Comparison of Fracture Behavior in Single-Edge Notched Beams Reinforced with Steel Bars or CFRP Bars.

To explore and compare the failure modes, deformation behaviors, and load-bearing capacities of single-edge notched (SEN) beams strengthened with carbon fiber-reinforced polymer (CFRP) and steel bars, static and dynamic three-point bending tests on both types of concrete beams have been carried out in this study. During the static tests, the electro-hydraulic servo machine served as a loading device to apply pressure to CFRP beams and reinforced concrete (RC) beams. During the impact experiments, different impact velocities were imparted by adjusting the drop hammer's height. Thus, information regarding crack propagation, energy absorption, and deformation was obtained. The results from the static tests showed that the RC beams predominantly experienced shear failure. In contrast, the CFRP beams primarily exhibited bending-shear failure, attributed to the relatively weaker bond strength between the bars and the concrete. Impact tests were conducted at three different velocities in this study. As the impact velocity increased, both types of concrete beams transitioned from bending failure to bending-shear failure. At the lowest velocity, the difference in energy absorption between beams reinforced with different materials was insignificant during the bending process. However, at the highest velocity, CFRP beams absorbed less energy than RC beams. The study of structures' impact failure modes and their mechanical characteristics offers valuable references for the anti-collision design and protection of structures.

Effect of loading direction and anatomical location on the ultimate tensile stress, fracture toughness, and failure patterns of knee meniscus.

BACKGROUND: Rupture of the knee menisci is a common injury that can have implications for other conditions, such as osteoarthritis. The fracture toughness of soft tissue (Jc) is a mechanical property that characterizes its resistance to tear extension. To date, Jc of the meniscus has not been quantified. METHODS: Cyclic tensile tests were conducted on meniscus samples to determine Jc and explore its characteristics. Initially, the study investigated the impact of an initial notch on the ultimate tensile stress. This allowed for an understanding of how the presence of a notch affects its structural integrity. Subsequently, Jc was measured in both the radial and circumferential directions to assess its loading direction dependency. Furthermore, the study assessed the effect of anatomical location by comparing samples collected from the femoral and tibial layers. RESULTS: Defect tolerance of the meniscus is influenced by the loading direction. In the circumferential direction, the presence of an initial notch did not affect the ultimate stress, and no crack expansion was observed. In radial samples with a notch length of 40% or more of the total width, crack propagation occurred, leading to a decrease in the ultimate stress (p< 0.01). Additionally, Jc was found to be higher in the femoral layer compared to the tibial layer (p= 0.017). CONCLUSION: The study also examined the failure patterns of the meniscus to enhance our understanding of its pathology. These insights contribute to a better comprehension of meniscus injuries and can aid in the development of more effective treatment strategies.

Patterns and Prognosis of Local Recurrence of Nasopharyngeal Carcinoma after Intensity-modulated Radiotherapy.

Objective: To investigate the patterns of local failure and prognosis in patients with locally recurrent nasopharyngeal carcinoma (rNPC) after primary intensity-modulated radiotherapy (IMRT). Methods: The data of 298 patients with locally rNPC after IMRT were retrospectively analyzed. Magnetic resonance images of the initial and recurrent tumors were reviewed and, for patients with extra-nasopharyngeal local recurrence, the gross tumor volume of local recurrence was transferred to the original IMRT plan for dosimetry analysis. Significant prognostic factors for overall survival (OS) were selected by multivariate Cox regression analysis. Results: The commonest recurrence sites were the nasopharynx (93%, 277/298) and skull base (53.7%, 160/298). Of the 21 patients with extra-nasopharyngeal recurrence (19 cases valid), 12 had in-field failures, 4 had marginal failures, and 3 had out-field failures. The ethmoid sinus (57.1%, 4/7) and nasal cavity (28.6%, 2/7) were the most frequent sites of marginal and out-field failures. After median follow-up of 37 months, the 3-year and estimated 5-year OS rates were 57.3% and 41.7%, respectively. Multivariate analysis showed that age, recurrence interval, plasma Epstein-Barr virus (EBV) DNA level, and recurrent T stage were independent prognostic factors for OS. Conclusions: Local failure after IMRT occurs most commonly in the nasopharynx and skull base. In patients with extra-nasopharyngeal recurrence, in-field failure remains the main failure pattern, and marginal and out-field failures mainly occur in the ethmoid sinus and nasal cavity. Elder age, shorter recurrence interval, detectable plasma EBV DNA, and advanced recurrent T stage are negative predictors of OS in patients with rNPC.

