated with reduced risk for local recurrence after adjusting for other factors (0.84 [0.70-0.99]; p = .044). Those who do not receive TL following local recurrence have poorer disease-specific survival (log-rank, p < .001). In patients without local recurrence, N2 disease was associated with a fourfold increase in risk of TL (4.24 [1.83-9.82]; p < .001). Advanced nodal stage was associated with reduced rates of salvage TL in the setting of local recurrence, and subsequent worse prognosis after recurrence. Conversely, advanced nodal stage may increase the risk for functional salvage TL in patients without recurrence. Level 3.

Primary tumor heterogeneity on pre-treatment [68Ga]Ga-PSMA PET/CT for the prediction of biochemical recurrence in prostate cancer

PurposeThe aim of this study is to research the value of the texture analysis of primary tumors in pre-treatment [68Ga]Ga-PSMA PET in the prediction of the development of biochemical recurrence (BCR) in prostate cancer patients who underwent definitive therapies. Methods51 patients with prostate adenocarcinoma who had a pre-treatment [68Ga]Ga-PSMA-11 PET/CT and underwent definitive radiotherapy (RT) or radical prostatectomy (RP) were included in the study. Demographics, clinicopathologic features, the presence of BCR, and the last follow-up date of patients were recorded. Textural and conventional PET parameters (maximum standardized uptake value (SUVmax), total lesion-PSMA (TL-PSMA), and PSMA-tumor volume (PSMA-TV)) were obtained from PET/CT images using LifeX program. Parameters were grouped using the Youden index in ROC analysis. Factors predicting the BCR were determined using Cox regression analyses. Results29 (56.9%) patients have received primary curative RT, while the remaining 22 (43.1%) patients have undergone RP. 5 (22.7%) patients with RP and 3 (10.3%) patients with curative RT have developed BCR during the follow-up. INTENSITY-BASED-minimum grey level (P=.050), GLCM-sum variance (P=.019), and GLCM-cluster prominence (P=.050) were associated with BCR in univariate analysis. INTENSITY-BASED-minimum grey level (P=.009) and GLCM-sum variance (P=.004) were found as independent predictors of BCR in the multivariate analysis. ConclusionTumor heterogeneity on pre-treatment [68Ga]Ga-PSMA PET is associated with a high risk of BCR in PCa patients who underwent definitive therapies.

Reirradiation in head and neck squamous cell carcinoma; prognostic indicators, oncologic and functional outcomes

ObjectivesPatients with recurrent squamous cell carcinoma of the head and neck (HNSCC) have a poor prognosis and limited therapeutic alternatives. While reirradiation is feasible, it is usually associated with high treatment toxicity and is not yet considered the standard of care. Based on current NCCN guidelines, in the context of very advanced head and neck cancer (recurrent and/or persistent disease), surgical intervention is explored initially with/without adjuvants while unresectable disease is approached with radiation and/or systemic therapies. Specific and reliable prognostic indicators for both -oncologic and functional outcomes- have yet to be defined for this population. MethodsRetrospective chart review of 54 patients treated with reirradiation at a tertiary academic institution between January of 1998 and January of 2024. Only patients with non-metastatic recurrent, and second primary HNSCC were included in the series. Demographics, staging, radiation dose and technique, additional therapy, histopathologic variables, EORTC toxicity, pre- and post-treatment PEG/tracheotomy dependency and oncologic outcomes were retrieved. ResultsThe study cohort consisted of 54 patients (37 males, 17 females) with HNSCC, averaging 62.7 years in age. Initial tumors were locally advanced in over 42 % of cases, with 58 % being node-negative. The head and cutaneous regions (24.5 %) and tongue (20.8 %) were the most common tumor sites. Primary surgical resection and adjuvant radiation were performed in 47.2 % of cases, and concurrent chemotherapy was used in 40.7 %. Reirradiation was mainly for local or regional recurrence (88.9 %), often following salvage surgery (68.5 %), with a mean dose of 5623 Gy over 52.5 fractions. Positive surgical margins were present in 29.4 % of cases, and extracapsular spread in 59.5 %. No significant differences were found between the salvage surgery and definitive reirradiation groups except for tumor site (P = 0.022). Median follow-up was 52.6 months, with 27 deaths reported. Lymphovascular invasion was significantly correlated with overall survival (P = 0.017), while initial tumor T-stage and neck disease involvement were linked to local-regional control (P = 0.030 and P = 0.033, respectively). Reirradiation increased tracheotomy and PEG-tube dependency by 20 % (P = 0.011) and 23 % (P = 0.003), respectively. ConclusionsReirradiation is a feasible therapeutic alternative in recurrent head and neck SCC. Oncologic outcomes observed in this series compare favorably to most published reports. Complete response and perineural invasion were independent prognostic factors for survival and locoregional control. While no mortality directly associated with treatment was observed in this series, reirradiation had a significant impact in functional outcomes in terms of increased risk of tracheotomy and peg tube dependency. Further studies are required to define the role of this treatment in head and neck cancer.

