This study explored how the human cortical folding pattern composed of convex gyri and concave sulci affected single-subject morphological brain networks, which are becoming an important method for studying the human brain connectome. We found that gyri-gyri networks exhibited higher morphological similarity, lower small-world parameters, and lower long-term test-retest reliability than sulci-sulci networks for cortical thickness- and gyrification index-based networks, while opposite patterns were observed for fractal dimension-based networks. Further behavioral association analysis revealed that gyri-gyri networks and connections between gyral and sulcal regions significantly explained inter-individual variance in Cognition and Motor domains for fractal dimension- and sulcal depth-based networks. Finally, the clinical application showed that only sulci-sulci networks exhibited morphological similarity reductions in major depressive disorder for cortical thickness-, fractal dimension-, and gyrification index-based networks. Taken together, these findings provide novel insights into the constraint of the cortical folding pattern to the network organization of the human brain.
Humans ; Cerebral Cortex/anatomy & histology* ; Male ; Female ; Magnetic Resonance Imaging ; Adult ; Connectome/methods* ; Young Adult ; Nerve Net/anatomy & histology* ; Neural Pathways ; Depressive Disorder, Major/diagnostic imaging*

Objective:To analyze the differences in clinicopathological features of colon cancers and survival between patients with right- versus left-sided colon cancers.Methods:This was a retrospective cohort study. Information on patients with colon cancer from January 2016 to August 2020 was collected from the prospective registry database at Peking Union Medical College Hospital . Primary tumors located in the cecum, ascending colon, and proximal two‐thirds of the transverse colon were defined as right-sided colon cancers (RCCs), whereas primary tumors located in the distal third of the transverse colon, descending colon, or sigmoid colon were defined as left‐sided colon cancers (LCCs). Clinicopathological features were compared using the χ 2 test or Mann‐Whitney U test. Survival was estimated by Kaplan‐Meier curves and the log‐rank test. Factors that differed significantly between the two groups were identified by multivariate survival analyses performed with the Cox proportional hazards function. One propensity score matching was performed to eliminate the effects of confounding factors. Results:The study cohort comprised 856 patients, with TNM Stage I disease, 391 (45.7%) with Stage II, and 336 (39.3%) with Stage III, including 442 (51.6%) with LCC and 414 (48.4%) with RCC and 129 (15.1%). Defective mismatch repair (dMMR) was identified in 139 patients (16.2%). Compared with RCC, the proportion of men (274/442 [62.0%] vs. 224/414 [54.1%], χ 2=5.462, P=0.019), body mass index (24.2 [21.9, 26.6] kg/m 2 vs. 23.2 [21.3, 25.5] kg/m 2, U=78,789.0, P<0.001), and well/moderately differentiated cancer (412/442 [93.2%] vs. 344/414 [83.1%], χ 2=22.266, P<0.001) were higher in the LCC than the RCC group. In contrast, the proportion of dMMR (40/442 [9.0%] vs. 99/414 [23.9%], χ 2=34.721, P<0.001) and combined vascular invasion (106/442[24.0%] vs. 125/414[30.2%], χ 2=4.186, P=0.041) were lower in the LCC than RCC group. The median follow‐up time for all patients was 48 (range 33, 59) months. The log‐rank test revealed no significant differences in disease-free survival (DFS) ( P=0.668) or overall survival (OS) ( P=0.828) between patients with LCC versus RCC. Cox proportional hazards model showed that dMMR was significantly associated with a longer DFS (HR=0.419, 95%CI: 0.204?0.862, P=0.018), whereas a higher proportion of T3‐4 (HR=2.178, 95%CI: 1.089?4.359, P=0.028), N+ (HR=2.126, 95%CI: 1.443?3.133, P<0.001), and perineural invasion (HR=1.835, 95%CI: 1.115?3.020, P=0.017) were associated with poor DFS. Tumor location was not associated with DFS or OS (all P>0.05). Subsequent analysis showed that RCC patients with dMMR had longer DFS than did RCC patients with pMMR (HR=0.338, 95%CI: 0.146?0.786, P=0.012). However, the difference in OS between the two groups was not statistically significant (HR=0.340, 95%CI:0.103?1.119, P=0.076). After propensity score matching for independent risk factors for DFS, the log‐rank test revealed no significant differences in DFS ( P=0.343) or OS ( P=0.658) between patients with LCC versus RCC, whereas patient with dMMR had better DFS ( P=0.047) and OS ( P=0.040) than did patients with pMMR. Conclusions:Tumor location is associated with differences in clinicopathological features; however, this has no impact on survival. dMMR status is significantly associated with longer survival: this association may be stronger in RCC patients.

