Objective　To investigate the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) deficiency in the pathogenesis of Exophiala oligosperma (E. oligosperma) infection, a dematiaceous fungus, aiming to provide new insights and evidence for the treatment of dematiaceous fungal infections. Methods　C57BL/6 wild-type (WT) mice and Csf2 gene knockout (KO) mice (C57BL/6 background) were selected. Using E. oligosperma isolated from patients with caspase recruitment domain-containing protein 9 (CARD9) gene deficiency, a murine subcutaneous infection model was established to simulate the human infection route. The natural progression of infection in the mice was observed for six weeks, with skin lesion tissues collected at appropriate time points for pathological analysis and monitoring immune responses. Results　Both WT and Csf2 KO mice exhibited spontaneous pathogen clearance and gradual recovery of foot tissue appearance during the progression of infection, with a 100% survival rate at the end of observation. Compared to WT mice, Csf2 KO mice showed reduced footpad swelling at 1 and 2 weeks post-infection (t=4.674, t=5.961, P<0.01). Fungal clearance in Csf2 KO mice was delayed, with fungal colonies still detectable in lesion tissues at week 4, and Periodic Acid-Schiff (PAS)-positive fungal spores observed in histopathological sections. There was no significant difference found in macrophage infiltration between WT and Csf2 KO mice during the early stages of infection (1-2 weeks) (P>0.05), while neutrophil infiltration was significantly reduced in Csf2 KO mice at week 2 (t=3.287, P<0.01). In addition, Csf2 KO mice exhibited lower levels of IL-6 and IL-1β in foot lesion homogenates at week 1 (t=4.686, t=4.102, P<0.05). Conclusions　This study demonstrated that GM-CSF deficiency delays pathogenic fungi clearance, prolongs the disease course and affects early inflammatory cytokine production as well as neutrophil infiltration during the early stages of fungal infections.

[Objective] To explore the influencing factors of quality monitoring index on the nucleic acid pooling detection mode and continuously improve the detection quality of nucleic acid laboratory. [Methods] The quality monitoring indicators (NAT reactive rate, NAT resolution reactive rate, NAT invalid batch rate, NAT invalid result rate, equipment failure rate) and causes of invalidity in our laboratory from January 1, 2020 to December 31, 2022 were retrospectively analyzed. The quality monitoring indicators of the laboratory during 2020 to 2022 were compared longitudinally. The quality monitoring indicators of the laboratory in 2022 were compared horizontally with the overall level in Shandong for the same period to find the differences. [Results] From 2020 to 2022, a total of 218 686 samples were detected, the NAT reactive rate was 0.15‰ (32 samples in total), the resolution reactive rate was 39.02%, the invalid batch rate was 1.06%, the invalid result rate was 1.18%, and the equipment failure rate was 3.58%. There were no differences in the NAT reactive rate, NAT resolution reactive rate and NAT invalid batch rate among different years (P>0.05), but there were differences in the invalid result rate (P<0.05). Equipment failure was the main cause of invalid results (56.53%). Compared with other laboratories in Shandong, there were differences in the NAT reactive rate and invalid result rate (P<0.05). There were differences in the reaction rate, resolution rate and invalid result rate among different reagents (P<0.05). Compared with other two laboratories using the same manufacturer's reagent, there were differences in the reactive rate and invalid result rate (P<0.05), but no difference in the resolution rate and invalid batch rate (P>0.05). [Conclusion] Establishing quality indexes for process control and regular analysis can timely detect potential risks in laboratory operation. The use of quality indicators to implement self-comparison and inter-laboratory comparison can help the laboratory systematically and scientifically evaluate its own operating status and formulate corresponding quality management strategies, thereby improving the laboratory's testing capacity and ensure the safety of blood use.