Trends in the treatment of human papillomavirus-associated oropharyngeal carcinoma in Slovakia.

The optimal treatment of oropharyngeal cancer (OPC) associated with human papillomavirus (HPV) is currently a subject of clinical research. This questionnaire study investigated current trends in the treatment of HPV-associated (HPV+) OPC in Slovakia with the incorporation of deintensification of oncological treatment into routine clinical practice outside of clinical trials. The Slovak Cooperative Head and Neck Cancer Group (SCHNCG) developed a questionnaire aimed at identifying trends in the oncological treatment of HPV+ OPC intended for all radiation oncology (RO) facilities in Slovakia. Specialists in the field of RO responded to general questions about the character of their individual institutions as well as to 4 theoretical clinical scenarios (case reports) regarding the treatment of HPV+ OPC, focusing primarily on the applied dose of radiotherapy (RT), the extent of target volumes, and the type of concurrent chemotherapy (CHT). The questionnaire study involved 35 RO specialists from 14 institutions in Slovakia. Regarding primary chemoradiotherapy (CRT) in T1N1M0 HPV+ OPC, 16 respondents (45.7%) would consider de-escalation of the RT dose to <70 Gy. In the case of postoperative RT in pT1pN1M0 HPV+ OPC with negative resection margins (R0) and absent extracapsular extension (ECE), 4 physicians (11.4%) would consider de-escalation of the RT dose to <60 Gy in the tumor bed area, while the majority of the treating specialists (n=19, 54.3%) would omit concurrent CHT. In the case of primary RT in elderly patient with T2N1M0 HPV+ OPC, the same number of physicians (n=16, 45.7%) would consider de-escalation of the RT dose to <70 Gy, and 14 respondents (40.0%) would completely omit CHT. In a high-risk patient with T2N3M0 HPV+ OPC with a complete response after 3 cycles of induction chemotherapy (iCHT), none of the respondents would indicate a reduction in the RT dose to the area of the original tumor and lymphadenopathy to <60 Gy. The doses and extent of irradiated volumes in the treatment of HPV+ OPC in Slovakia vary among different institutions. The tendency to de-escalate RT doses and reduce doses of concurrent systemic therapy in Slovakia is high and there was also an observed trend to reduce the extent of radiation treatment fields.

Pelvic lymph node mapping in prostate cancer: examining the impact of PSMA PET/CT on radiotherapy decision-making in patients with node-positive disease

IntroductionProstate Specific Membrane Antigen (PSMA) imaging with Positron Emission Tomography (PET) plays a crucial role in prostate cancer management. However, there is a lack of comprehensive data on how PSMA PET/CT (Computed Tomography) influences radiotherapeutic decisions, particularly in node-positive prostate cancer cases. This study aims to address this gap by evaluating two primary objectives: (1) Mapping the regional and non-regional lymph nodes (LNs) up to the aortic bifurcation and their distribution using conventional methods with CT compared to PSMA PET/CT, and (2) assessing the impact of PSMA PET/CT findings on radiotherapeutic decisions.MethodsA retrospective analysis of 95 node-positive prostate cancer patients who underwent both CT and PSMA PET/CT imaging prior to primary radiotherapy and androgen deprivation therapy (ADT) was conducted. The analysis focused on identifying LNs in various regions including the common iliac, external iliac, internal iliac, obturator, presacral, mesorectal, inguinal, and other stations. Treatment plans were reviewed for modifications based on PSMA PET/CT findings, and statistical analysis was performed to identify predictors for exclusive nodal positivity on PSMA PET/CT scans.ResultsPSMA PET/CT identified additional positive nodes in 48% of cases, resulting in a staging shift from N0 to N1 in 29% of patients. The most frequent metastatic LNs were located in the external iliac (76 LNs; 34%), internal iliac (43 LNs; 19%), and common iliac (35 LNs; 15%) stations. In patients with nodes only detected on PSMA PET the most common nodes were in the external iliac (27, 40%), internal iliac (13, 19%), obturator (11, 15%) stations. Within the subgroup of 28 patients exclusively demonstrating PSMA PET-detected nodes, changes in radiotherapy treatment fields were implemented in 5 cases (18%), and a dose boost was applied for 23 patients (83%). However, no discernible predictors for exclusive nodal positivity on PSMA PET/CT scans emerged from the analysis.DiscussionThe study underscores the pivotal role of PSMA PET/CT compared to CT alone in accurately staging node-positive prostate cancer and guiding personalized radiotherapy strategies. The routine integration of PSMA PET/CT into diagnostic protocols is advocated to optimize treatment precision and improve patient outcomes.

