Objective: To investigate the epidemiological characteristics of varicella outbreaks in primary and middle schools, and to establish a risk predictive model, so as to provide scientific guidance for the prevention of varicella outbreaks in schools. Methods: Based on a nested case-control study, primary and middle schools in 4 districts of Shanghai (Yangpu District and Jingan District) and Hangzhou (Xiaoshan District and Linping District) from January to December 2023 were selected to observe the status of varicella outbreaks. Associated factors of varicella outbreaks were investigated and used for establishing the predictive model, which was evaluated by the Hosmer-Lemeshow(H-L) goodness of fit test, receiver operating characteristic (ROC) curve, Calibration curve, decision curve analysis (DCA). Results: A total of 98 varicella outbreaks were included, with 195 schools without varicella outbreaks during the same period as controls. Eight factors, including the availability of warm water in restroom, availability of hand soap in restroom, average class size, duration of student attendance at school per day, presence of a fulltime school doctor, hesitancy of the school principal towards varicella vaccination, and rates of first and second doses of varicella vaccination, were identified as potential factors for school varicella outbreaks, with statistically significant differences (χ2/Z=10.01, 20.49, 17.43, 9.74, 32.17, 6.60, 2.20, 3.39, P<0.05). The 8 variables above were employed to construct a risk predictive model, and Hosmer-Lemeshow goodness of fit test yielded a χ2 value of 5.863 (P>0.05); the area under the ROC curve (AUC) was 0.846 (95%CI=0.799-0.893); Calibration curve analysis indicated good consistency between predicted and actual values of the model. DCA demonstrated favorable predictive performance of the model over a wide range. Conclusions The predictive model for school varicella outbreaks demonstrates satisfactory accuracy and efficacy. It suggested to make good use of this prediction model and take relevant measures to reduce the risk of varicella transmission in schools.

Patients with overlap syndrome(OS)of autoimmune liver disease may present with more than one biochemical,immunological,histological or cholangiography features of autoimmune liver disease(AILD)and often require a combination of immunosuppressants for treatment.Pulmonary cryptococcosis is a type of invasive pneumomycosis caused by Cryptococcus neoformans or Cryptococcus gattii and has a relatively high incidence rate in immunocompromised patients.This case report presents a patient with OS who was found to have pulmonary cryptococcosis during immunosuppressive therapy and developed abnormal liver function during antifungal treatment.Based on the liver function of the patient,the feasibility of adjusting antifungal agents was assessed,and active treatment strategies for novel cryptococcal infection were developed under the close monitoring of liver function,which helped to avoid the progression of infection.It is suggested that before the initiation of immunosuppressive therapy,systemic foci of infection should be comprehensively evaluated,and suspicious foci of infection should be monitored continuously.

L-asparaginase (L-ASN) is widely applied in the treatment of malignant tumor and low-acrylamide food production, however, the low expression level hampers its application. Heterologous expression is an effective strategy to increase the expression level of target enzymes, and Bacillus is generally used as the host for efficient production of enzymes. In this study, the expression level of L-asparaginase in Bacillus was enhanced through optimization of expression element and host. Firstly, five signal peptides (SP_SacC, SP_AmyL, SP_AprE, SP_YwbN and SP_WapA) were screened, among which SP_SacC showed the best performance, reaching an activity of 157.61 U/mL. Subsequently, four strong promoters (P43, P_ykzA-P43, P_Ubay and P_bacA) from Bacillus were screened, and tandem promoter P_ykzA-P43 showed the highest yield of L-asparaginase, which was 52.94% higher than that of control strain. Finally, three Bacillus expression hosts (B. licheniformis Δ0F3 and BL10, B. subtilis WB800) were investigated, and the maximum L-asparaginase activity, 438.3 U/mL, was reached by B. licheniformis BL10, which was an 81.83% increase compared with that of the control. This is also the highest level of L-asparaginase in shake flask reported to date. Taken together, this study constructed a B. licheniformis strain BL10/P_ykzA-P43-SP_SacC-ansZ capable of efficiently producing L-asparaginase, which laid the foundation for industrial production of L-asparaginase.