Numerical Study on the Impact of Locked-In Stress on Rock Failure Processes and Energy Evolutions.

Locked-in stress refers to internal stress present within rock formations that can influence the failure process of rocks under specific conditions. A simplified mechanical model is applied, drawing on elasticity and the hypothesis of locked-in stress, to explore the influence of locked-in stress on the mechanical properties of loaded rocks. An analytical solution is obtained for the stress distribution in a failure model of rocks that include locked-in stress. The findings demonstrate that the geometry and orientation of stress inclusions within the rock influence the initiation and propagation of cracks under the combined influence of locked-in stress and high-stress conditions. Moreover, the presence of locked-in stress substantially reduces the rock's capacity to withstand maximum stress, thereby increasing its susceptibility to reaching a state of failure. The increase in closure stress leads to a significant increase in the magnitude of the maximum stress drop and radial strain variation within the rock, resulting in reduced strength and a shortened life of the ageing failure of the rock. In addition, the influence of stress inclusions on energy dissipation is investigated, and a novel relationship is established between the roughness coefficient of the rock structure surface and the angle of the rock failure surface. This relationship serves to characterize the linear dynamic strength properties of rock materials containing locked-in stress. This investigation not only advances the comprehension of stress distribution patterns and the effects of locked-in stress on rock failure patterns but also facilitates a more precise portrayal of the nonlinear features of alterations in the rock stress-strain curve under the influence of confined stress. These findings provide a solid theoretical foundation for ensuring the safety of excavations in various deep engineering projects.

The chemical damage of sandstone after sulfuric acid-rock reactions with different duration times and its influence on the impact mechanical behaviour.

The low-permeability characteristic of sandstone-type uranium deposits has become the key geological bottleneck during the in-situ leaching mining, seriously restricting the development and utilization of uranium resources in China. At present, the blasting-enhanced permeability (BEP) and acidizing-enhanced permeability (AEP) are confirmed to be mainstream approaches to enhance the reservoir permeability of low-permeability sandstone-type uranium deposit (LPSUD). To clarify the synergistic effect of BEP and AEP, the acid-rock reaction and dynamic impact experiments were conducted, aiming to study the effect of chemical reactions on pore structure, dynamic mechanical properties and failure pattern of sandstone. Results show that with the increasing acid-rock reaction time, the total pore volume of samples is promoted largely and exhibits obvious chemical damage. The change of pore volume depends on the pore size, the 100-1000 nm and 1000-10000 nm pores are more susceptible to acid-rock reactions. The dynamic peak strength and the dynamic elastic modulus are decreased and the dynamic peak strain and strain rate are increased when lengthening the acid-rock reaction time, whose evolution laws can be fitted by the logistic expression, the linear expression and the exponential expression, respectively. The acid-rock reactions also have an influence on the fracture development of samples after the dynamic impact. The damaged fractures on the end faces of samples grow from the isolated short fracture, the isolated long fracture to the fracture network, and the damaged fractures on the sides of samples develop from the non-penetration fractures, penetration fractures to the multi-branch fractures. This study clarifies the physical and chemical combined damage mechanism, demonstrates the potential of reservoir stimulation by uniting the BEP and the AEP, and provides a theoretical reference for the reservoir stimulation of LPSUD.

Bond strength of metal-free polyether-ether-ketone knee prostheses compared to metal knee prostheses with bone cement: A preliminary in vitro study.