Objective:To explore the impact on safety and prognosis in patients with right-sided colon cancer participating in surgical clinical research.Methods:This retrospective cohort study utilized data from a randomized controlled trial (RELARC study) conducted by the colorectal surgery group at Peking Union Medical College Hospital in which laparoscopic complete mesocolic excision (CME) was compared with D2 radical resection for the management of right-sided colon cancer. The eligibility criteria were age 18–75 years, biopsy-proven colon adenocarcinoma, tumor located between the cecum and right 1/3 of the transverse colon, enhanced chest, abdomen, and pelvic CT scans suggesting tumor stage T2–T4N0M0 or TanyN+ M0, and having undergone radical surgical treatment from January 2016 to December 2019. Exclusion factors included multiple primary colorectal cancers, preoperative stage T1N0 or enlarged central lymph nodes, tumor involving surrounding organs requiring their resection, definite distant metastasis or otherwise unable to undergo R0 resection, history of any other malignant tumors within previous 5 years, intestinal obstruction, perforation, or gastrointestinal bleeding requiring emergency surgery, and assessed as unsuitable for laparoscopic surgery. Patients who had participated in the RELARC study were included in the RELARC group, whereas those who met the inclusion criteria but refused to participate in the RELAEC study were included in the control group. The main indicators studied were the patient's baseline data, surgery and perioperative conditions, pathological characteristics, adjuvant treatment, and postoperative follow-up (including average frequency of follow-up within the first 3 years) and survival (including 3-year disease-free survival rate (DFS) and 3-year overall survival rate (OS). Differences in these indicators between the RELARC and control groups were compared.Results:The study cohort comprised 290 patients, 173 in the RELARC group (RELARC-CME group, 82; RELARC-D2 group, 91) and 117 in the control group (CME control group, 72; D2 control group, 45). There was a significantly higher proportion of overweight patients (BMI ≥24 kg/m 2) in the RELARC-CME than in the CME control group (67.1% [55/82] vs. 33.3% [24/72], χ 2=17.469, P<0.001). There were no other statistically significant differences in baseline characteristics (all P>0.05). No significant disparities were found between the CME and D2 groups in terms of operation duration, intraoperative blood loss, rate of conversion to open surgery, combined organ resection, intraoperative blood transfusion, or intraoperative complications (all P>0.05). There was a trend toward Clavien–Dindo grade II or higher postoperative complications in the RELARC-CME group (24.4% [20/82]) than in the CME control group (18.1% [13/72]); however, this difference was not statistically significant (χ 2=0.914, P=0.339). Similarly, the difference in this rate did not differ significantly between the RELARC-D2 group (25.3% [23/91]) and D2 control group (24.4% [11/45], χ 2=0.011, P=0.916). The median duration of postoperative follow-up was significantly shorter in the RELARC groups than in the corresponding control groups. Specifically, the median duration of follow-up was 4.5 (4.5, 4.5) months in the RELARC-CME and 7.2 (6.0, 9.0) months in the CME control group ( Z=-10.608, P<0.001). Similarly, the median duration of follow-up was 4.5 (4.5, 4.5) months in the RELARC-D2 group as opposed to 8.3 (6.6, 9.0) months in the D2 control group ( Z=-10.595, P<0.001). The 3-year DFS rate (91.5%) and OS rate (96.3%) tended to be higher in the RELARC-CME group than in the CME control group (84.7% and 90.3%, respectively). The 3-year DFS rate (87.9%) and OS rate (96.7%) tended to be higher in the RELARC-D2 group than in the D2 control group (81.8% and 88.6%, respectively); however, these differences were not statistically significant (all P>0.05). Subgroup analysis according to pathological stage revealed that patients in the RELARC-D2 group with pN0 stage achieved a significantly superior 3-year OS rate than did those in the D2 control group (100% vs. 88.9%, P=0.008). We identified no statistically significant differences in survival rates between the remaining subgroups (all P>0.05). Conclusions:A high-quality surgical clinical trial with close follow-up can achieve perioperative safety and a trend toward improved survival outcomes.