Bacillus licheniformis/metabolism* ; Asparaginase/genetics* ; Bacillus/genetics* ; Protein Sorting Signals ; Promoter Regions, Genetic/genetics* ; Bacillus subtilis/genetics* ; Bacterial Proteins

Objective:To compare the effect of O-arm assisted and free-hand pedicle screw placement in the treatment of AO type C thoracolumbar fracture.Methods:A retrospective cohort study was used to analyze the clinical data of 34 patients with type C thoracolumbar fracture admitted to Henan Provincial People′s Hospital from January 2018 to June 2021, including 23 males and 11 females; aged 42-63 years [(50.4±7.4)years]. The fracture was located at T 11 in 4 patients, T 12 in 10, L 1 in 12, L 2 in 6, T 11~12/L 1 in 1 and T 12/L 1 in 1. Posterior reduction and internal fixation was carried out for all patients, of whom 18 were treated with O-arm assisted pedicle screw placement (navigation group) and 16 with free-hand pedicle screw placement (free-hand group). The operation time, single screw placement time, intraoperative bleeding volume, operation mode and screw placement accuracy were compared between the two groups. The kyphotic Cobb angle, visual analogue score (VAS) and American Spinal Injury Association (ASIA) score were compared between the two groups before operation, at 1 week after operation, at 3 months after operation and at the last follow-up. Postoperative complications were observed. Results:All patients were followed up for 12-29 months [(16.8±6.1)months]. There was no significant difference between the two groups in the operation time, intraoperative bleeding volume and operation mode (all P>0.05). The single screw placement time was (9.4±1.6)minutes in navigation group, but was (10.8±1.5)minutes in free-hand group ( P<0.05). The screw placement accuracy was 97.4% in navigation group, but was 81.5% in free-hand group ( P<0.01). The kyphotic Cobb angle and VAS had no significant differences between the two groups before operation (all P>0.05). The kyphotic Cobb angle in navigation group and free-hand group was (4.3±1.1)° and (5.9±1.1)° at 1 week after operation, (4.4±1.2)° and (5.7±1.3)° at 3 months after operation, and (4.4±1.2)° and (6.8±0.9)° at the last follow-up, decreased significantly from that before operation [(21.8±3.1)°, (22.2±3.2)°] (all P<0.01). The kyphotic Cobb angle in navigation group was significantly lower than that in free-hand group at 1 week, 3 months after operation and at the last follow-up (all P<0.01). The VAS in navigation group and free-hand group was (3.2±0.7)points and (4.1±0.7)points at 1 week after operation, (2.4±0.6)points and (3.0±0.8)points at 3 months after operation, and (1.8±0.9)points and (2.6±0.7)points at the last follow-up, decreased significantly from that before operation [(8.4±0.8)points, (8.3±0.9)points] (all P<0.01). The VAS in navigation group was significantly lower than that in free-hand group at 1 week, 3 months after operation and at the last follow-up (all P<0.01). The ASIA score showed no significant difference within and between the two groups before operation, at 1 week, 3 months after operation and at the last follow-up (all P>0.05). Postoperative incision infection occurred in 1 patient in both groups ( P>0.05). Implant failure such as loosening or displacement was not observed in navigation group, and only occurred in 2 patients in free-hand group ( P>0.05). Conclusion:Compared with free-hand pedicle screw placement, O-arm assisted pedicle screw placement in the treatment of AO type C thoracolumbar fracture has advantages of rapid and accurate screw placement, good reduction and notable pain relief.