Objective:To investigate the effects of preoperative enteral nutrition on nutrition-related complications and gastrointestinal function in esophageal cancer patients by administering EN before surgery.Methods:A total of 215 patients who underwent thoracoscopic esophagectomy at Nanjing Hospital of Traditional Chinese Medicine between January 2018 and December 2020 were retrospectively analyzed in this study. Among them, 145 patients received enteral nutrition preconditioning, while 70 patients received traditional nutritional support. The nutritional risk was assessed according to the Nutritional Risk Screening 2002 (NRS2002), and the patients were categorized into non-nutritional risk group (NRS2002<3) and nutritional risk group (NRS2002≥3). Patients in the traditional nutritional support group with NRS2002<3 were provided with a regular diet three days prior to surgery, whereas those with NRS2002≥3 received intravenous fat emulsion amino acid glucose for nutritional support. In the enteral nutrition preconditioning group, patients with NRS2002<3 received 500 mL/d of enteral nutrition suspension orally in addition to their regular diet for 3 days preoperatively; those with NRS2002≥3 received received 1000 mL/d of enteral nutrition suspension orally or via gastric tube. Postoperative hospital stay, time to gas passage and defecation, hospital expenses, gastrointestinal dysfunction incidence including diarrhea, abdominal distension and constipation, postoperative routine blood indicators, anastomotic fistula occurrence as well as infectious complications such as pneumonia and wound infection were compared between groups. Measurement data with normal distribution was expressed as Mean±SD, independent sample t-test was used on comparison between groups. Counting data was expressed as case(%), χ2 test was used on comparison between groups, P<0.05 was considered as statistically significant. Results:The incidence of anastomotic leakage and infectious complications in the enteral nutrition pre-adaptation group was 4.83% (7/145) and 4.83% (7/145), respectively, showing no statistically significant differences compared to the traditional nutrition support group [2.86% (2/70) and 8.57% (6/70)] ( χ2=0.46 and 1.16, P=0.499 and 0.280, respectively). The incidences of gastrointestinal dysfunction and overall complications in the enteral nutrition pre-adaptation group were 5.52% (8/145) and 13.10% (19/145), respectively, which were significantly lower than those in the traditional nutrition support group [37.14% (26/70) and 45.71% (32/70)] ( χ2=35.47 and 27.75, both P<0.001). Postoperative outcomes in the enteral nutrition pre-adaptation group, including hospital stay (14.05±3.75 days), time to first flatus (25.75±5.03 hours), time to first defecation (49.25±5.98 hours), and hospitalization costs (85,200±13,500 CNY), were significantly better than those in the traditional nutrition support group [(16.46±4.79 days, 31.53±6.55 hours, 63.45±11.43 hours, and 93,500±20,100 CNY)] ( t=3.70, 6.52, 9.77, and 3.17, all P<0.001). No significant differences were observed in routine postoperative blood tests between the two groups (all P>0.05). Stratified analysis revealed that among patients with preoperative nutritional risk, the enteral nutrition pre-adaptation group demonstrated superior outcomes in hospitalization costs (82,300±11,000 CNY), time to first flatus (26.17±5.69 hours), time to first defecation (50.31±5.59 hours), overall complication rate (15.79%), and gastrointestinal dysfunction rate (7.89%) compared to the traditional nutrition support group [100,800±28,800 CNY, 31.42±6.29 hours, 60.80±9.89 hours, 54.55%, and 40.91%] ( t=2.89, P=0.008; t=3.32, P=0.002; t=4.57, P<0.001; χ2=9.97, P=0.002; χ2=9.49, P=0.002). Similarly, among patients without preoperative nutritional risk, the enteral nutrition pre-adaptation group showed better results in hospital stay (13.69±3.83 days), time to first flatus (25.60±4.80 hours), time to first defecation (48.87±6.10 hours), overall complication rate (12.15%), and gastrointestinal dysfunction rate (4.67%) compared to the traditional nutrition support group [16.60±4.36 days, 31.58±6.73 hours, 64.67±11.98 hours, 41.67%, and 35.42%] ( t=4.19, t=5.56, t=8.65, χ2=17.23, χ2=25.72, all P<0.001). Conclusion:Enteral nutrition pre-adaptation positively impacts post-esophagectomy nutrition-related complications and gastrointestinal dysfunction.nutrtional support before surgery can't be neglected.