Objective:To investigate the clinical characteristics of brain metastases after radical surgery for locally advanced rectal cancer (LARC).Methods:The clinical characteristics of LARC with brain metastases treated in the Department of General Surgery, Peking Union Medical College Hospital from 2013 to 2023 were retrospectively analyzed. The inclusion criteria were rectal adenocarcinoma within 15 cm of the anal verge and having undergone radical surgery, and the exclusion criterion was primary malignant tumor of the brain. The main outcomes were overall survival (OS), disease-free survival (DFS), and disease-specific overall survival (determined as the interval between occurrence of brain metastasis to death from any causes). The Kaplan–Meier method was used for survival analysis.Results:We identified 4500 patients with LARC, 20 (0.4%) of whom had brain metastases. The mean age of patients with brain metastases was 63.8±9.3 years. They comprised five women and 15 men. The brain was the first site of metastasis in four patients (20%) whereas 18 patients had heterochronous extracranial metastases before brain metastasis. Two patients also had multi-organ metastases. The most common manifestations of brain metastases were dizziness and headache (five patients, 25%), sudden onset of limb weakness (four, 20%), sudden speech impairment (two, 10%), and polyopia (two, 10%). The metastases were diagnosed during follow-up in three patients (15%). Four of the patients were asymptomatic (20%). Treatment approaches included surgical resection (six patients, 30%), chemoradiotherapy (nine, 45%), and palliative (five, 25%). The median follow-up time was 45.5 (4–112) months until October 2023. 1y-OS, 3y-OS, and 5y-OS were 95.0%, 62.9%, and 43.3%, respectively. 1y-DFS, 3y-DFS, and 5y-DFS were 55.0%, 25.0%, and 5.0%, respectively. With brain metastasis as the starting point, the median duration of survival was 16 (10.2–21.8) months.Conclusion:The incidence of brain metastasis is relatively low in patients with LARC, who often have multiple synchronous extracranial metastases. Brain metastases lack specific manifestations and more often occur in male patients. Surgical intervention or combined radiotherapy and chemotherapy may improve disease-specific survival to a certain extent. However, the overall prognosis remains poor.

Objective:To investigate the interactive effect of mismatch repair (MMR) protein status and adverse clinicopathological features on prognosis of stage Ⅰ-Ⅲ colon cancer.Methods:The retrospective cohort study was conducted. The clinicopathological data of 1 650 patients with colon cancer of stage Ⅰ-Ⅲ who were admitted to 7 hospitals in China from January 2016 to December 2017 were collected. There were 963 males and 687 females, aged 62(53,71)years. Patients were classified as 230 cases of MMR deficiency (dMMR) and 1 420 cases of MMR proficiency (pMMR) based on their MMR protein status. Observation indicators: (1) comparison of clinicopathological characteristics between patients of different MMR protein status; (2) analysis of factors affecting the survival outcomes of patients of dMMR; (3) analysis of factors affecting the survival outcomes of patients of pMMR; (4) interaction analysis of MMR and adverse clinicopathological features on survival outcomes. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was conducted using the Mann-Whitney U test. The random forest interpolation method was used for missing values in data interpolation. Univariate analysis was conducted using the COX proportional risk regression model, and multivariate analysis was conducted using the COX stepwise regression with forward method. The coefficient of multiplication interaction effect was obtained using the interaction term coefficient of COX proportional risk regression model. Evaluation of additive interaction effects was conducted using the relative excess risk due to interaction ( RERI). Results:(1) Comparison of clinicopathological characteristics between patients of different MMR protein status. There were significant differences in age, T staging, the number of lymph node harvest, the number of lymph node harvest <12, high grade tumor between patients of dMMR and pMMR ( P<0.05). (2) Analysis of factors affecting the survival outcomes of patients of dMMR. Results of multivariate analysis showed that T staging, N staging, the number of lymph node harvest <12 were independent factors affecting the disease-free survival (DFS) of colon cancer patients of dMMR ( hazard ratio=3.548, 2.589, 6.702, 95% confidence interval as 1.460-8.620, 1.064-6.301, 1.886-23.813, P<0.05). Age and N staging were independent factors affecting the overall survival (OS) of colon cancer patients of dMMR ( hazard ratio=1.073, 10.684, 95% confidence interval as 1.021-1.126, 2.311-49.404, P<0.05). (3) Analysis of factors affecting the survival outcomes of patients of pMMR. Results of multivariate analysis showed