Objective:To evaluate the value of preoperative prediction of vessel invasion (VI) of locally advanced gastric cancer by machine learning model based on the venous phase enhanced CT radiomics features.Methods:A retrospective analysis of 296 patients with locally advanced gastric cancer confirmed by pathology in the First Affiliated Hospital of Zhengzhou University from July 2011 to December 2020 was performed. The patients were divided into VI positive group ( n=213) and VI negative group ( n=83) based on pathological results. The data were divided into training set ( n=207) and test set ( n=89) according to the ratio of 7∶3 with stratification sampling. The clinical characteristics of patients were recorded, and the independent risk factors of gastric cancer VI were screened by multivariate logistic regression. Pyradiomics software was used to extract radiomic features from the venous phase enhanced CT images, and the minimum absolute shrinkage and selection algorithm (LASSO) was used to screen the features, obtain the optimal feature subset, and establish the radiomics signature. Four machine learning algorithms, including extreme gradient boosting (XGBoost), logistic, naive Bayes (GNB), and support vector machine (SVM) models, were used to build prediction models for the radiomics signature and the screened clinical independent risk factors. The efficacy of the model in predicting gastric cancer VI was evaluated by the receiver operating characteristic curve. Results:The degree of differentiation (OR=13.651, 95%CI 7.265-25.650, P=0.003), Lauren′s classification (OR=1.349, 95%CI 1.011-1.799, P=0.042) and CA199 (OR=1.796, 95%CI 1.406-2.186, P=0.044) were independent risk factors for predicting the VI of locally advanced gastric cancer. Based on the venous phase enhanced CT images, 864 quantitative features were extracted, and 18 best constructed radiomics signature were selected by LASSO. In the training set, the area under the curve (AUC) of XGBoost, logistic, GNB and SVM models for predicting gastric cancer VI were 0.914 (95%CI 0.875-0.953), 0.897 (95%CI 0.853-0.940), 0.880 (95%CI 0.832-0.928) and 0.814 (95%CI 0.755-0.873), respectively, and in the test set were 0.870 (95%CI 0.769-0.971), 0.877 (95%CI 0.788-0.964), 0.859 (95%CI 0.755-0.961) and 0.773 (95%CI 0.647-0.898). The logistic model had the largest AUC in the test set. Conclusions:The machine learning model based on the venous phase enhanced CT radiomics features has high efficacy in predicting the VI of locally advanced gastric cancer before the operation, and the logistic model demonstrates the best diagnostic efficacy.

OBJECTIVE: To assess the practical and health economical values of non-invasive prenatal test (NIPT) in Changsha Municipal Public Welfare Program. METHODS: A retrospective analysis was carried out on 149 165 women undergoing NIPT test from April 9, 2018 to December 31, 2019. For pregnant women with high risks, invasive prenatal diagnosis and follow-up of pregnancy outcome were conducted. The cost-benefit of NIPT for Down syndrome was analyzed. RESULTS: NIPT was carried out for 149 165 pregnant women and succeeded in 148 749 cases (99.72%), for which outcome were available in 148 538 (99.86%). 90% of pregnant women from the region accepted the screening with NIPT. 415 (0.27%) were diagnosed as high risk. Among these, 381 (91.81%) accepted amniocentesis, which led to the diagnosis of 212 cases of trisomy 21 (PPV=85.14%), 41 cases with trisomy 18 (PPV=48.81%) and 10 cases with trisomy 13 (PPV=20.83%). The sensitivity and specificity of NIPT for trisomy 21, trisomy 18 and trisomy 13 were (97.70%, 99.98%), (97.62%, 9.97%) and (100%, 99.97%), respectively. In addition, 213 and 30 cases were diagnosed with sex chromosomal aneuploidies (PPV=46.2%) and other autosomal anomalies (PPV=16.57%), respectively. For Down syndrome screening, the cost and benefit of the project was 120.79 million yuan and 1,056.95 million yuan, respectively. The cost-benefit ratio was 1: 8.75, and safety index was 0.0035. CONCLUSION NIPT is a highly accurate screening test for trisomy 21, which was followed by trisomy 18 and sex chromosomal aneuploidies, while it was less accurate for other autosomal aneuploidies. The application of NIPT screening has a high health economical value.