Objective:To explore the diagnostic value of transcranial magnetic stimulation (TMS), transsacral magnetic root stimulation combined with sacral reflexes, external anal sphincter electromyography and pudendal nerve somatosensory evoked potentials in the assessment of neurogenic lower urinary tract dysfunction (NLUTD).Methods:Twenty-one NLUTD patients (1 with a supra-pontine lesion, 5 with a spinal cord injury, 5 with a cauda equina injury, and 10 with pelvic floor disorders) were enrolled. Needle electromyography (EMG) was used to record TMS-induced and transsacral magnetic stimulation-induced motor evoked potentials (tc-MEPs and ts-MEPs, respectively) related to the external anal sphincter (EAS). The dorsal nerve of the penis or clitoris was stimulated electrically to record the latency of the sacral reflex related to the EAS. Central motor conduction time (CMCT) and the tc/ts-MEP latency ratio were calculated to distinguish central from peripheral lesions.Results:In the one patient with a supra-pontine lesion, although the tc-MEP and ts-MEP latencies were within normal limits, the CMCT was prolonged (28.2ms) and the tc/ts-MEP ratio was large (7.4). Among the five patients with a spinal cord injury, one exhibited prolonged tc-MEP latency (50.6ms) and CMCT (47.8ms), along with a large tc/ts-MEP ratio (18.1). In the five patients with cauda equina injury and the ten with NLUTD secondary to pelvic floor disorders, CMCT was within the normal range [averaging (22.9±4.9ms) and (24.2±3.5ms), respectively], but the ts-MEP latency was prolonged [(7.1±2.1ms) and (8.6±3.7ms), respectively], and the tc/ts-MEP ratio was small [(4.4±0.9) and (4.3±1.5), respectively]. The tc/ts-MEP ratio demonstrated the best rate of abnormality detection (93.8%), with an area under the curve of 0.99, indicating good sensitivity.Conclusions:The tc/ts-MEP ratio can be useful for distinguishing central and peripheral lesions. A markedly increased tc/ts-MEP ratio may suggest central nervous system injury, whereas a decreased ratio may indicate peripheral nervous system injury.

AIM:This study aims to investigate the mechanism by which LINC00973 regulates multidrug re-sistance of non-small-cell lung cancer(NSCLC).METHODS:The GEPIA database was employed to analyze the expres-sion levels of LINC00973 in NSCLC and its correlation with patient prognosis in clinical settings.RT-qPCR was utilized to assess LINC00973 expression in various NSCLC cell lines and chemoresistant cells.The migration,invasion,stemness ca-pacity,and drug sensitivity of NSCLC cells with either overexpression or knockdown of LINC00973 were evaluated using wound healing assay,Transwell assay,sphere formation assay,and CCK-8 assay.RNA sequencing was conducted on LINC00973-overexpressing and parental NSCLC cells to identify dysregulated pathways and targets.The LncBase Pre-dicted v.2 and TargetScan databases were used to predict the microRNAs(miRNAs)co-bound by LINC00973 and their target genes.Mimics and inhibitors of candidate miRNAs were synthesized and transfected into NSCLC cells subjected to LINC00973 overexpression or knockdown.Changes in the expression level of LINC00973,and the mRNA and protein ex-pression levels of its target genes were assessed using RT-qPCR and Western blot.RESULTS:Analysis of the GEPIA da-tabase revealed that LINC00973 was significantly up-regulated in lung adenocarcinoma and lung squamous cell carcino-ma,correlating with poor prognosis of NSCLC patients.The LINC00973 expression was elevated in various NSCLC and chemoresistant cell lines(A549/DDP and A549/5-FU).Overexpression of LINC00973 in A549 and H520 cells markedly enhanced their migration,invasion,and stemness capabilities,while concurrently reducing sensitivity to chemotherapy and targeted therapies.RNA sequencing,along with RT-qPCR results,indicated that ATP-binding cassette transporter G5(ABCG5)was activated in LINC00973-overexpressing A549 and H520 cells.Further database analyses and dual trans-fection experiments confirmed that LINC00973 regulated ABCG5 expression through competitive binding with hsa-miR-150-5p.CONCLUSION:LINC00973,which is aberrantly up-regulated in NSCLC specimens and associated with poor clinical prognosis,promotes the expression of ABCG5 through competitive binding with hsa-miR-150-5p.This interaction leads to en-hanced invasion,stemness,and multidrug resistance in NSCLC cells.