Prognostic significance of hemorrhage requiring embolization in the setting of previously treated head and neck squamous cell carcinoma: Systematic review and retrospective cohort.

The management of acute hemorrhage in patients with previously treated head and neck squamous cell carcinoma (HNSCC) is challenging due to the lack of substantial evidence to guide clinical decision making. A systematic review and retrospective chart review were performed to identify patients with a history of HNSCC who underwent either primary or adjuvant radiation therapy (RT) and presented with hemorrhagic complications requiring embolization. Patient characteristics, history, presentation, and outcomes were reviewed. The systematic review included a total of 182 patients. Heterogeneity existed in outcomes reporting; 1-year overall survival approached 50%. From the retrospective chart review, 51 patients were included. Median survival time following hemorrhage was 2.2 months (range 1.2-11.4 months). Patients with malignancy at time of hemorrhage were identified as having worse survival. Acute hemorrhage in patients with a history of previously radiated HNSCC portends a high risk of mortality, with patients with active malignancy representing a worse prognostic group.

Stereotactic ablative radiotherapy for locally advanced non-small cell lung cancer: A systematic review and meta-analysis

IntroductionTo evaluate the feasibility, efficacy and safety of stereotactic ablative radiotherapy (SABR) to the primary tumor and lymph nodes in patients with locally advanced non-small cell lung cancer (LA-NSCLC) who are ineligible for or refused concomitant chemoradiation. Materials and MethodsIn accordance with the PRISMA and MOOSE guidelines, a systematic review with meta-analysis was conducted. The study included reports that assessed the outcomes of SABR treatment in patients with LA-NSCLC. Studies evaluating SBRT as a boost following primary radiotherapy were excluded. The primary outcomes measured were local control (LC) and overall survival (OS). The secondary endpoint was the incidence of severe toxicity (grades 3–5). A meta-regression analysis was performed to explore the relationship between LC, OS, and severe toxicity. The Biologically Effective Dose (BED) was analyzed as a continuous variable. Statistical significance was defined as a p-value < 0.05. ResultsA total of seven studies (3 prospective and 4 retrospective studies) involving 268 patients (SBRT to primary and lymph nodes) were included in the analysis. The pooled 1-year LC rate was 80 % (95 % CI: 63–94 %), and the factors significantly associated with LC were BEDGy10 (p = 0.005) and neoadjuvant chemotherapy (p = 0.005). The 1-year and 2-year OS rates were 74 % (95 % CI: 58–90 %) and 55 % (95 % CI: 34–76 %), respectively. Meta-regression analysis indicated a linear relationship between OS and LC, with a 0.7 % increase in OS for each 1 % improvement in LC (p = 0.005). The pooled rate of grade 3 acute toxicity was 5 % (95 % CI: 1–10 %), and the rate of grade 5 toxicity was 1.7 % (95 % CI: 0–3 %). ConclusionPromising results (LC and OS) with limited toxicity (feasibility) using SABR in LA-NSCLC warrant further research, emphasizing the need for larger, well-designed trials for further validation of the approach.