Aneuploidy ; Cost-Benefit Analysis ; Female ; Humans ; Noninvasive Prenatal Testing ; Pregnancy ; Retrospective Studies ; Trisomy 18 Syndrome/genetics*

Objective:To construct a model of early neurological deterioration (END) in acute ischemic stroke (AIS), and to evaluate the predictive value of this model.Methods:From February 2018 to December 2020, 263 cases of AIS patients admitted to Response General Hospital were selected as research objects. According to whether END occurs, they were divided into END group (80 cases) and non-END group (183 cases). Logistic regression was used to analyze the independent risk factors of AIS concurrent END, and the predictive model of the above factors was constructed. The value of the model was evaluated by receiver operating characteristic (ROC) curve, correction curve and decision curve analysis (DCA).Results:Systolic blood pressure, diastolic blood pressure, fasting plasma glucose, total cholesterol, National Institutes of Health Stroke Scale (NIHSS) and door to needle time (DNT) in the END group were (144.66 ± 18.08) mmHg(1 mmHg=0.133 kPa), (84.04 ± 8.47) mmHg, (6.15 ± 1.00) mmol/L, (4.82 ± 1.08) mmol/L, (14.90 ± 4.95) points, (4.58 ± 1.02) h, all higher than those in the non-END group (132.32 ± 15.53) mmHg, (81.19 ± 11.00) mmHg, (5.53 ± 0.98) mmol/L, (4.51 ± 1.15) mmol/L, (11.37 ± 3.32) points, (3.22 ± 1.08) h, and the level of high density lipoprotein cholesterol was (1.09 ± 0.07) mmol/L in the END group,lower than that in the non-END group (1.15 ± 0.08) mmol/L, the differences were statistically significant ( t values were 2.07-9.53, all P<0.05). Logistic regression analysis showed that fasting plasma glucose ( OR=2.25, 95% CI 1.50-3.40, P<0.05), systolic blood pressure ( OR=1.04, 95% CI 1.02-1.07, P<0.05), NIHSS score ( OR=1.26, 95% CI 1.14-1.39, P<0.05) and DNT ( OR=3.44, 95% CI 2.30-5.14, P<0.05) were independent risk factors for AIS concurrent END. The area under ROC curve, sensitivity and specificity of the model X composed of fasting plasma glucose, systolic blood pressure, NIHSS scores and DNT for diagnosing AIS concurrent END were 0.90 (95% CI 0.87-0.94), 90.00% and 77.60% respectively. The calibration curve of model X had a high coincidence with the ideal curve. Conclusions:The model X composed of fasting plasma glucose, systolic blood pressure, NIHSS score and DNT has high application value for the prediction of END, which can assist the clinic to make better decision.

Objective:To investigate the influences of age-adjusted Charlson comorbidity index (ACCI) on prognosis of patients undergoing laparoscopic radical gastrectomy.Methods:The retrospective cohort study was conducted. The clinicopathological data of 242 gastric cancer patients who underwent laparoscopic radical gastrectomy in 19 hospitals of the Chinese Laparoscopic Gastrointestinal Surgery Study Group-04 study, including 54 patients in Fujian Medical University Union Hospital, 32 patients in the First Hospital of Putian City, 32 patients in Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 31 patients in Zhangzhou Affiliated Hospital of Fujian Medical University, 17 patients in Nanfang Hospital of Southern Medical University, 11 patients in the First Affiliated Hospital with Nanjing Medical University, 8 patients in Qinghai University Affiliated Hospital, 8 patients in Meizhou People′s Hospital, 7 patients in Fujian Provincial Hospital, 6 patients in Zhongshan Hospital of Fudan University, 6 patients in Longyan First Hospital, 5 patients in the First Affiliated Hospital of Xinjiang Medical University, 5 patients in the First Hospital Affiliated to Army Medical University, 4 patients in the Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, 4 patients in West China Hospital of Sichuan University, 4 patients in Beijing University Cancer Hospital, 3 patients in the First Affiliated Hospital of Xiamen University, 3 patients in Guangdong Provincial People′s Hospital, 2 patients in the First Affiliated Hospital of Xi′an Jiaotong University, from September 2016 to October 2017 were collected. There were 193 males and 49 females, aged 62(range, 23?74)years. Observation indicators: (1) age distribution, comorbidities and ACCI status of patients; (2) the grouping of ACCI and comparison of clinicopathological characteristics of patients in each group; (3) incidence of postoperative early complications and analysis of factors affecting postoperative early complications; (4) follow-up; (5) analysis of factors affecting the 3-year recurrence-free survival rate of patients. Follow-up was conducted using outpatient examination or telephone interview to detect postoperative survival of patients up to December 2020. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M( Q1, Q3) or M(range), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was conducted using the nonparametric rank sum test. The X-Tile software (version 3.6.1) was used to analyze the best ACCI grouping threshold. The Kaplan-Meier method was used to calculate survival rates and draw survival curves. The Log-Rank test was used for survival analysis. The Logistic regression model was used to analyze the factors affecting postoperative early complications. The COX proportional hazard model was used for univariate and multivariate analyses of factors affecting the 3-year recurrence-free survival rate of patients. Multivariate analysis used stepwise regression to include variables with P<0.05 in univariate analysis and variables clinically closely related to prognosis. Results:(1) Age distribution, comor-bidities and ACCI status of patients. Of the 242 patients, there were 28 