Objective To provide relevant suggestions for ethical considerations in clinical research by searching literature related to ethics in clinical research using the visualization analysis software CiteSpace,and to analyze and compare the current research status of clinical research ethics at home and abroad.Methods The papers on the application of medical ethics in clinical trials from the core collection of CNKI and Web of Science databases were collected and the bibliometric software CiteSpace was used to draw a knowledge map of domestic and foreign literature.The research hotspots and development trends of medical ethics in clinical trials were analyzed.Results In terms of the process of informed consent,risk minimization,fair selection,and protection on the rights and interests of vulnerable groups,the focus of medical ethics research in China were basically consistent with foreign literature.The difference was that foreign research focused more on ethical education,the quality of life of research participants,and ethical counseling.Otherwise,domestic research focused more on the quality management of clinical trials and the specificity of traditional Chinese medicine research,with research on vulnerable groups mostly focused on children.Conclusion Chinese researchers should strengthen multi-dimensional research on medical ethics in China,and gradually expand their view from ethical review points and management research to applied research solved clinical problems and the specificity of research participants,and increasing the number and dimensions of research.

Objective To find out whether photobiomodulation(PBM)can mitigate cognitive dysfunction caused by chronic stress by affecting levels of adenosine triphosphate(ATP)and adenosine receptors.Methods Twenty-four C57BL/6J mice were randomly divided into a control group,a stress group,and a treatment group.Chronic unpredictable mild stress was used to establish a mouse model of stress.Six weeks into modeling,the treatment group was subjected to one week of PBM interventions.Behavioral tests were conducted to observe behavioral changes in the mice.Western blotting(WB)was used to detect the expressions of A1,A2B,and A3 adenosine receptors in the hippocampus and prefrontal cortex of mice in the three groups.Twelve C57BL/6J mice were randomly divided into a control group and an intervention group.The intervention group received a week of PBM interventions and underwent behavioral testing.WB was used to detect the expression changes of A1,A2B,and A3 adenosine receptors in the hippocampus and prefrontal cortex in both groups.Immunofluorescence assay was adopted to detect the expression of c-Fos in the hippocampus of mice in the two groups.The ATP assay kit made by Beyotime Biotechnology Co.,Ltd.was used to measure changes in ATP contents in the hippocampus and prefrontal cortex tissues of mice.Cell experiments were conducted to verify the effect of PBM on intracellular ATP contents.Results Mice in the stress group covered a similar distance to the control group,but finished far fewer platform crossings.There was no significant difference between the treatment group and the control group in the number of times of platform crossings,but compared favorably with the stress group where the levels of adenosine receptors in the hippocampus and prefrontal cortex were lower,but were increased by PBM.After PBM interventions in normal mice,platform crossings were increased significantly compared to the control group.PBM also raised adenosine receptor levels and ATP contents in the hippocampus and prefrontal cortex,and increased hippocampal c-Fos expressions.In vitro,PBM elevated intracellular ATP levels.Conclusion PBM may improve chronic stress-induced cognitive dysfunction by regulating ATP levels and adenosine receptor expressions,thereby modulating neuronal responsiveness in the hippocampus.