BACKGROUND: Total knee arthroplasty is the most effective treatment for advanced-stage knee arthritis, and the majority of knee prostheses are made of metal. Nevertheless, metal prostheses still have several problems. The objective of this study is to introduce new metal-free knee prostheses made of polyether-ether-ketone (PEEK) and to compare their cement bond strength with metal prostheses. METHODS: Twelve sets of knee prostheses were divided into four groups (unloaded PEEK, unloaded Metal, 10 million cycles (MC) PEEK, 10 MC Metal, N = 3 each), and then attached to composite bones using bone cement. Both the 10 MC PEEK and 10 MC Metal groups were subjected to dynamic gait simulations of 10 MC, whereas the other two sets were not. Afterwards, a pull-off strength test was performed on the femoral prostheses and a shear strength test was performed on the tibial prostheses. RESULTS: No apparent cracks were observed in the bone cement after subjecting the PEEK and Metal groups to 10 million cycles of dynamic simulation. No statistically significant differences were observed (p > .05) in the strength tests for unloaded PEEK vs. unloaded Metal, 10 MC PEEK vs.10 MC Metal in the femoral pull-off test, and for unloaded PEEK vs. unloaded Metal in the tibial shear test. The shear strength of 10 MC PEEK was significantly lower (p < .05) compared to that of 10 MC Metal. CONCLUSIONS: By comparing the force analysis of previous investigations on knee prostheses with the failure pattern observed in the PEEK knee prosthesis of this study, which replicates that of the metal prosthesis. We believe that the combination of the peek knee prosthesis with bone cement is reliable. We anticipate that metal-free PEEK knee prostheses will find application in Total Knee Arthroplasty (TKA) in the future, thereby benefiting patients.

Definitive radiotherapy in patients with clinical T1N0M0 esophageal squamous cell carcinoma: A multicenter retrospective study (KROG 21-10).

PURPOSE: To assess the failure pattern and analyze the treatment scheme of definitive radiation therapy (RT) for T1N0M0 esophageal squamous cell carcinoma (ESCC). METHODS: We performed a multi-institutional retrospective analysis in T1N0M0 ESCC patients who underwent definitive RT from 2010 to 2019. Patterns of failure were demonstrated as in-, and out-field locoregional, and distant metastasis. In the analysis, freedom-from locoregional recurrence (FFLRR) and their association with clinicopathologic factors were evaluated. Propensity score matching in cT1b patients was done. RESULTS: 168 patients were included with a median follow-up of 34.0 months, and 26 cT1a, 116 cT1b disease. The rates of 3-year all and locoregional recurrence for cT1a were 30.5% and 24.1% and those for cT1b were 27.1% and 25.9%, respectively. Among 116 cT1b patients, 69 patients received elective nodal irradiation (ENI) and 47 received involved field irradiation (IFI). After propensity score matching, the 3-year FFLRR rate was 84.5%. There was no difference between ENI and IFI in FFLRR (P = 0.831) and OS (P = 0.525). The 3-year FFLRR was 83.8% (95% Confidence interval (CI), 61.8-93.8%) in IFI group and 85.3% (95% CI, 65.1-94.3%) in ENI group. In multivariate analysis, concurrent chemotherapy use was marginally associated with FFLRR (Hazard ratio, 0.16; P = 0.064). CONCLUSION: cT1a patients who cannot receive endoscopic resection showed similar failure rates as cT1b patients, questioning the staging accuracy and raised the need for thorough treatment like chemoradiotherapy. In cT1b patients, IFI with 50 to 60 Gy and concurrent chemotherapy could be reasonable.

Failure Patterns Within Different Histological Types in Sinonasal Malignancies: Making the Complex Simple.

OBJECTIVE: To analyze the failure patterns in patients with different histological subtypes of sinonasal malignancies (SNMs). STUDY DESIGN: Retrospectively gathered data. SETTING: Academic university hospital. METHODS: Patients with SNMs treated at a tertiary referral center between January 1999 and January 2019 were included. We assessed the failure patterns within different histological subtypes. RESULTS: The study included 897 patients. The median follow-up time was 100 months. Adenoid cystic carcinoma (ACC) had a moderate risk of developing local recurrence (LR) and distant metastasis (DM). Compared with ACC, squamous cell carcinoma (SCC), adenocarcinoma (AC), soft tissue sarcoma (STS), and mucosal melanoma (MM) were classified as a high LR risk group. For DM, neuroendocrine carcinoma (NEC), STS, and MM were in the high-risk group. CONCLUSIONS: ACC had intermediate local and distant failure risks, while SCC, AC, STS, and MM were at high LR risks. NEC, STS, and MM were at high DM risk.

