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Objective:To evaluate the usability of Gafchromic HD-V2 film for dose dosimetry in the ultra-high dose-rate (UD) electron beam from a modified medical linac, and to investigate the response between the energy and dose-rate dependence to the film.Methods:The HD-V2 film was utilized to measure the average dose-rate of the UD electron beam. The measured result was compared with those by advanced Markus chamber and alanine pellets. And characteristics of the UD electron beam were also measured by HD-V2 film. Energy dependence of HD-V2 film at three beam energies (6 MV X-ray, 9 MeV and 16 MeV electron beam) was investigated by obtaining and comparing the calibration curves based on the clinical linear accelerator in the dose range of 10-300 Gy. The dose-rate dependence of HD-V2 film was also studied by varying the dose rate among 0.03 Gy/s, 0.06 Gy/s and 0.1 Gy/s, and range of 100-200 Gy/s.Results:The measured average maximum dose-rate of 9 MeV UD electron beam at source skin distance (SSD) 100 cm was approximately 121 Gy/s using HD-V2 film, consistent with the results by advanced Markus chamber and alanine pellets. The measured percentage depth dose (PDD) curve parameters of the UD electron beam were similar to the conventional 9 MeV beam. The off-axis dose distribution of the UD electron beam showed the highest central axis, and the dose was gradually decreased with the increase of off-axis distance. The energy dependence of HD-V2 film had no dependency of 6 MV and 9, 16 MeV while measuring the dose in the range from 20 to 300 Gy. The HD-V2 film had no significant dose-rate dependency at the dose rate of 0.03 Gy/s, 0.06 Gy/s and 0.1 Gy/s for the clinical linear accelerator. Likewise, there was also no dose-rate dependence in the range 100-200 Gy/s in the modified machine.Conclusion:HD-V2 film is suitable for measuring ultra-high dose rate electron beam, independent of energy and dose rate.
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Objective:To compare the effects on DNA strand break induced by ultra-high dose rate (FLASH) electron beam and conventional irradiation, and investigate whether FLASH effect was correlated with a reduction of radiation response.Methods:Aqueous pBR322 plasmid was treated with FLASH (125 Gy/s) and conventional irradiation (0.05 Gy/s) under physioxia (4% O 2) and normoxia (21% O 2). Open circle DNA and linear DNA were detected by agarose gel electrophoresis, and the plasmid DNA damage was quantified with an established mathematical model to calculate the relative biological effect (RBE) of DNA damage. In some experiments, Samwirin A (SW) was applied to scavenge free radicals generated by ionizing radiation. Results:Under physioxia, the yields of DNA strand breakage induced by both FLASH and conventional irradiation had a dose-dependent manner. FLASH irradiation could significantly decrease radiation-induced linear DNA compared with conventional irradiation ( t=5.28, 5.79, 7.01, 7.66, P<0.05). However, when the aqueous plasmid was pretreated with SW, there was no difference of DNA strand breakage between FLASH and conventional irradiation ( P>0.05). Both of the yields of open circle DNA and linear DNA had no difference caused by FLASH and conventional radiotherapy at normoxia, but were significantly higher than those under physioxia. In addition, the yields of linear DNA and open circle DNA induced by FLASH irradiation per Gy were (2.78±0.03) and (1.85±0.17) times higher than those of conventional irradiation, respectively. Conclusions:FLASH irradiation attenuated radiation-induced DNA damage since a low production yield of free radical in comparison with conventional irradiation, and hence the FLASH effect was correlated with oxygen content.