Objective:To investigate the effect of nuclear receptor subfamily 2 group F member 2(NR2F2)on the biological behaviors of human ovarian cancer SKOV3 cells,and to clarify its molecular mechauism and provide the new idea for treatment of ovarian cancer.Methods:Gene Expression Profiling Interactive Analysis(GEPIA)Database analyse the expression level of NR2F2 gene in ovarian tissue,and analyse its correlation with clinical prognosis of ovarian cancer patients.The human ovarian cancer SKOV3 cells were divided into control group and NR2F2 over-expression(NR2F2 OE)group,which were transfected with mCherry control virus and NR2F2 OE over-expression virus,respectively,when the cell deusity reached 70％,and the stable transfection SKOV3 cell lines were screened with puromycin(puro)48h lafter.Real-time fluorescence quantitative PCR(RT-qPCR)and Western blotting methods were used to detect the transfection efficiencies of the cells;RT-qPCR method was used to detect the expression levels of NR2F2 and sex-determining region Y-box 2(SOX2)mRNA in the cells in two groups;Western blotting method was used to detect the expression levels of NR2F2,ATP-binding cassette superfamily G member 2(ABCG2),and programmed cell death 1-ligand 1(PD-L1)protcins in the cells in two groups.CCK-8 assay was used to detect the proliferation activities of the cells in two groups;Wound assay was used to detect the migration rates of the cells in two groups;Transwell chamber assay was used to detect the number of transmembrane cells;Spheroidization assay was used to detect the numbers of spheroids in the cells;peripheral blood mononuclear cells(PBMCs)-mediated tumor cell killing assay was used to detect the relative densities of surviving tumor cells;CCK-8 assay was used to detect the half maximal inhibitory concentration(IC50)of paclitaxel(PTX)and carboplatin(CBP).Results:Compared with normal ovarian tissue,the expression level of NR2F2 gene in ovarian tumor tissue was decreased(P＜0.05),and decreased with the improvement of clinical pathological grading of ovarian tumor.The patients with higher expression level of NR2F2 gene had better clincal prognosis.The SKOV3 cells with NR2F2 over-expresson were successfully constructed,and the expression levels of NR2F2 mRNA and protein in the cells in NR2F2 OE group were increased compared with control group(P＜0.001).The CCK-8 assay results showed that compared with control group,the proliferation activities of the cells in NR2F2 OE group were decreased at different time points(1,2,3,and 4 d)(P＜0.05 or P＜0.01).The cell wound assay results showed that compared with control group,the migration rate of the cells in NR2F2 OE group was decreased(P＜0.001).The Transwell assay results showed that compared with control group,the number of transmembrane cells in NR2F2 OE group was decreased(P＜0.01).Compared with control group,the number of the spheroids in NR2F2 OE group was decreased(P＜0.05),and the expression levels of SOX2 mRNA(P＜0.01)and protein(P＜0.001)were increased.Compared with control group,the relative density of surviving tumor cells in NR2F2 OE group was decreased,but the difference was not significant(P＜0.05),and the expression level of PD-L1 protein was decreased(P＜0.05).Compared with control group,the proliferation activities of cells in NR2F2 OE group were decreased(P＜0.05),and the drug sensitivities of the cells to PTX and CBP were enhanced(P＜0.05);the IC50 of PTX was significantly reduced,while the IC50of CBP could not be calculated due to excessively high drug concentration;the expression level of ABCG2 protein was decreased(P＜0.05).Conclusion:The over-expression of NR2F2 may inhibit the proliferation,migration,and invasion of the human ovarian cancer SKOV3 cells,decrease the expression levels of SOX2,PD-L1 and ABCG2 proteins,suppress the stemness and immune evasion ability of the SKOV3 cells,and enhance the sensitivities of the SKOV3 cells to PTX and CBP.