Impact of minimally invasive total mesoesophageal excision and minimally invasive esophagectomy on failure patterns of locally advanced esophageal squamous cell carcinoma: a matched cohort study with long-term follow-up.

BACKGROUND: The effects of minimally invasive total mesoesophageal excision (MITME) on the long-term prognosis of locally advanced esophageal squamous cell carcinoma (ESCC) remain unknown. The objective of this study was to compare the static and dynamic failure patterns of MITME and minimally invasive esophagectomy (MIE) for locally advanced ESCC. METHODS: We use propensity score matching (PSM) method to analyze the postoperative failure patterns of the two groups. Cumulative event curves were analyzed for cumulative incidence of failure between different groups, and independent prognostic factors were assessed using time-dependent multivariate analyses. The risk of dynamic failure calculated at 12-month intervals was compared between the two groups using the lifetime table. RESULTS: A total of 366 ESCC patients were studied by 1:1 PSM for T stage and TNM stage (MITME group, n = 183; MIE group, n = 183). In the matched cohort, there was significant differences between the MITME and MIE groups in the failure pattern of regional lymph node recurrence (0.5 vs 3.8%, P = 0.032) and non-tumor death (10.9 vs 31.7%, P < 0.001). The cumulative event curve found that the 5-year cumulative failure rate was lower in the MITME group than in the MIE group (3.3 vs 17.1%, P = 0.026) after 5 years of survival. In addition, multivariate Cox regression analysis showed that MIE was an independent poor prognostic factor for a high cumulative failure rate in locally advanced ESCC patients at 5 years after surgery (HR:4.110; 95% CI 1.047-16.135; P = 0.043). The dynamic risk curve showed that the MITME group had a lower risk of failure within 5 years after surgery than the MIE group. CONCLUSION: Considering that MITME can significantly improve the postoperative failure pattern and the benefit lasts for at least 5 years, it is feasible to use MITME as a treatment for locally advanced ESCC.

Failure pattern and radiotherapy exploration in malignant pleural effusion non-small cell lung cancer treated with targeted therapy.

Purpose: Actionable mutations are common in non-small cell lung cancer(NSCLC)with malignant pleural effusion(MPE)(MPE-NSCLC). The pattern of failure in MPE-NSCLC treated with targeted therapy after MPE control remains unclear. We aimed to investigate the failure pattern of such patients in a cohort study and explore the possibility of radiotherapy. Patients and methods: Computed tomography scans of 86 patients were reviewed in this study. We classified first pattern of failure after MPE control as initial disease sites only (IF), new distant sites only (NF), or IF and NF detected simultaneously (INF). Patients evaluated suitable for radiotherapy after disease progression were divided into two groups: D group without radiotherapy and RD group with radiotherapy. The Kaplan-Meier method and log-rank test were used for survival analyses. Results: Disease progression after MPE control was observed in 42 patients with complete serial imaging. Median time to any progression was 9.5 months. Rate of the IF, NF and INF were 50%, 17% and 33% for all patients,60%,0% and 40% for patients with MPE recurrence (n=10,23.8%) and 47%, 22% and 31% for patients (n=32,76.2%) without MPE recurrence, respectively. Out of 10 patients(23.8%) with MPE recurrence, 7 patients simultaneous underwent primary tumor progression and 5 MPE were cytologically confirmed in 7 patients with examination. The overall survival (OS )rates at 1, 2, 3 years for the RD group and D group were 88.2%, 50.5%, 21.7% and 80.0%, 20.3%, 0%, respectively; the corresponding MST were 26.1 months and 17.5 months, respectively (χ2 = 4.959, p =0.026). Conclusions: Our data indicates that 50% of patients with actionable mutations MPE- NSCLC after MPE control are likely to fail at their initial sites of disease and the use of radiotherapy may bring OS benefits during the course of their disease. Multicenter RCT is necessary to confirm the result in the future.

Patterns and prognosis of regional recurrence in nasopharyngeal carcinoma after intensity-modulated radiotherapy.