that age, T staging, N staging, vascular tumor thrombus were independent factors affecting the DFS of colon cancer patients of pMMR ( hazard ratio=1.018, 2.214, 2.598, 1.549, 95% confidence interval as 1.006-1.030, 1.618-3.030, 1.921-3.513, 1.118-2.147, P<0.05). Age, T staging, N staging, high grade tumor were independent factors affecting the OS of colon cancer patients of pMMR ( hazard ratio=1.036, 2.080, 2.591, 1.615, 95% confidence interval as 1.020-1.052, 1.407-3.075, 1.791-3.748, 1.114-2.341, P<0.05). (4) Interaction analysis of MMR and adverse clinicopathological features on survival outcomes. Results of interaction analysis showed that the multiplication interaction effect between the number of lymph node harvest <12 and MMR protein status was significant on DFS of colon cancer patients ( hazard ratio=3.923, 95% confidence interval as 1.057-14.555, P<0.05). The additive interaction effects between age and MMR protein status, between high grade tumor and MMR protein status were significant on OS of colon cancer patients ( RERI=-0.033, -1.304, 95% confidence interval as -0.049 to -0.018, -2.462 to -0.146). Conclusions:There is an interaction between the MMR protein status and the adverse clinicopathological features (the number of lymph node harvest <12, high grade tumor) on prognosis of colon cancer patients of stage Ⅰ-Ⅲ. In patients of dMMR, the number of lymph node harvest <12 has a stronger predictive effect on poor prognosis. In patients of pMMR, the high grade tumor has a stronger predictive effect on poor prognosis.

Objective:To analyze the differences in clinicopathological features of colon cancers and survival between patients with right- versus left-sided colon cancers.Methods:This was a retrospective cohort study. Information on patients with colon cancer from January 2016 to August 2020 was collected from the prospective registry database at Peking Union Medical College Hospital . Primary tumors located in the cecum, ascending colon, and proximal two‐thirds of the transverse colon were defined as right-sided colon cancers (RCCs), whereas primary tumors located in the distal third of the transverse colon, descending colon, or sigmoid colon were defined as left‐sided colon cancers (LCCs). Clinicopathological features were compared using the χ 2 test or Mann‐Whitney U test. Survival was estimated by Kaplan‐Meier curves and the log‐rank test. Factors that differed significantly between the two groups were identified by multivariate survival analyses performed with the Cox proportional hazards function. One propensity score matching was performed to eliminate the effects of confounding factors. Results:The study cohort comprised 856 patients, with TNM Stage I disease, 391 (45.7%) with Stage II, and 336 (39.3%) with Stage III, including 442 (51.6%) with LCC and 414 (48.4%) with RCC and 129 (15.1%). Defective mismatch repair (dMMR) was identified in 139 patients (16.2%). Compared with RCC, the proportion of men (274/442 [62.0%] vs. 224/414 [54.1%], χ 2=5.462, P=0.019), body mass index (24.2 [21.9, 26.6] kg/m 2 vs. 23.2 [21.3, 25.5] kg/m 2, U=78,789.0, P<0.001), and well/moderately differentiated cancer (412/442 [93.2%] vs. 344/414 [83.1%], χ 2=22.266, P<0.001) were higher in the LCC than the RCC group. In contrast, the proportion of dMMR (40/442 [9.0%] vs. 99/414 [23.9%], χ 2=34.721, P<0.001) and combined vascular invasion (106/442[24.0%] vs. 125/414[30.2%], χ 2=4.186, P=0.041) were lower in the LCC than RCC group. The median follow‐up time for all patients was 48 (range 33, 59) months. The log‐rank test revealed no significant differences in disease-free survival (DFS) ( P=0.668) or overall survival (OS) ( P=0.828) between patients with LCC versus RCC. Cox proportional hazards model showed that dMMR was significantly associated with a longer DFS (HR=0.419, 95%CI: 0.204?0.862, P=0.018), whereas a higher proportion of T3‐4 (HR=2.178, 95%CI: 1.089?4.359, P=0.028), N+ (HR=2.126, 95%CI: 1.443?3.133, P<0.001), and perineural invasion (HR=1.835, 95%CI: 1.115?3.020, P=0.017) were associated with poor DFS. Tumor location was not associated with DFS or OS (all P>0.05). Subsequent analysis showed that RCC patients with dMMR had longer DFS than did RCC patients with pMMR (HR=0.338, 95%CI: 0.146?0.786, P=0.012). However, the difference in OS between the two groups was not statistically significant (HR=0.340, 95%CI:0.103?1.119, P=0.076). After propensity score matching for independent risk factors for DFS, the log‐rank test revealed no significant differences in DFS ( P=0.343) or OS ( P=0.658) between patients with LCC versus RCC, whereas patient with dMMR had better DFS ( P=0.047) and OS ( P=0.040) than did patients with pMMR. Conclusions:Tumor location is associated with differences in clinicopathological features; however, this has no impact on survival. dMMR status is significantly associated with longer survival: this association may be stronger in RCC patients.