Cerebral blood flow directly affects the metabolism of substances and neural activity in the brain, and is closely associated with the occurrence and development of cerebral small vessel disease (CSVD). Multiple studies have revealed that various imaging biomarkers in patients with CSVD, such as lacunar infarction, enlarged perivascular spaces, cerebral microbleeds, cerebral atrophy, and white matter hyperintensities, are closely associated with cerebral autoregulation (CA) function. Therefore, understanding the regulatory mechanism of CA in patients with CSVD is of great significance for delaying the further development of CSVD, improving cerebral ischemia and cognitive impairment. This article reviews the correlation and mechanism between CA and CSVD.

Objective:To investigate the effect of abdominal circumference on intestinal radiation dose volume and acute intestinal toxicity in pelvic intensity modulated radiation therapy for rectal cancer.Methods:A total of 150 patients with locally advanced rectal cancer (LARC) who received adjuvant and neoadjuvant concurrent chemoradiotherapy at the Affiliated Cancer Hospital of Guizhou Medical University from March 2023 to January 2025 were enrolled, including 82 cases of adjuvant radiotherapy and 68 cases of neoadjuvant radiotherapy. All patients underwent radiotherapy CT simulation positioning in the standard mode of prone position with abdominal board padding and bladder filling. Intestinal toxicity was categorized as a binary variable based on the occurrence of ≥2 grade acute intestinal toxicity. Linear and logistic regression models were used to analyze the factors influencing intestinal radiation dose volumes (V 10, V 20, V 30, V 40) and acute intestinal toxicity in LARC patients. Generalized additive models and piecewise linear and logistic regression analyses were employed to examine the threshold effects of abdominal circumference on intestinal radiation dose volumes and acute intestinal toxicity. The threshold value for abdominal circumference was determined based on the upper limit of the 95% CI for the threshold. A difference test was used to validate the differences in intestinal radiation dose volume and acute intestinal toxicity between small and medium-to-large abdominal circumferences. Results:Univariate analysis showed that, gender, body mass, abdominal circumference, planning target volume (PTV), intestinal volume were all influencing factors for the radiation dose volumes (V 10, V 20, V 30, V 40) of each intestinal segment of patients with LARC undergoing adjuvant radiotherapy (all P<0.05). Body mass, abdominal circumference, intestinal volume were all influencing factors for the radiation dose volumes (V 10, V 20, V 30, V 40) of each intestinal segment of patients with LARC undergoing neoadjuvant radiotherapy (all P<0.05). Body mass index (BMI), abdominal circumference, intestinal volume and individual intestinal radiation volumes (V 10, V 20, V 30, V 40) were all influencing factors for the acute intestinal toxicity of patients with LARC undergoing adjuvant radiotherapy (all P<0.05). Body mass, BMI, abdominal circumference, multiple intestinal radiation dose volumes (V 20, V 30, V 40) were all influencing factors for the acute intestinal toxicity of patients with LARC undergoing neoadjuvant radiotherapy (all P<0.05). Multivariate analysis showed that, abdominal circumference (V 10: β=-1.01, 95% CI: -1.68--0.33, P=0.004; V 20: β=-0.94, 95% CI: -1.28--0.60, P<0.001; V 30: β=-0.58, 95% CI: -0.82--0.34, P<0.001; V 40: β=-0.41, 95% CI: -0.60--0.23, P<0.001) was an independent influencing factor for the radiation dose volume of each intestinal segment of patients with LARC undergoing adjuvant radiotherapy. Abdominal circumference (V 10: β=-0.92, 95% CI: -1.62--0.22, P=0.010; V 20: β=-0.84, 95% CI: -1.11--0.57, P<0.001; V 30: β=-0.42, 95% CI: -0.57--0.28, P<0.001; V 40: β=-0.30, 95% CI: -0.41--0.19, P<0.001) was an independent influencing factor for the radiation dose volume of each intestinal segment of patients with LARC undergoing neoadjuvant radiotherapy. Abdominal circumference ( OR=0.86, 95% CI: 0.78-0.95, P=0.002) was an independent influencing factor for the acute intestinal toxicity of patients with LARC undergoing adjuvant radiotherapy. Abdominal circumference ( OR=0.87, 95% CI: 0.79-0.96, P=0.004) was an independent influencing factor for the acute intestinal toxicity of patients with LARC undergoing neoadjuvant radiotherapy. The generalized additive model revealed a nonlinear relationship between abdominal circumference and intestinal radiation dose volume and acute intestinal toxicity of adjuvant radiotherapy patients. Further segmented regression analysis results showed that there was a threshold effect between abdominal circumference and intestinal radiation dose volume (V 10, V 20, V 30, V 40) and acute intestinal toxicity. The inflection point values between abdominal circumference and intestinal radiation dose volume V 10, V 20, V 30, V 40 in LARC patients undergoing adjuvant radiotherapy were all 71.9 cm; the inflection point values between abdominal circumference and the intestinal radiation dose volume V 10, V 20, V 30, V 40 in LARC patients undergoing neoadjuvant radiotherapy were 69.0, 69.0, 69.0, 68.6 cm, respectively; The inflection point values between abdominal circumference and acute intestinal toxicity in LARC patients undergoing adjuvant radiotherapy and neoadjuvant radiotherapy were 71.9, 69.0 cm, respectively. Based on the upper limit of the 95% CI threshold, the cutoff values for small and medium-to-large abdominal circumferences for patients undergoing adjuvant and neoadjuvant radiotherapy were set at 76.1, 71.9 cm, respectively. In patients undergoing adjuvant radiotherapy, the levels of intestinal radiation dose volume V 10 [ (7.65±2.29) cm 3vs. (5.88±2.68) cm 3, t=2.76, P=0.007], V 20 [ (4.28±1.27) cm 3vs. (2.72±1.31) cm 3, t=4.81, P<0.001], V 30 [ (2.42±1.07) cm 3vs. (1.37±0.76) cm 3, t=4.95, P<0.001], V 40 [ (1.69±0.74) cm 3vs. (0.92±0.58) cm 3, t=4.93, P<0.001] in the small abdominal circumference group ( n=22) were significantly higher than those in patients with medium-to-large abdominal circumferences ( n=60) ; In patients undergoing neoadjuvant radiotherapy, patients with small abdominal circumferences ( n=11) had significantly higher V 20 [ (3.09±0.84) cm 3vs. (2.28±1.17) cm 3, t=2.17, P=0.033], V 30 [1.44 (1.22, 1.53) cm 3vs. 0.91 (0.56, 1.22) cm 3, Z=-3.04, P=0.002], V 40 [0.93 (0.84, 1.09) cm 3vs. 0.44 (0.30, 0.81) cm 3, Z=-3.19, P=0.001] than patients with medium-to-large abdominal circumferences ( n=57). In patients receiving adjuvant radiotherapy and neoadjuvant radiotherapy, there were statistically significant differences in acute intestinal toxicity between patients with small abdominal circumferences and with medium-to-large abdominal circumferences ( χ2=10.46, P=0.001; χ2=8.13, P=0.004) . Conclusions:In the standard mode (prone position with abdominal board padding and bladder filling), abdominal circumference is an independent factor influencing the intestinal radiation dose volume and acute intestinal toxicity in rectal cancer radiotherapy patients. There is a significant non-linear threshold effect between abdominal circumference and different levels of intestinal radiation dose volume and acute intestinal toxicity. The impact of abdominal circumference on intestinal radiation dose volume and toxicity differs significantly before and after the inflection point value. Patients with smaller abdominal circumferences not only fail to achieve the expected benefits under the current standard radiotherapy regimen but also face higher risks of intestinal radiation dose volume and toxicity.