OBJECTIVE: We analyzed the patterns of lymph node (LN) failure and prognosis in patients with regional recurrent nasopharyngeal carcinoma (rNPC) alone after primary intensity-modulated radiotherapy (IMRT). METHODS: A total of 175 patients who were treated with IMRT between 2010 and 2015 and who experienced regional recurrence alone were included. Recurrent LNs were re-located in the initial pretreatment imaging and IMRT plan and failures were classified as in-field or out-field based on target volume delineation. All patients underwent curative salvage treatment. Independent prognostic factors for overall survival (OS) were selected by multivariate Cox analysis. RESULTS: Level IIb (49.1%, 86/175) was the most frequent recurrence site, followed by level IIa (36%), level III (18.9%), level IVa (12%), the retropharyngeal region (8%), level Va (6.9%), and the parotid region (6.9%). A total of 264 recurrent LNs were recorded: 149 (56.4%) were classified as in-field failure with a prescribed dose ≥66 Gy, 60 (22.7%) with 60 to <66 Gy, 32 (12.1%) with 50 to <60 Gy, and 23 (8.7%) as an out-field failure, which mainly occurred in the parotid region and level Ib. After a median follow-up of 52.8 months, the estimated 5-year OS rate was 66.9%. Multivariate analysis showed that age, plasma Epstein-Barr virus DNA level, extranodal extension, lower neck involvement, and parotid LN recurrence were independent prognostic factors of OS. CONCLUSIONS: In-field failure represented the main pattern of regional recurrence and out-field failure mainly occurred in the parotid gland and level Ib. Patients with regional rNPC alone had a good prognosis after salvage treatment.

Does stem profile have an impact on the failure patterns in revision total knee arthroplasty?

INTRODUCTION: Revision total knee arthroplasty (RTKA) has been increasing continuously. The results of RTKA still remain unsatisfactory. Failure patterns and risk factors in RTKA were thoroughly analyzed, with periprosthetic joint infections (PJI) and aseptic loosening remaining at the forefront of re-revision (ReRTKA) causes. While there is evidence that stem profile impacts the revisability of cemented implants, its association with the modes of RTKA failure is unknown. METHODS: 50 consecutive ReRTKA performed in a single orthopedic center during 2016-2017 were retrospectively analyzed. The cases were stratified according to age, sex, number of preexisting revisions, fixation technique, stem design and causes of re-revision. All explanted implants with conical vs. cylindrical stem profiles were compared. RESULTS: Mean age was 67 ± 11.5, and 54% were females. 72% of the cases had ≥ 3 previous revisions. 88% were full-cemented, 3% hybrid and 9% press-fit stems. 36% of the RTKA had conical, 58% cylindrical and 6% combined stem profiles. 92% of the RTKA components were removed. Removal causes were: PJI (52.2%), aseptic loosening (34.8%), implant malposition (9.8%), painful knee (1.1%) and instability (2.2%). While the overall RTKA failure patterns were equally distributed between conical and cylindrical stems, subgroup analysis of only cemented ReRTKA revealed a higher incidence of aseptic loosening within cylindrical stem profiles (46.7% vs. 25.7%, P = 0.05). CONCLUSION: Stem profile may have an impact on the process of aseptic loosening in cemented non-metaphyseal engaging RTKA, with cylindrical designs tending to worse outcomes than conical designs. Large cohort studies could provide more clarity on current observation.

Failure patterns for thymic carcinoma with completed resection and postoperative radiotherapy.

BACKGROUND AND PURPOSE: We aimed to evaluate the pattern and risk factors of disease failure in patients with thymic carcinoma after complete resection and postoperative radiotherapy (PORT). MATERIALS AND METHODS: We retrospectively analyzed 127 patients with thymic carcinoma who underwent PORT after complete resection between 2003 and 2020 in our center. Data on clinical characteristics and radiation fields were collected. Failure patterns were recorded as locoregional (disease appearing in the tumor bed or regional lymph nodes), pleural, or distant failure (including hematogenous metastasis and nonregional lymph node metastasis). RESULTS: All patients underwent tumor bed irradiation. During a median follow-up period of 64 months, disease failure was observed in 51 patients (40.2 %). The 5-year disease-free survival (DFS) and overall survival rates were 58.9 % and 85.0 %, respectively. The sequence of failure patterns was distant (n = 41, 32.3 %), pleural (n = 28, 22.0 %), and locoregional failure (n = 19, 15.0 %). Of the locoregional failure patients, failures occurred in-field in three patients (2.4 %), marginal failure in one patient (0.8 %), out-of-field failure in nine patients (7.1 %), synchronous in-field and out-of-field failures in two patients (1.6 %), synchronous marginal and out-of-field failures in two patients (1.6 %), and unknown failure fields in two patients (1.6 %). Multivariate analysis showed that Masaoka stage (hazard ratio [HR], 3.88; p = 0.000) and adjuvant chemotherapy (HR, 0.47; p = 0.015) were independent predictors of DFS. CONCLUSION: The most common failure was distant, the Masaoka stage and adjuvant chemotherapy were independent predictors of DFS, and low locoregional failure-supported tumor bed irradiation was sufficient for patients with thymic carcinoma after complete resection.