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Objective:To investigate the prognostic value of metabolic parameters of 18F-fluorodeoxyglucose ( 18F-FDG) positron emission computed tomography/computed tomography(PET/CT) in advanced non-small cell lung cancer(NSCLC) treated with first-line immune checkpoint inhibitor (ICI) combined with chemotherapy. Methods:A retrospective study was conducted to evaluate patients with advanced NSCLC who underwent baseline PET/CT before treatment at the Affiliated Cancer Hospital of Zhengzhou University from 2019 to 2021. Receiver operating characteristic (ROC) curve analysis was used to determine the cut-offs for metabolic parameters of PET/CT, including total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), and maximum standard uptake value (SUV max). Kaplan-Meier method, Log-rank test, and Cox regression model were used to calculate the overall survival (OS) and the progression-free survival(PFS). Results:A total of 44 patients were enrolled. Univariate analysis showed that the factors influencing PFS were TMTV and the number of metastatic sites ( χ2=4.19, 11.28, P<0.05) and the factors influencing OS were TMTV and TLG ( χ2=14.96, 6.05, P<0.05). Multivariate analysis suggested that number of metastatic sites was an independent prognostic marker for PFS ( P=0.011) and TMTV was an independent prognostic marker for OS ( P=0.038). Conclusions:TMTV is a prognostic indicator of OS while the number of metastatic sites is a prognostic indicator of PFS in advanced NSCLC patients who received first-line ICI combined with chemotherapy, but further prospective studies are needed.
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Objective: Single-cell RNA sequencing (scRNA-seq) was used to analyze the developing mouse molars, in order to construct a spatiotemporal development atlas of pulp cells, and further to reveal the developmental process and regulatory mechanism of tooth development. Methods: Ten mandibular first molars from C57BL/6 mice in postnatal day (PN) 0 and 3 were respectively dissected and digested to obtain single-cell suspensions. scRNA-seq was performed on 10× Genomics platform. PN 7 mouse molar scRNA-seq data were obtained from our previous study. PN 0, 3, and 7 scRNA-seq data were integrated for following analysis. The initial quality control, mapping and single cell expression matrix construction were performed by Cell Ranger. Quality control, standardization, dimensional reduction and cluster analysis were performed by using Seurat. Monocle was used to generate the pseudotime trajectory. Scillus was used to perform gene ontology analysis. In order to detect the spatiotemporal change of different population of pulp cells, the marker genes of each cluster were demonstrated by RNAscope in situ hybridization. Results: There were twenty-six cell clusters within mouse molars, which were identified as eight different cell types, including dental pulp cells, dental follicle cells, epithelial cells, immune cells, endothelial cells, perivascular cells, glial cells and erythrocytes. We further re-clustered and analyzed dental pulp cells. Cluster 0 were mature pulp cells, which located at the upper portion of crown. The main functions of cluster 0 were osteogenesis and extracellular structure organization. Cluster 1 were apical papilla cells, which located at the apical part of roots, whose main functions were extracellular structure organization and organ development. Cluster 2 were cycling cells, which were actively proliferated, resided in the lower portion of the crown. Cluster 3 and 4 were preodontoblasts and odontoblasts, respectively. Their functions were closely related to biomineralization. The proportion of mature pulp cells increased with the development process, while the proportion of cycling cells and odontoblast lineage decreased. According to the expression pattern of marker genes of each cluster, we constructed a cell atlas of dental pulp. Pseudotime trajectory analysis found there were two development trajectories within dental pulp. They both started from SPARC related modular calcium binding 2 (Smoc2)+ dental papilla cells, then went through DNA topoisomerase Ⅱ alpha (Top2a)+ cycling cells, and finally divided into coxsackie virus and adenovirus receptor (Cxadr)+ mature pulp cells or dentin sialophosphoprotein (Dspp)+ odontoblasts two lineages. Conclusions: scRNA-seq could fully discover the intercellular heterogeneity of cells on transcriptome level, which provides a powerful tool to study the process and regulatory mechanism of organ development.