Identification and validation of a machine learning model of complete response to radiation in rectal cancer reveals immune infiltrate and TGFβ as key predictors

It is uncertain which biological features underpin the response of rectal cancer (RC) to radiotherapy. No biomarker is currently in clinical use to select patients for treatment modifications. We identified two cohorts of patients (total N=249) with RC treated with neoadjuvant radiotherapy (45Gy/25) plus fluoropyrimidine. This discovery set included 57 cases with pathological complete response (pCR) to chemoradiotherapy (23%). Pre-treatment cancer biopsies were assessed using transcriptome-wide mRNA expression and targeted DNA sequencing for copy number and driver mutations. Biological candidate and machine learning (ML) approaches were used to identify predictors of pCR to radiotherapy independent of tumour stage. Findings were assessed in 107 cases from an independent validation set (GSE87211). Three gene expression sets showed significant independent associations with pCR: Fibroblast-TGFβ Response Signature (F-TBRS) with radioresistance; and cytotoxic lymphocyte (CL) expression signature and consensus molecular subtype CMS1 with radiosensitivity. These associations were replicated in the validation cohort. In parallel, a gradient boosting machine model comprising the expression of 33 genes generated in the discovery cohort showed high performance in GSE87211 with 90% sensitivity, 86% specificity. Biological and ML signatures indicated similar mechanisms underlying radiation response, and showed better AUC and p-values than published transcriptomic signatures of radiation response in RC. RCs responding completely to chemoradiotherapy (CRT) have biological characteristics of immune response and absence of immune inhibitory TGFβ signalling. These tumours may be identified with a potential biomarker based on a 33 gene expression signature. This could help select patients likely to respond to treatment with a primary radiotherapy approach as for anal cancer. Conversely, those with predicted radioresistance may be candidates for clinical trials evaluating addition of immune-oncology agents and stromal TGFβ signalling inhibition. The Stratification in Colorectal Cancer Consortium (S:CORT) was funded by the Medical Research Council and Cancer Research UK (MR/M016587/1).

Effect of Long-Range Interaction in the Modification of Surface Layers of WC–Co Samples by a Pulsed Ion Beam

The results of modification of WC–Co samples by a pulsed beam of nitrogen ions (200–300 keV, 120 ns) with an energy density of 7–8 J/cm2 are presented. It is shown that the change in the structure occurs in the near-surface layer with a thickness of 20–30 µm, which significantly exceeds the range of ions in the target (≈0.5 µm) and the depth of propagation of the thermal front during the pulse (≈1 µm). The analysis of various mechanisms of the long-range effect is carried out: the formation of a shock wave, the generation of primary radiation defects, etc. It is shown that the long-range effect is associated with the charge exchange of ions and the formation of fast atoms. The simulation of the charge exchange of ions in the gaseous layer of desorbed molecules is performed. It was found that the probability of ion charge exchange in the processes N+ + N2 → N0 and N+ + O2 → N0 significantly exceeds 100%, which indicates that the effect of irradiation by atoms was not taken into account while calculating. In contrast to ions, when the target is irradiated with atoms, the efficiency of the formation of radiation defects is much higher.

Using a machine learning algorithm and clinical data to predict the risk factors of disease recurrence after adjuvant treatment of advanced-stage oral cavity cancer

ABSTRACT Objectives: Head-and-neck cancer is a major cancer in Taiwan. Most patients are in the advanced stage at initial diagnosis. In addition to primary surgery, adjuvant therapy, including chemotherapy and radiotherapy, is also necessary to treat these patients. We used a machine learning tool to determine the factors that may be associated with and predict treatment outcome. Materials and Methods: We retrospectively reviewed 187 patients diagnosed with advanced-stage head-and-neck cancer who received surgery and adjuvant radiotherapy with or without chemotherapy. We used eXtreme Gradient Boosting (XGBoost) – a gradient tree-based model – to analyze data. The features were extracted from the entries we recorded from the electronic health-care system and paper medical record. The patient data were categorized into training and testing datasets, with labeling according to their recurrence status within the 5-year follow-up. The primary endpoint was to predict whether the patients had recurrent disease. The risk factors were identified by analyzing the feature importance in the model. For comparison, we also used regression to perform the variate analysis to identify the risk factors. Results: The accuracy, sensitivity, and positive predictive value of the model were 57.89%, 57.14%, and 44.44%, respectively. Pathological lymph node status was the most important feature, followed by whether the patient was receiving chemotherapy. Fraction size, early termination, and interruption were the important factors related to radiotherapy and might affect treatment outcome. The area under the curve of the receiver operating characteristic curve was 0.58. The risk factors identified by XGBoost were consistent with those found by regression. Conclusion: We found that several factors were associated with treatment outcome in advanced-stage head-and-neck cancer. In future, we hope to collect the data according to the features introduced in this study and to construct a stronger model to explain and predict outcomes.