cases with age <50 years, 68 cases with age of 50 to 59 years, 113 cases with age of 60 to 69 years, 33 cases with age of 70 to 79 years. There was 1 patient combined with mild liver disease, 1 patient combined with diabetes of end-organ damage, 2 patients combined with peripheral vascular diseases, 2 patients combined with peptic ulcer, 6 patients combined with congestive heart failure, 8 patients combined with chronic pulmonary diseases, 9 patients with diabetes without end-organ damage. The ACCI of 242 patients was 2 (range, 0-4). (2) The grouping of ACCI and comparison of clinicopathological characteristics of patients in each group. Results of X-Tile software analysis showed that ACCI=3 was the best grouping threshold. Of the 242 patients, 194 cases with ACCI <3 were set as the low ACCI group and 48 cases with ACCI ≥3 were set as the high ACCI group, respectively. Age, body mass index, cases with preoperative comorbidities, cases of American Society of Anesthesiologists classification as stage Ⅰ, stage Ⅱ, stage Ⅲ, tumor diameter, cases with tumor histological type as signet ring cell or poorly differentiated adenocarcinoma and cases with tumor type as moderately or well differentiated adenocarcinoma, cases with tumor pathological T staging as stage T1, stage T2, stage T3, stage T4, chemotherapy cycles were (58±9)years, (22.6±2.9)kg/m 2, 31, 106, 85, 3, (4.0±1.9)cm, 104, 90, 16, 29, 72, 77, 6(4,6) in the low ACCI group, versus (70±4) years, (21.7±2.7)kg/m 2, 23, 14, 33, 1, (5.4±3.1)cm, 36, 12, 3, 4, 13, 28, 4(2,5) in the high ACCI group, showing significant differences in the above indicators between the two groups ( t=-14.37, 1.98, χ2=22.64, Z=-3.11, t=-2.91, χ2=7.22, Z=-2.21, -3.61, P<0.05). (3) Incidence of postoperative early complications and analysis of factors affecting postoperative early complications. Of the 242 patients, 33 cases had postoperative early complications, including 20 cases with local complications and 16 cases with systemic complica-tions. Some patients had multiple complications at the same time. Of the 20 patients with local complications, 12 cases had abdominal infection, 7 cases had anastomotic leakage, 2 cases had incision infection, 2 cases had abdominal hemorrhage, 2 cases had anastomotic hemorrhage and 1 case had lymphatic leakage. Of the 16 patients with systemic complications, 11 cases had pulmonary infection, 2 cases had arrhythmias, 2 cases had sepsis, 1 case had liver failure, 1 case had renal failure, 1 case had pulmonary embolism, 1 case had deep vein thrombosis, 1 case had urinary infection and 1 case had urine retention. Of the 33 cases with postoperative early complications, there were 3 cases with grade Ⅰ complications, 22 cases with grade Ⅱ complications, 5 cases with grade Ⅲa complications, 2 cases with grade Ⅲb complications and 1 case with grade Ⅳ complica-tions of Clavien-Dindo classification. Cases with postoperative early complications, cases with local complications, cases with systemic complications were 22, 13, 9 in the low ACCI group, versus 11, 7, 7 in the high ACCI group, respectively. There were significant differences in cases with postoperative early complications and cases with systemic complications between the two groups ( χ2=4.38, 4.66, P<0.05), and there was no significant difference in cases with local complications between the two groups ( χ2=2.20, P>0.05). Results of Logistic regression analysis showed that ACCI was a related factor for postoperative early complications of gastric cancer patients undergoing laparoscopic radical gastrectomy [ odds ratio=2.32, 95% confidence interval ( CI) as 1.04-5.21, P<0.05]. (4) Follow-up. All the 242 patients were followed up for 36(range,1?46)months. During the follow-up, 53 patients died and 13 patients survived with tumor. The 3-year recurrence-free survival rate of the 242 patients was 73.5%. The follow-up time, cases died and cases survived with tumor during follow-up, the 3-year recurrence-free survival rate were 36(range, 2-46)months, 29, 10, 80.0% for the low ACCI group, versus 35(range, 1-42)months, 24, 3, 47.4% for the high ACCI group. There was a significant difference in the 3-year recurrence-free survival rate between the two groups ( χ2=30.49, P<0.05). (5) Analysis of factors affecting the 3-year recurrence-free survival rate of patients. Results of univariate analysis showed that preoperative comorbidities, ACCI, tumor diameter, histological type, vascular invasion, lymphatic invasion, neural invasion, tumor pathological TNM staging, postoperative early complications were related factors for postoperative 3-year recurrence-free survival rate of gastric cancer patients undergoing laparoscopic radical gastrectomy [ hazard ratio ( HR)=2.52, 3.64, 2.62, 0.47, 2.87, 1.90, 1.86, 21.77, 1.97, 95% CI as 1.52-4.17, 2.22-5.95, 1.54-4.46, 0.27-0.80, 1.76-4.70, 1.15-3.12, 1.10-3.14, 3.01-157.52, 1.11-3.50, P<0.05]. Results of multivariate analysis showed that ACCI, tumor pathological TNM staging, adjuvant chemotherapy were indepen-dent influencing factors for postoperative 3-year recurrence-free survival rate of gastric cancer patients undergoing laparoscopic radical gastrectomy ( HR=3.65, 11.00, 40.66, 0.39, 95% CI as 2.21-6.02, 1.40-86.73, 5.41-305.69, 0.22-0.68, P<0.05). Conclusions:ACCI is a related factor for post-operative early complications of gastric cancer patients undergoing laparos-copic radical gastrectomy. ACCI, tumor pathological TNM staging, adjuvant chemotherapy are indepen-dent influencing factors for postoperative 3-year recurrence-free survival rate of gastric cancer patients undergoing laparoscopic radical gastrectomy.