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Objective:To analyze the failure patterns and influencing factors of stereotactic ablative radiotherapy (SABR) for early-stage non-small cell lung cancer (ES-NSCLC).Methods:113 cases of ES-NSCLC treated with SABR from 2012 to 2020 in our hospital were retrospectively analyzed. The failure patterns, recurrence time, recurrence site and influencing factors were analyzed. Kaplan-Meier method was used to calculate the local recurrence rate, regional lymph node recurrence rate and distant metastasis rate. Univariate analysis was performed by Log-rank test, and multivariate analysis was performed by Cox model.Results:The median follow-up time was 58 months (range: 6-108 months), and a total of 45 patients (39.8%) recurred. The median recurrence time was 36 months. Distant metastasis (DM) occurred in 31 patients (27.4%) and DM alone in 24 patients (21.2%). Local recurrence (LR) was developed in 12 patients (10.6%) and LR alone in 7(6.2%). Regional lymph node recurrence (RR) occurred in 11 patients (9.7%) and RR alone in 6 patients (5.3%). LR combined with RR was observed in 1 case (0.9%), LR combined with DM in 3(2.7%), LR combined with RR and DM in 1(0.9%), and RR combined with DM in 3(2.7%). The 1-, 2-, 3-, 4-and 5-year recurrence rates were 5.4%, 16.6%, 27.5%, 44% and 51.2%, respectively. Univariate and multivariate analyses suggested that EGFR mutation was an influencing factor of high recurrence rate.Conclusion:ES-NSCLC patients treated with SABR alone have a high recurrence rate, and DM is the most common mode of failure. Follow-up consolidation therapy is recommended, especially for EGFR mutation-positive NSCLC patients.
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Objective:To propose an automatic planning approach for Eclipse15.6 planning system based on Eclipse scripting application programming interface (ESAPI) and evaluate its clinical application.Methods:20 patients with nasopharyngeal carcinoma and 20 cases of rectal cancer were selected in the clinical planning. The developed automatic planning script SmartPlan and RapidPlan were used for automatic planning and dosimetric parameters were compared with manual planning. The differences were compared between two groups by using Wilcoxon signed rank test. Results:The dosimetric results of automatic and manual plans could meet clinical requirements. There was no significant difference in target coverage in nasopharyngeal carcinoma planning between two groups ( P>0.05), and automatic plans were superior to manual plans in organs at risk sparing ( P<0.05). Except for the homogeneity index of PTV and the maximum dose of bowel in rectal cancer plans, the other dosimetric parameters of the automatic plans were better than those of the manual plans (all P<0.05). Conclusions:Compared with the manual plans, the automatic plans have the same or similar target coverage, similar or better protection of organs at risk, and more convenient implementation. The developed SmartPlan based on ESAPI has clinical feasibility and effectiveness.
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Objective:To investigate the feasibility of transforming conventional medical accelerator to achieve ultra-high dose rate required to achieve Flash radiotherapy (Flash-RT), and to understand the physical properties of the Flash-RT beam.Methods:By transforming the Varian 23CX medical accelerator, the radiation average dose rate at the isocenter was not less than 40 Gy/s. The relevant physical measurement scheme was designed to accurately measure the actual radiation dose rate of different source skin distance (SSD) conditions, the percent depth dose (PDD) curve and the off-axis dose distribution of the beam.Results:The average dose rate of 9 MeV electron beam after the transformation was measured using the HD-V2 type film, the average dose rate of 3 s was 97.9 Gy/s, and the average dose rate of 6 s was 99.27 Gy/s. When the SSD was 100 cm, 80 cm and 60 cm, the average dose rate of 9 MeV electron beam after the transformation was 99.3 Gy/s, 168 Gy/s and 297.5 Gy/s, respectively. After the transformation, the R100 of the 9 MeV beam was 2.2 cm underwater, R50 was 3.87 cm underwater, the electron range Rp was 4.58 cm, and the maximum possible energy Ep,0 on the phantom surface was 9.28 MeV. These parameters were slightly higher than those of the conventional 9 MeV beam, manifested with slight increase in the surface dose and widening high dose flat area. The overall deposit dose distribution exhibited the highest central axis and the increase in dose declines from the axis distance. Under the condition that the field size was 20 cm×20 cm and the SSD was 100 cm, the FWHM of the vertical and horizontal off-axis dose distribution curves were 16.6 cm and 16.4 cm, respectively. Conclusion:By transforming conventional medical accelerator, the average dose rate of the beam at the isocycle meets the requirement of Flash-RT, and the average dose rate under the condition of 60 cm SSD is much higher than the requirement of at least 40 Gy/s for Flash-RT.