The effect of particles size of Gd2O3 on the radiation protection mechanisms of ZnO

There are two mechanisms established for increasing the radiation resistance of optical properties of micron-sized zinc oxide (mZnO) powder modified by gadolinium oxide (nGd2O3) nanoparticles by means of relaxation of the primary radiation defects (electrons and holes): — in atoms of rare-earth element gadolinium; — on Gd2O3 nanoparticles. During modification with gadolinium oxide micron-sized particles, only one (first) mechanism for radiation resistance increasing is enabled. These results are obtained by recording diffuse reflectance spectra in high vacuum in the range of 0.2–2.5 μm under radiation exposure by accelerated electrons (in situ). The established mechanisms for increasing radiation resistance refer not only to the types of powders under the study, but also to other types of oxide semiconductor powders and rare-earth elements. These mechanisms can also be extended to the photo résistance of oxide powders modified by nanoparticles and solid solutions based on them.

Towards machine learning-based quantitative hyperspectral image guidance for brain tumor resection

BackgroundComplete resection of malignant gliomas is hampered by the difficulty in distinguishing tumor cells at the infiltration zone. Fluorescence guidance with 5-ALA assists in reaching this goal. Using hyperspectral imaging, previous work characterized five fluorophores’ emission spectra in most human brain tumors.MethodsIn this paper, the effectiveness of these five spectra was explored for different tumor and tissue classification tasks in 184 patients (891 hyperspectral measurements) harboring low- (n = 30) and high-grade gliomas (n = 115), non-glial primary brain tumors (n = 19), radiation necrosis (n = 2), miscellaneous (n = 10) and metastases (n = 8). Four machine-learning models were trained to classify tumor type, grade, glioma margins, and IDH mutation.ResultsUsing random forests and multilayer perceptrons, the classifiers achieve average test accuracies of 84–87%, 96.1%, 86%, and 91% respectively. All five fluorophore abundances vary between tumor margin types and tumor grades (p < 0.01). For tissue type, at least four of the five fluorophore abundances are significantly different (p < 0.01) between all classes.ConclusionsThese results demonstrate the fluorophores’ differing abundances in different tissue classes and the value of the five fluorophores as potential optical biomarkers, opening new opportunities for intraoperative classification systems in fluorescence-guided neurosurgery.

Investigation of metal non-opaque foreign bodies of firearm origin by radiation methods

Background. The purpose is to investigate metal non-opaque foreign bodies of firearm origin. Materials and methods. Five cases of removing soft tissue foreign bodies of gunshot origin were investigated, when radiography of the limb soft tissues didn’t detect foreign bodies, but they were removed during the primary surgical wound debridement. X-ray of soft tissue gunshot wounds found no foreign bodies. To study radiographic density, foreign bodies were placed in a foam model with subsequent multislice computed tomography. For spectral analysis of metal foreign bodies, we used wavelengths unconventional for X-ray, which allowed to conduct X-ray fluorescence and X-ray structural studies. Results. Radiographic density of metal foreign bodies ranged from 989 to 2123 HU. Given the different thickness of foreign bodies, from 0.4 to 3.2 mm, the average was 1700 ± 189 HU. The foam had radiographic density of –969 HU with model dimensions of 200 × 100 × 50 mm. When examining samples of foreign bodies, it was found that they are deformed, have different thicknesses. One of the samples is light and smooth on one side, and dark and rough on the other. X-ray fluorescence results: composition on the light side (% by mass): Al — base, Mn — 0.8, Fe — 0.3, Zn — 0.1, Cr — 0.05, Ti — 0.2, corresponding to Al-Mn alloy. The dark side is an oxidized Al-Mn alloy. In the spectrum of the dark side of the sample, the Br-Kα line was detected, which indicates the participation of bromine compounds in the oxidation process. From the smooth side of the sample, the spectrum of this line is not determined. Conclusions. Non-opaque metal foreign bodies of gunshot origin are a rare phenomenon. Metal foreign bodies with low radiographic density are non-ferromagnetic, the use of modern magnetic surgical instruments will not be effective. Visualization of metal foreign bodies, which are not determined by radiography, is possible with the help of multislice computed tomography. The use of the wavelength of primary radiation, which is unconventional for X-ray spectral analysis, and original X-ray optical schemes allows for quantitative determination of the composition and structure of any metal foreign bodies.