Analysis of failure patterns and survival after SBRT for 147 cases of T 1-2N 0M 0 stage non-small cell lung cancer / 中华放射肿瘤学杂志

Objective:To analyze the failure patterns and survival after stereotactic body radiotherapy (SBRT) in patients with T 1-2N 0M 0 non-small cell lung carcinoma (NSCLC). Methods:Clinical data of early-stage NSCLC patients who received SBRT at Zhejiang Cancer Hospital from January 2012 to September 2018 were retrospectively analyzed. The primary observed endpoint was the pattern of disease progression, which was divided into intra-field recurrence, regional lymph node recurrence and distant metastasis. Overall survival (OS) and progression-free survival (PFS) were calculated by Kaplan-Meier method. Univariate analysis was conducted by log-rank test, and multivariate analysis was performed by Cox's model.Results:A total of 147 patients with 156 lesions were included. The median follow-up time was 44.0 months (16.5-95.5 months). A total of 57 patients (38.8%) progressed: 14 patients (24.5%) had recurrence with the 1-, 3-, and 5-year local recurrence rates of 2.0%, 10.9%, and 14.3%, respectively; 36 patients (63.2%) had Distant metastasis with the 1-, 3- and 5-year distant metastasis rates of 12.2%, 22.4% and 28.6%, respectively; and 7 patients (12.3%) had recurrence complicated with distant metastasis. The 3-, 5- and 7-year OS rates were 80.5%, 64.2% and 49.9% for all patients, respectively. The median OS was 78.4 months. The 3-, 5- and 7-year PFS rates were 64.8%,49.5% and 41.5%, with a median PFS of 57.9 months (95% CI: 42.3-73.5 months). Univariate and multivariate analyses showed that biologically equivalent dose and age were the factors affecting the efficacy of SBRT (both P<0.05). Conclusion:Distant metastasis is the main failure pattern in patients with T 1-2N 0M 0 NSCLC after SBRT. High-risk population should be selected for further systematic treatment to improve the efficacy.

Patterns of Failure After Minimally Invasive Esophagectomy and Evaluation of Value of Adjuvant Therapy for Esophageal Cancer / 肿瘤防治研究

The current recommendation for postoperative radiotherapy for esophageal cancer in China is mainly based on the data of incomplete two-field dissection of open left thoracotomy. At present, the type of surgery for esophageal cancer gradually transitions from open left thoracotomy to open right thoracotomy and from open esophagectomy to minimally invasive esophagectomy (MIE). Patients with early-stage esophageal cancer are selected as candidates for MIE. MIE is less invasive than open esophagectomy, and the right thoracic approach is conducive to more thorough lymph node dissection. However, few data and related studies are available on the patterns of failure after MIE in esophageal cancer, and guiding an adjuvant therapy is difficult. The feasibility of an adjuvant therapy for selective high-risk patients and the optimized treatment after MIE remains to be explored in clinical practice. In this regard, this article aims to review the safety of MIE, long-term survival outcomes, postoperative recurrence patterns, and recurrence rates of patients to discuss the value of postoperative adjuvant therapy and guide clinical treatment.

Treatment outcomes of 156 patients with cervical esophageal cancers treated with definitive radiation therapy- A single-institution experience of a rare cancer.