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Objective:To analyze the clinical efficacy of different treatment modalities and prognostic factors of patients with Masaoka-Koga stage Ⅲ thymoma.Methods:Clinical data of patients diagnosed with Masaoka-Koga stage Ⅲ thymoma admitted to Affiliated Cancer Hospital of Zhengzhou University from January 2000 to December 2018 were analyzed retrospectively. A total of 133 patients had complete treatment and follow-up data. Kaplan-Meier method was used to calculate the cumulative survival rate, log-rank method was used to compare the survival between two groups, and Cox regression model was used for multivariate analysis.Results:The median follow-up time was 50 months (3-221 months). The median overall survival (OS) was 51 (3-221) months, and the median disease-free survival (DFS) was 45 (2-221) months. The survival rate in the radical surgery group was better than that in the palliative surgery group. The 5- and 10-year OS rates in radical surgery group were 88.2% and 74.4% respectively, while in palliative surgery group were 51.8% and 32.4% respectively ( P<0.001). The 5- and 10-year DFS rates in radical surgery group were 72.2% and 45.5%, respectively, while in palliative surgery group were 32.3% and 16.1% respectively ( P=0.001). The OS in the surgery combined with radiotherapy group was better than that in the surgery alone group. The 5- and 10-year OS rates in the radical surgery group were 82.8% and 64.2% respectively, while in the palliative surgery group were 55.8% and 50.2% ( P=0.033). There was no significant difference in DFS between two groups ( P=0.176). Multivariate analysis showed that age < 50 years old ( HR=0.264, P=0.001), radical resection ( HR=0.134, P<0.001), surgery combined with radiotherapy ( HR=2.778, P=0.009) were independently associated with better OS. Age < 50 years old ( HR=0.550, P=0.046), radical resection ( HR=0.555, P=0.042), and invasion of single organ ( HR=0.111, P=0.003) were independently associated with better DFS. Conclusions:OS and DFS in patients undergoing radical surgery are significantly better than those in their counterparts treated with palliative surgery, which is the most important factor affecting prognosis. Surgery combined with radiotherapy yields better OS. It is necessary to design a rigorous and reasonable multicenter prospective study to evaluate the efficacy of various treatment modalities and prognostic factors.
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Esophageal squamous cell carcinoma is one of the most common malignant tumors in China. Neoadjuvant chemoradiotherapy combined with surgery significantly improved the survival rate of locally advanced operable esophageal squamous cell carcinoma, but approximately half of the patients had poor or no efficacy. To accurately predict the efficacy of neoadjuvant chemoradiotherapy in patients with esophageal squamous cell carcinoma and select the dominant population of neoadjuvant chemoradiotherapy, many studies on biomarkers have emerged, which have promoted the progress of neoadjuvant therapy for esophageal squamous cell carcinoma to some extent. In this article, the studies on biomarkers predicting the efficacy of neoadjuvant chemoradiotherapy in esophageal squamous cell carcinoma were reviewed.
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In recent years, the application of immune checkpoint inhibitors (PD-1/PD-L1/CTLA-4, etc.) in the treatment of non-small cell lung cancer (NSCLC) has developed rapidly. However, the response rate of immune checkpoint inhibitors alone is as low as 15%-30%. There are still many problems in clinical practice, such as limited benefit population, lack of effective biomarkers and treatment resistance, etc. Compared with conventional fractionated radiotherapy, stereotactic body radiation therapy (SBRT) has the characteristics of higher single dose, less irradiation times and stronger immune activation ability. It has shown good anti-tumor effect in patients with advanced NSCLC oligometastasis. The combination of immune checkpoint inhibitors and SBRT is the development trend of tumor therapy. Preclinical and clinical studies show that SBRT can enhance the efficacy of immunotherapy in patients with NSCLC. In the initial study, single-lesion SBRT was first recommended to reduce potential toxicity. However, more and more studies have confirmed the feasibility and necessity of multi-lesion SBRT. In this review, we not only elucidated the mechanism and the latest progress upon combined use of SBRT and immune checkpoint inhibitors in advanced NSCLC oligometastasis, but also explored the basic and clinical research of multi-lesion SBRT combined with immunotherapy, aiming to guide clinical practice.