Objective:To explore the impact on safety and prognosis in patients with right-sided colon cancer participating in surgical clinical research.Methods:This retrospective cohort study utilized data from a randomized controlled trial (RELARC study) conducted by the colorectal surgery group at Peking Union Medical College Hospital in which laparoscopic complete mesocolic excision (CME) was compared with D2 radical resection for the management of right-sided colon cancer. The eligibility criteria were age 18–75 years, biopsy-proven colon adenocarcinoma, tumor located between the cecum and right 1/3 of the transverse colon, enhanced chest, abdomen, and pelvic CT scans suggesting tumor stage T2–T4N0M0 or TanyN+ M0, and having undergone radical surgical treatment from January 2016 to December 2019. Exclusion factors included multiple primary colorectal cancers, preoperative stage T1N0 or enlarged central lymph nodes, tumor involving surrounding organs requiring their resection, definite distant metastasis or otherwise unable to undergo R0 resection, history of any other malignant tumors within previous 5 years, intestinal obstruction, perforation, or gastrointestinal bleeding requiring emergency surgery, and assessed as unsuitable for laparoscopic surgery. Patients who had participated in the RELARC study were included in the RELARC group, whereas those who met the inclusion criteria but refused to participate in the RELAEC study were included in the control group. The main indicators studied were the patient's baseline data, surgery and perioperative conditions, pathological characteristics, adjuvant treatment, and postoperative follow-up (including average frequency of follow-up within the first 3 years) and survival (including 3-year disease-free survival rate (DFS) and 3-year overall survival rate (OS). Differences in these indicators between the RELARC and control groups were compared.Results:The study cohort comprised 290 patients, 173 in the RELARC group (RELARC-CME group, 82; RELARC-D2 group, 91) and 117 in the control group (CME control group, 72; D2 control group, 45). There was a significantly higher proportion of overweight patients (BMI ≥24 kg/m 2) in the RELARC-CME than in the CME control group (67.1% [55/82] vs. 33.3% [24/72], χ 2=17.469, P<0.001). There were no other statistically significant differences in baseline characteristics (all P>0.05). No significant disparities were found between the CME and D2 groups in terms of operation duration, intraoperative blood loss, rate of conversion to open surgery, combined organ resection, intraoperative blood transfusion, or intraoperative complications (all P>0.05). There was a trend toward Clavien–Dindo grade II or higher postoperative complications in the RELARC-CME group (24.4% [20/82]) than in the CME control group (18.1% [13/72]); however, this difference was not statistically significant (χ 2=0.914, P=0.339). Similarly, the difference in this rate did not differ significantly between the RELARC-D2 group (25.3% [23/91]) and D2 control group (24.4% [11/45], χ 2=0.011, P=0.916). The median duration of postoperative follow-up was significantly shorter in the RELARC groups than in the corresponding control groups. Specifically, the median duration of follow-up was 4.5 (4.5, 4.5) months in the RELARC-CME and 7.2 (6.0, 9.0) months in the CME control group ( Z=-10.608, P<0.001). Similarly, the median duration of follow-up was 4.5 (4.5, 4.5) months in the RELARC-D2 group as opposed to 8.3 (6.6, 9.0) months in the D2 control group ( Z=-10.595, P<0.001). The 3-year DFS rate (91.5%) and OS rate (96.3%) tended to be higher in the RELARC-CME group than in the CME control group (84.7% and 90.3%, respectively). The 3-year DFS rate (87.9%) and OS rate (96.7%) tended to be higher in the RELARC-D2 group than in the D2 control group (81.8% and 88.6%, respectively); however, these differences were not statistically significant (all P>0.05). Subgroup analysis according to pathological stage revealed that patients in the RELARC-D2 group with pN0 stage achieved a significantly superior 3-year OS rate than did those in the D2 control group (100% vs. 88.9%, P=0.008). We identified no statistically significant differences in survival rates between the remaining subgroups (all P>0.05). Conclusions:A high-quality surgical clinical trial with close follow-up can achieve perioperative safety and a trend toward improved survival outcomes.