Purpose: Esophageal cancer is the most prevalent malignant tumor. The incidence of cervical esophageal cancer is low and there are insufficient data on the efficacy of radical radiotherapy. The purpose of this study was to clarify the efficacy with radical IFI radiotherapy, to analyze the pattern of initial lymph node metastasis and recurrence under the new lymph node zoning of esophageal cancer. Methods: We reviewed cervical esophageal cancer treated with radical radiotherapy. The inclusion criteria were diagnosis of esophageal cancer by pathology; receiving radical radiotherapy or chemoradiotherapy; tumor location in accordance with definition of cervical esophageal cancer. Three dimensional radiotherapy was used. The target area was IFI. Results: 156 patients entered the final analysis. The proportion of no failure was 42.31%, local esophageal failure was 30.13%, in-field lymph node metastasis was 10.26%, out-field lymph node metastasis was 1.28% and distant organ metastasis was 23.72%, second primary tumor was 2.56%. The median OS and DFS was 49.0 months (35.27-62.73) and 31.0 months (14.47-47.53). The results of initial LN metastasis pattern analysis showed the supraclavicular and upper mediastinum were the main sites of cervical esophageal cancer metastasis. In patients with recurrent LN, the results showed that the cervical, supraclavicle, upper mediastinum and abdomen were the main sites of recurrence. Conclusion: Our study is a retrospective study of a large sample of radical radiotherapy for cervical esophageal cancer. Failure in irradiation field is the main failure pattern. Concurrent radiotherapy and chemotherapy under IFI radiation is a considerable treatment option for cervical esophageal cancer.

Experimental Investigation of Shale Tensile Failure under Thermally Conditioned Linear Fracturing Fluid (LFF) System and Reservoir Temperature Controlled Conditions.

Linear fracturing fluid (LFF) provides viscosity driven benefits of proppant suspensibility and fluid loss control, and with the use of a breaker agent, flowback recovery can be greatly enhanced. Shale tensile strength is critical in the prediction of fracture initiation and propagation, but its behavior under the interaction with LFF at reservoir temperature conditions remains poorly understood. This necessitated an in-depth investigation into the tensile strengths of Eagle Ford and Wolfcamp shales under thermally conditioned LFF and reservoir temperature controlled conditions. Brazilian Indirect Tensile Strength (BITS) testing was carried out for the quantitative evaluation of shale tensile strength, followed by extensive failure pattern classifications and surface crack length analysis. The thermally conditioned LFF saturation of shale samples led to average tensile strength (ATS) increases ranging from 26.33-51.33% for Wolfcamp. Then, for the Eagle Ford samples, ATS increases of 3.94 and 6.79% and decreases of 3.13 and 15.35% were recorded. The exposure of the samples to the temperature condition of 90 °C resulted in ATS increases of 24.46 and 33.78% for Eagle Ford and Wolfcamp shales, respectively. Then, for samples exposed to 220 °C, ATS decreases of 6.11 and 5.32% were respectively recorded for Eagle Ford and Wolfcamp shales. The experimental results of this research will facilitate models' development towards tensile strength predictions and failure pattern analysis and quantifications in the LFF driven hydraulic fracturing of shale gas reservoirs.

Overview of adjuvant radiotherapy on survival, failure pattern and toxicity in stage I to II endometrial carcinoma: a long-term multi-institutional analysis in China.

BACKGROUND: This research aimed to provide an overview of the impact of adjuvant vaginal brachytherapy (VBT) and external beam pelvic radiotherapy (EBRT) with or without VBT on survival in stage I to II EC patients in China from a long-term multi-institutional analysis. METHODS: We retrospectively analyzed stage I to II EC patients from 13 institutions treated between 2003 and 2015. All patients underwent surgical staging and received adjuvant RT. Patients were divided into groups of low-risk (LR), intermediate-risk (IR), high-intermediate-risk (HIR) and high-risk (HR). Survival statistics, failure pattern, and toxicity of different radiation modalities in different risk groups were analyzed. RESULTS: A total of 1048 patients were included. HR disease represented 27.6%, HIR 17.7%, IR 27.7% and LR 27.1%, respectively. Endometrioid adenocarcinoma (EAC) and non-endometrioid carcinoma (NEC) accounted for 92.8 and 7.2%. A total of 474 patients received VBT alone and 574 patients received EBRT with or without VBT. As for EAC patients, the 5-year overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) rate was: 94.6, 90.4, 93.0 and 91.6%, respectively. For LR patients, EBRT (with or without VBT) seemed to be a risk factor. With the higher risk category, the survival benefit of EBRT gradually became remarkable. EBRT (with or without VBT) significantly increased DFS, LRFS and DMFS compared to VBT alone in the HR group (p < 0.05). Distant metastasis was the main failure pattern for all risk groups. As for NEC patients, the 5-year OS, DFS, LRFS and DMFS rate was: 93.4, 87.2, 91.7 and 89.3%, respectively. As for toxicity, EBRT (with or without VBT) significantly increased the incidence of grade 1-2 gastrointestinal, urinary, and hematological toxicity. CONCLUSIONS: For stage I to II EC patients, EAC accounted for the majority and had better prognosis than NEC. For EAC patients, VBT alone resulted in comparable survival to EBRT in the LR, IR and HIR groups, while EBRT significantly increased survival in the HR group. EBRT had higher rate of toxicity than VBT.