Objective:To investigate anticoagulant effects of mechanical methods in obese patients undergoing laparoscopic sleeve gastrectomy (LSG).Methods:In this prospective study, 54 obese patients receiving LSG were enrolled . All patients were given post-op mechanical methods for thrombogenic interventions. BMI and the operation-related factors were recorded. Venous blood specimens were taken from each patient before surgery, at the end of pneumoperitoneum (i.e., 0 h after surgery), at 24 hours after surgery for prothrombin time (PT) and activated partial thromboplastin time (APTT), fibrinogen (FIB) and D-dimer (D-D).Results:All 54 obese patients successfully underwent LSG. No severe complications were observed. Before operation, the mean BMI was (43.49±8.29) kg/m 2. DVT-2600 device was applied in all patients for 3 consecutive days after surgery. The PT values increased at 0 h, 24 h after surgery [(12.4±1.2) s, (12.4±0.8) s vs. (11.2±0.8) s, P=0, 0]. The APTT values at 0 h, 24 h after surgery decreased [(29.7±3.6) s, (29.0±3.1) s vs.(31.2±3.3) s, P=0.020, 0.001]. However, the D-D values increased at 0 h,24 h after operation [(213±143) ng/ml ,(445±237) ng/ml vs. (85±108) ng/ml, P=0, 0]. All patients were followed up for 1 month, and no thrombosis -related complications were observed. Conclusion:Mechanical methods for obese patients after LSG can help decrease the risk of deep venous thrombosis.

Objective:To investigate the effectiveness of postoperative radiotherapy using shrinking field for patients with extremity soft tissue sarcoma (STS), mainly focusing on the local control rate and adverse events.Methods:Clinical data of 49 extremity STS patients who received postoperative intensity-modulated radiotherapy in the First Hospital of Tsinghua University from October 2017 to March 2021 were retrospectively analyzed. Target volumes were contoured on CT and MRI fusion images. The tumor bed was defined as GTV tb, with 3 cm expansion in the longitudinal direction and 1.5 cm expansion in the radial direction to construct CTV (the target volume should be properly repaired according to the anatomical barrier, and the edema area around the tumor should be included). GTV tb and CTV were expanded in all directions by 0.5 cm to construct PTV1 and PTV2 respectively, at a dose of 95%PTV1 63-66 Gy, 95%PTV2 50-56 Gy,1.8-2.0 Gy/f. The dose of surgical volume should be given at 70 Gy for patients who had a microscopic positive margin. Results:The median follow-up time was 32.1 months (7.9-45.6 months). The 3-year local failure-free survival (LFFS), overall survival (OS)and distant metastasis-free survival (DMFS) were 91.7%,77.6% and 71.5%, respectively. Univariate analysis showed that patients with a microscopic positive margin were more likely to develop local recurrence ( P<0.05). The incidence of grade 2 or above wound complications, joint stiffness, fracture, edema and skin fibrosis were 2%, 4.1%, 2%, 8.2% and 26.5%, respectively. Conclusion:Postoperative radiotherapy with shrinking field provides excellent local control rate and low incidence of late adverse events in patients with extremity STS.