Salvage High-Intensity Focused Ultrasound for Prostate Cancer after Radiation Failure: A Narrative Review.

For patients diagnosed with localized prostate cancer, there are multiple treatment options available. The traditional treatment modalities include radical prostatectomy and radiotherapy. Nevertheless, focal therapy, including high-intensity focused ultrasound (HIFU) and cryotherapy, has emerged as a less-invasive method in this setting. Some patients undergoing primary radiation therapy experience recurrence, but there is currently no consensus on the optimal approach for salvage treatment in such cases. The lack of robust data and randomized controlled trials comparing different whole-gland and focal salvage therapies presents a challenge in determining the ideal treatment strategy. This narrative review examines the prospective and retrospective data available on salvage HIFU following radiation therapy. Based on the literature, salvage HIFU for radio-recurrent prostate cancer has promising oncological outcomes, with an overall 5-year survival rate of around 85%, as well as incontinence rates of about 30% based on the patient's risk group, follow-up times, definitions used, and other aspects of the study. Salvage HIFU for prostate cancer proves to be an effective treatment modality for select patients with biochemical recurrence following radiotherapy.

Displacement cascade and defect-driven simulations in V-Ti-Ta-Nb high-entropy alloy

High-entropy alloys (HEA) have attracted considerable attention in the development of nuclear materials due to their excellent properties. In this study, the primary irradiation damage and long-term defect evolution of pure V, V-5Ti-5Ta conventional alloy, V-Ti-Ta MEA and V-Ti-Ta-Nb HEA were simulated by molecular dynamics (MD) to understand the irradiation resistance mechanism of these four systems. The primary irradiation damage simulation results indicate that the V-Ti-Ta MEA and V-Ti-Ta-Nb HEA exhibit a delayed thermal peak, a longer defect recombination time and a slightly higher number of final Frenkel pairs (FPs) than pure V and V-5Ti-5Ta alloy. Both primary irradiation damage and long-time defect evolution results show that V-Ti-Ta MEA and V-Ti-Ta-Nb HEA have lower defect clustering fraction, cluster size and dislocation loop size than pure V and V-5Ti-5Ta. This is because V-Ti-Ta MEA and V-Ti-Ta-Nb HEA exhibit lower dislocation loop binding energy and defect mobility compared to pure V and V-5Ti-5Ta alloy. This study investigates the reasons for the better radiation resistance of V-Ti-Ta MEA and V-Ti-Ta-Nb HEA than pure V and V-5Ti-5Ta conventional alloys.

MDB-48. A SINGLE INSTITUTION EXPERIENCE OF CIPN MEASURED BY THE PED-MTNS IN CHILDREN AND ADOLESCENTS WITH MEDULLOBLASTOMA TREATED ON A TRIAL USING SIMILAR DOSING OF VINCRISTINE AND CISPLATIN FOR ALL PATIENTS