A matched cohort study of the failure pattern after laparoscopic and open gastrectomy for locally advanced gastric cancer: does the operative approach matter?

BACKGROUND: Due to lacking evidence for confirming the efficacy of performing laparoscopic surgery for locally advanced gastric cancer (LAGC). Therefore, this study aimed to compare the static and dynamic failure patterns after laparoscopic gastrectomy (LG) and open gastrectomy (OG) in LAGC. METHODS: A total of 1792 LAGC patients who underwent radical resection between January 2010 and January 2017 were divided into the LG group (n = 1557) and the OG group (n = 235). Propensity score matching was performed to balance the two groups. Dynamic hazard rates of failure were calculated using the hazard function. Early and late failure were defined as failure occurring before and after 2 years since surgery, respectively. RESULTS: A total of 1175 patients with LAGC were included after matching (LG group, n = 940; OG, n = 235). The failure rate of the whole cohort was 43.2% (508/1175), accounting for 41.4% (389/940) and 50.6% (119/235) in the LG and OG groups, respectively. Although the two groups showed no significant differences in failure rate for any failure type, landmark analysis showed a lower early distant recurrence rate in the stage IIa-IIIb subgroup of the LG group (OG versus LG: 30.3% versus 21.1%, P = 0.004). The dynamic hazard rate peaked at 9.4 months (peak rate = 0.0186) before gradually declining. In stage IIa-IIIb patients, the hazard rate of the OG group remained significantly higher than that of the LG group within the first 2 years in terms of distant recurrence (peak rate: OG versus LG, 0.0091 versus 0.0055). CONCLUSION: Given the differences in early failure between LG and OG, more intensive surveillance for distant recurrence within the first 2 years should be considered for patients with stage IIa-IIIb after OG.

Local control and failure patterns after intensity modulated radiotherapy with reduced target volume delineation after induction chemotherapy for patients with T4 nasopharyngeal carcinoma.

BACKGROUND: The delineation of target volume after induction chemotherapy(IC) for nasopharyngeal carcinoma(NPC) is currently controversial. In this study, we aimed to analyze the long-term local control(LC) and failure patterns of T4 NPC treated with reduced target volume radiotherapy after IC. METHODS: From September 2007 to January 2013, 145 patients with T4 NPC were retrospectively reviewed. All patients received at least 1 cycle of IC followed by intensity modulated radiotherapy(IMRT). The gross tumor volume(GTV) was delineated according to the post-IC images for intracavity tumors and lymph nodes. The LC and overall survival (OS) rates were calculated using the Kaplan-Meier method. The location and extent of local failures were transferred to the pretreatment planning computed tomography (CT) for dosimetric analysis. RESULTS: With a median follow-up time of 95 months (range, 16-142 months), 23 local failures were found. The estimated 10-year LC and OS rates were 81.1%and 54.8% respectively. Among the 20 local failures with available diagnostic images, 18(90%) occurred within the 95% isodose lines and were considered in-field failures and 2(10%) were marginal. There was no outside-field failure. CONCLUSIONS: In-field failure was the major pattern of local failure for T4 NPC. IMRT with reduced target volume after IC seems to be feasible. Further researches exploring optimal volume and radiation dose for local advanced NPC in the era of IC are warranted.