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Objective:To analyze the data of ultra-high dose rate (FLASH) radiotherapy in GEO (Gene Expression Omnibus) database by bioinformatics method, in order to find the hub genes involved in flash radiotherapy induced acute T-lymphoblastic leukemia.Methods:The gene expression profiles of malignant tumors receiving FLASH radiotherapy were downloaded from GEO database. The R software was used to screen the differential expressed genes (DEGs) and analyze their biological functions and signal pathways. The protein-protein interaction (PPI) network of DEGs was analyzed by online tool of STRING, and Hub genes were screened by Cytoscape plug-in. The expressions of screened Hub genes in acute T lymphoblastic leukemia were identified with TCGA (The Cancer Genome Atlas) and GTEx (Genotype-Tissue Expression) database.Results:Based on the analysis of GSE100718 microarray dataset of GEO database, a total of 12 800 genes were found to be associated with radiosensitivity of acute T lymphoblastic leukemia, of which 61 significantly altered DEGs were selected for further analysis. It was found that these genes were involved in the biological processes of metabolism, stress response, and immune response through the pathways of oxidative phosphorylation, unfolded protein response, fatty acid metabolism, and so on. PPI analysis indicated that HSPA5 and SCD belonged to the Hub genes involved in the regulation of FLASH radiosensitivity, and they were significantly highly expressed in acute T lymphoblastic leukemia combined with TRD/LMO2-fusion gene.Conclusions:Through bioinformatics analysis, the Hub genes involved in regulating the sensitivity of FLASH radiotherapy and conventional radiotherapy can be effectively screened, and thus the gene expression profiles can be used to guide the stratification of cancer patients to achieve a precise radiotherapy.
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Objective:To investigate the relationship between lung immune prognostic index (LIPI) and the prognosis of locally advanced non-small cell lung cancer (LA-NSCLC) treated with radiochemotherapy.Methods:A retrospective analysis was conducted for the clinical data of LA-NSCLC patients who received radiochemotherapy in the Affiliated Cancer Hospital of Zhengzhou University from 2013 to 2019. According to the hematologic test result of the derived neutrophil-to-lymphocyte ratio (dNLR) and the lactate dehydrogenase (LDH), the patients were divided into three groups according to their LIPI scores, namely the good-LIPI group with dNLR ≤ 3 and LDH ≤ upper limit of normal (ULN), moderate-LIPI group with dNLR >3 or LDH > ULN, and poor-LIPI group with dNLR >3 and LDH > ULN. Moreover, the overall survival (OS) and the progression-free survival (PFS) were calculated using the Kaplan-Meier method, the Log-rank test, and the Cox regression model.Results:A total of 238 patients were enrolled, and their median follow-up time was 37.1 months, median PFS 16.1 months, and median OS 30.6 months. The OS and PFS of the poor-LIPI group were significantly worse than those of the good- and moderate-LIPI groups ( χ2= 9.04, 2.88, P<0.05). The univariate analysis showed that the factors influencing OS included gender, pathological type, epidermal growth factor receptor (EGFR) mutations, and LIPI ( χ2=6.10, 13.66, 10.58, 9.04, P<0.05), and the PFS was only affected by the LIPI ( χ2=2.88, P = 0.03). Multivariate analysis suggested that EGFR mutations and LIPI were independent prognostic markers for OS ( HR = 1.31, 1.36; 95% CI: 1.03-1.67, 1.05-1.76; P<0.05). Conclusions:The LIPI is a potential prognostic indicator of radiochemotherapy in LA-NSCLC, and this result should be further confirmed by prospective studies.