Abstract BACKGROUND Standard treatment for medulloblastoma in patients &amp;gt;3 years of age consists of tumor resection, radiation and chemotherapy using vincristine, cisplatin, cyclophosphamide +/- CCNU. Vincristine and Cisplatin are known to cause chemotherapy induced peripheral neuropathy (CIPN). The prevalence of CIPN in children with non-CNS cancers can be measured using the pediatric-modified Total Neuropathy Score (ped-mTNS). The purpose of this observational, retrospective pilot design is twofold: to investigate the prevalence of CIPN in children with medulloblastoma receiving neurotoxic chemotherapy, and to examine the feasibility of using the ped-mTNS as a measurement tool in this population. METHODS Data was manually extracted from medical records and entered into a REDCap database for analysis. The percent of patients successfully tested and clinical inferences made from ped-mTNS testing results were used to determine feasibility and barriers to use. A total of 33 medulloblastoma patients &amp;gt;3 years of age were treated from 6/2013 - 6/2021 at Children’s Minnesota. Of those, 18 received testing using the ped-mTNS during chemotherapy treatment. RESULTS During cancer treatment, 54.5% of the cohort of patients received ped-mTNS testing. The average age of children tested was 10.26 (4.39) years with a majority being male (79%), and non-Hispanic white race/ethnicity (89%). Of the tested participants, 61.1% had more than one measurement. For those patients tested at multiple timepoints, 72.7% demonstrated worsening ped-mTNS scores while on chemotherapy treatment. Therapists recorded inferences relating to neuropathy in 88.1% of testing occurrences with questions of accuracy recorded in 31.3% of testing occurrences. Barriers to use of results included confounding impairments that may occur as a result of the primary tumor, post-surgical changes, and radiation. CONCLUSIONS Using the ped-mTNS is feasible in children and adolescents with medulloblastoma. The ped-mTNS scores indicated that children with medulloblastoma, treated with Vincristine and Cisplatin, experience worsening neuropathy while undergoing chemotherapy treatment.

Driving Factors and Numerical Simulation of Evapotranspiration of a Typical Cabbage Agroecosystem in the Shiyang River Basin, Northwest China

Two years of field experiments were conducted at the National Field Observation Experiment Station for Efficient Agricultural Water Use in the Wuwei Oasis, Gansu Province. Based on the eddy correlation system, the evapotranspiration (ET) of the cabbage agroecosystem during the growth period was obtained and the main driving factors of ET changes were determined. The Root Zone Water Quality Model 2.0 version (RZWQM2 model) was used to simulate ET during the growth period. The results showed the following: (1) The ET of cabbage during the growth period was 260. 1 ± 24.2 mm, which was basically lower than other crops planted in this area. (2) Through partial correlation analysis and principal component analysis, it can be found that environmental and physiological factors jointly drive changes in ET. The main driving factors include gross primary productivity, net radiation, and water use efficiency. (3) The RZWQM2 model can simulate the ET of the cabbage agroecosystem well, especially in simulating the total ET value and its trend. The growth period ETs were 7.3% lower than the ETm. Cabbage is an important cash crop in Northwest China, and ET is an important component of the water cycle in the agroecosystem. Determining the main driving factors of ET is of great significance for the sustainable utilization of agricultural water resources in Northwest China. Our results can provide a scientific basis for the cultivation of cabbage as a cash crop and the development of water saving agriculture.

The Use of Variance Reduction Techniques for Photon Dose Estimation in the Design of Radiotherapy Facilities at 10 and 15 MeV via Monte Carlo Simulations

In the context of designing radiotherapy facilities, typical dose estimation methods involve analytical approaches, as outlined in International Atomic Energy Agency (IAEA) Safety Reports Series No. 47 (IAEA 47). These methods are known for their ease of use and rapid calculations, but they could lead to either overestimation or underestimation of radiation doses. Hence, the integration of Monte Carlo (MC) methods is considered valuable. In this particular study, a radiotherapy facility was modeled using MCNP version 6.2, and dose calculations were conducted using analytical techniques following both IAEA 47 guidelines and MC simulations. The study focused on monoenergetic photon cone beams with energies of 10 and 15 MeV. Notably, the beam’s orientation prevented primary radiation from reaching the dose location at the entrance of the maze, allowing only scatter radiation to contribute to the tally. Given the challenges associated with obtaining reliable and accurate results through standard MCNP calculations, the investigation focused on the use of weight windows as a variance reduction technique. The findings revealed that the IAEA method tends to provide conservative results only when the same conditions were replicated in the MC simulations. In fact, approximately 50% of the final dose estimated through MC methods accounted for factors that were not considered in the analytical calculations. The primary contributor to scattering (averaging around 30%) was identified as the floor and ceiling. This study underscores the need for caution when relying solely on the analytical approach, as it may not consistently yield conservative outcomes.

Patterns of use of primary and first-line chemotherapy for recurrence among patients with cervical cancer

BackgroundLittle is known about real-world patterns of chemotherapy use in patients with cervical cancer.ObjectiveTo examine the patterns of chemotherapy use in patients with cervical cancerMethodsWe identified patients with cervical cancer...