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Objective To investigate the correlation between cyclin G1 expression and the efficacy of radiotherapy on HCC. Methods The expression of cyclin G1 in biopsy specimens of 68 patients who received radiotherapy was detected by immunochemistry. The correlation between cyclin G1 expression and clinicopathological characteristics was analyzed by chi-square test. The correlation between cyclin G1 expression and OS or PFS was evaluated by Kaplan-Meier analysis. Univariate and multivariate analyses were used for the relation between clinicopathological characteristics and OS or PFS. Results The expression of cyclin G1 was related to portal vein tumor embolus, clinical stage and alpha fetoprotein. Survival analysis showed that the OS and PFS of patients with low expression of cyclin G1 were significantly higher than those with high cyclin G1 expression (P < 0.05). Multivariate analysis showed that cyclin G1 was an independent risk factor for DFS of patients with HCC. Conclusion High expression of cyclin G1 is an adverse prognostic factor for HCC patients who received radiotherapy.
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As a method for local treatment, radiotherapy plays a key role in the management of tumors. In the past few decades, great progress has been made in radiotherapy technology, with improvements in conformity, homogeneity, and radiotherapy efficiency, and the results are encouraging. Nevertheless, the maximum tolerated dose of normal tissue has limited the further increase in radiotherapy dose in the tumor area. If radiation-induced toxicities can be reduced, a higher radiotherapy dose can be delivered to tumor tissue, so as to achieve a better treatment response. In recent years, the unique FLASH effect of ultra-high-dose-rate radiotherapy (FLASH-RT) is capable of maintaining a consistent tumor response whilst reducing radiation-induced toxicities in normal tissue, and therefore, FLASH-RT has become a research hotspot in the field of radiotherapy across the world. At present, some scholars tend to explain the FLASH effect using the theory of acute oxygen depletion, but the protective effect of FLASH-RT on normal tissue remains to be clarified. In addition, preliminary clinical studies have been conducted for FLASH-RT, and the results are promising. Based on existing evidence, this article elaborates on the research advances in FLASH-RT in the treatment of malignant tumor, so as to provide a reference for the translation and application of this new technique.
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Objective:To explore a new technology that can protect the lungs and heart better by utilizing the dose distribution attributes of the half-field and the characteristics of the VMAT (volumetric modulated arc therapy) technology.Methods:A three-dimensional water tank was used to measure the dose of symmetrical field and half field edge and analyze them comparatively. A total of 50 patients with left breast cancer receiving the postoperative radiotherapy were selected. Among them, 25 patients were performed conserving surgery and 25 patients were performed radical mastectomy. After the operation, all the patients received the prescription dose of 50 Gy in 25 fractions. Based on the Eclipse system, the symmetrical field continuous arc VMAT technology and the semi-field segmented arc VMAT technology were used to design the plan. Besides, the dose suitability data and the treatment efficiency of target areas and organs at risk were compared and analyzed.Results:The radiation size of half-field did not increase with the increased depth in the water mode. The symmetric field gradually enlarged due to the angle of tensor factor, increased to about 2 cm at the depth of 30 cm, and the delivery dose in the half-field was lower than that in the symmetric field. The closer the field edge is, the more obvious it is. Compared with the symmetric field continuous arc plan, the half-field segmental arc VMAT plan significantly improved the delivery dose of the lungs and heart ( t=-4.11, -4.42, P=0.00), in which the mean values of V5, V30, and Dmean for the whole structure of the heart were reduced by 52.5%, 65.5%, and 47%, respectively. The left anterior descending coronary artery, which was closely related to the target area, had a decrease of more than 20%. The mean values of V5, V10, V20, and Dmean of the affected lung were reduced by 21.6%, 24.8%, 25.0%, and 23.2%, respectively. The mean values of the doses of other endangered healthy organs, and the execution time of half-field segment arc plan were also better than the continuous arc plan. Conclusions:For breast cancer radiotherapy, the combination of half-field and VMAT can give full play to the advantages of half-field and VMAT, and significantly reduce the irradiated dose of the heart, affected lung, and healthy side of the breast.
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Objective:To evaluate the value and identify the prognosic factors of postoperative radiotherapy (PORT) in completely resected stage Ⅲ(pN 2) lung adenocarcinoma patients with epidermal growth factor receptor (EGFR) wild-type who received adjuvant chemotherapy. Methods:Clinical data of 172 patients with stage Ⅲ(pN 2) EGFR wild-type lung adenocarcinoma who underwent radical resection and adjuvant chemotherapy from 2009 to 2016 were retrospectively analyzed. All patients received platinum-based adjuvant chemotherapy combining two drugs for>4 cycles, and divided into the PORT group and the non-PORT group. The survival rate was calculated by Kaplan- Meier method and log-rank test, and multivariate prognostic analysis was performed by Cox’s regression model. Results:Among 172 patients, the median overall survival (OS), 3-year and 5-year OS rates were 40 months, 55.9% and 28.3%, respectively. The median disease-free survival (DFS), 3-year and 5-year DFS rates were 17 months, 24.5% and 13.0%, respectively. DFS was significantly improved in the PORT group (29 months vs. 13 months, P=0.001), whereas OS did not significantly differ between two groups (51 months vs. 38 months, P=0.151). In subgroup analysis, DFS of patients with multistation N 2 or the number of N 2 metastases of≥3 or skip N 2 in the PORT group was significantly longer ( P<0.05), whereas PORT exerted no significant effect on OS ( P>0.05). Conclusions:For patients with completely resected stage Ⅲ(N 2) EGFR wild-type lung adenocarcinoma receiving adjuvant chemotherapy, PORT might increase DFS and have a trend toward longer OS. However, these findings remain to be validated by large sample size investigations.
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Objective:To investigate whether radiotherapy should be delivered before the application of immune checkpoint inhibitor PD-1 in patients with advanced non-small cell lung cancer (NSCLC) and evaluate the effect of previous radiotherapy on the efficacy and pulmonary toxicity of PD-1 inhibitor.Methods:Clinical data of patients with stage Ⅳ NSCLC who received immunotherapy in Henan Cancer Hospital from March 2015 to September 2019 were retrospectively analyzed. The baseline data of patients, the status of radiotherapy and immunotherapy and the pulmonary toxicity were collected. According to whether radiotherapy was given before PD-1 inhibitor application, all patients were divided into the previous radiotherapy and non-radiotherapy groups. Survival analysis was performed by Kaplan- Meier method. Results:A total of 90 patients were enrolled including 39 cases in the previous radiotherapy group and 51 cases in the non-radiotherapy group. The median follow-up time was 22.9 months. The median progression-free survival (mPFS) in the previous radiotherapy group was 7.5 months (95% CI 5.4-9.5 months), significantly longer compared with 4.1 months (95% CI 3.1-5.1 months) in the non-radiotherapy group ( P=0.003). The median overall survival (mOS) significantly differed between two groups[15.2 months (95% CI 12.3-18.1 months) vs. 9.3 months (95% CI 6.1-12.5 months)]( P=0.040). The incidence of pulmonary toxicity showed no significant difference between two groups ( P=0.154). Conclusions:Patients with stage Ⅳ NSCLC patients in the previous radiotherapy group obtain significantly better mPFS and mOS and similar pulmonary toxicity compared with their counterparts in the non-radiotherapy group. Nevertheless, the findings remain to be validated by subsequent investigations with larger sample size.
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Objective:To evaluate the efficacy and safety of stereotactic ablative radiotherapy (SABR) in patients with pulmonary oligometastases.Methods:Clinical data of patients with pulmonary metastases treated with SABR from 2011 to 2018 were retrospectively analyzed. The local control rate (LCR) and overall survival (OS) were calculated by Kaplan- Meier method. log-rank test was used for univariate analysis and Cox’s regression model for multivariate analysis. Results:A total of 214 lung metastases were detected in 159 patients, and the median follow-up time was 43 months. The 1-, 3-and 5-year LCR were 90.1%, 73.9% and 65.8%, respectively. The 1-, 3-and 5-year OS were 73.8%, 43.6% and 11.9%, respectively. Univariate analysis showed that biological effective dose (BED)≥100 Gy was significantly correlated with LCR ( P=0.033). Cox’s multivariate analysis showed that BED and primary tumor source were the independent prognostic factors of LCR ( P=0.023, P=0.043). No>grade 3 adverse events were observed in all patients during treatment. Conclusions:SABR is a safe and effective treatment of lung oligometastases. SABR should be actively aD ministered for pulmonary oligometastases, especially for those with lesions from lung cancer and the radiation dose should be selected as BED ≥100 Gy.
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Objective:In this paper, based on the 4D dose distribution of the treatment plan, the effects of respiratory movement on the dose distribution of three-dimensional conformal radiation therapy (3DCRT) and sliding window intensity-modulated radiation therapy (SW-IMRT) techniques were analyzed, and the dose errors caused by respiratory movement based on the 4D dose distribution were evaluated.Methods:In this study, the dynamic thoracic phantom (CIRS-008A) was used to simulate the patient with a 3 cm spherical insert as the tumor. Four motion patterns were simulated with cos 4( x) and sin ( x) wave forms of 10 mm and 5 mm amplitudes. The 4DCT scans with the phantom were performed in different breathing modes, and the maximum intensity projection (MIP), average intensity projection (AIP) and 10 separate 4DCT phase images were transferred to the Eclipse treatment planning system. The targets were contoured on MIP, with corresponding 3DCRT and SW-IMRT plans designed and dose calculated on AIP. By copying the plan designed on the AIP to each phase image of the 4DCT set, the MATLAB software package was employed to register and superimpose all the phase-specific doses onto one of the reference phase to create a 4D-accumulated dose distribution. Both films (EBT2) and optically stimulated luminescence (OSLD) detectors were inserted in and around the target area of the phantom to measure the delivered doses. The calculated 4D-accumulated doses were compared to the measured doses and their differences were evaluated using Gamma analysis. Results:Under different respiration modes, the average Gamma index (3%/3 mm) passing rates between the 4D-accumulated doses and EBT2-measured doses for 3DCRT and SW-IMRT plans were (98.8±0.78)% and (96.4±1.89)%, respectively. The absolute measurements of OSLDs both inside and outside of the target area well matched the 4D-accumulated doses.Conclusions:4DCT can be effectively applied to evaluate the treatment plan dose distribution through 4D dose accumulation, which can potentially avoid cold spots and target under-coverage. Under different respiration modes, both 3DCRT and SW-IMRT plans provide dose measurements consistent with those predicted by the 4D-accumulated dose of treatment plan.
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Objective:To analyze the invasion characteristics and prognostic factors of patients with Masaoka-Koga stage Ⅲ thymoma.Methods:The tumor invasion characteristics of 179 patients who were diagnosed with Masaoka-Koga stage Ⅲ thymoma and treated in Affiliated Cancer Hospital of Zhengzhou University from January 2000 to June 2018 were analyzed retrospectively. According to the treatment methods, all patients were divided into the radical operation group ( n=94), palliative operation group ( n=39) and simple biopsy group ( n=46). The χ2 test was used to compare the classified variables, Kaplan- Meier method was utilized to calculate the cumulative survival rate, log-rank method was used for group comparison and univariate analysis, and Cox’s regression model was used for multivariate analysis. Results:Mediastinal pleural invasion (86.0%) was the most common site, followed by pericardium (50.8%), great vessel (40.8%) and lung (36.3%). The proportion of macrovascular invasion in the radical operation group was 14.9%, significantly lower than 79.5% and 60.9% in the palliative surgery group and biopsy group (both P<0.001). Multivariate analysis showed that the nature of operation ( P<0.001), age ( P=0.011), radiotherapy ( P=0.020) were the independent factors affecting overall survival (OS), while nature of operation ( P<0.001), age ( P=0.004), radiotherapy ( P=0.020), number of invasive organs ( P=0.023) and pathological type ( P=0.016) were the independent factors affecting progress-free survival (PFS). Conclusions:For patients with Masaoka-Koga stage Ⅲ thymoma, mediastinal pleura is the most common site of invasion, pericardium, lung and great vessels are also commonly invaded. The invasion of mediastinal pleura, pericardium and lung exerts slight effect on surgical resectability, whereas great vessel involvement can significantly affect surgical resectability. OS and PFS in patients undergoing radical resection are significantly better than those in patients treated with palliative resection and biopsy. Radical resection is the most important factor affecting prognosis.