Objective:To investigate the clinical characteristics of brain metastases after radical surgery for locally advanced rectal cancer (LARC).Methods:The clinical characteristics of LARC with brain metastases treated in the Department of General Surgery, Peking Union Medical College Hospital from 2013 to 2023 were retrospectively analyzed. The inclusion criteria were rectal adenocarcinoma within 15 cm of the anal verge and having undergone radical surgery, and the exclusion criterion was primary malignant tumor of the brain. The main outcomes were overall survival (OS), disease-free survival (DFS), and disease-specific overall survival (determined as the interval between occurrence of brain metastasis to death from any causes). The Kaplan–Meier method was used for survival analysis.Results:We identified 4500 patients with LARC, 20 (0.4%) of whom had brain metastases. The mean age of patients with brain metastases was 63.8±9.3 years. They comprised five women and 15 men. The brain was the first site of metastasis in four patients (20%) whereas 18 patients had heterochronous extracranial metastases before brain metastasis. Two patients also had multi-organ metastases. The most common manifestations of brain metastases were dizziness and headache (five patients, 25%), sudden onset of limb weakness (four, 20%), sudden speech impairment (two, 10%), and polyopia (two, 10%). The metastases were diagnosed during follow-up in three patients (15%). Four of the patients were asymptomatic (20%). Treatment approaches included surgical resection (six patients, 30%), chemoradiotherapy (nine, 45%), and palliative (five, 25%). The median follow-up time was 45.5 (4–112) months until October 2023. 1y-OS, 3y-OS, and 5y-OS were 95.0%, 62.9%, and 43.3%, respectively. 1y-DFS, 3y-DFS, and 5y-DFS were 55.0%, 25.0%, and 5.0%, respectively. With brain metastasis as the starting point, the median duration of survival was 16 (10.2–21.8) months.Conclusion:The incidence of brain metastasis is relatively low in patients with LARC, who often have multiple synchronous extracranial metastases. Brain metastases lack specific manifestations and more often occur in male patients. Surgical intervention or combined radiotherapy and chemotherapy may improve disease-specific survival to a certain extent. However, the overall prognosis remains poor.

Objective:To investigate the incidence and influencing factors of anastomotic leakage after laparoscopic anterior resection for rectal cancer.Methods:The retrospective case-control study was conducted. The clinicopathological data of 804 patients with rectal cancer who were admitted to Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from January 2017 to December 2019 were collected. There were 521 male and 283 female, aged 63(range, 27-94)years. All 804 patients underwent laparoscopic anterior resection for rectal cancer. Observation indicators: (1) surgical situations; (2) incidence of postoperative anastomotic leakage; (3) follow-up; (4) influencing factors of postoperative anastomotic leakage; (5) subgroup analysis. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribu-tion were represented as 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. Univariate analysis was conducted using the chi-square test or independent sample t test. Factors with P≤0.2 in univariate analysis were included in multivariate Logistic regression analysis. Results:(1) Surgical situations. All 804 patients underwent laparoscopic radical resection of upper and middle rectal cancer successfully, with the operation time and volume of intraoperative blood loss as 135(range, 118-256)minutes and 30(range, 5-350)mL. All 804 patients completed end-to-end colon rectal anastomosis, including 287 patients with reinforced sutures at the anastomotic site, and 517 patients with routine anastomosis. (2) Incidence of postoperative anastomotic leakage. Of the 804 patients, 40 patients had postoperative anastomotic leakage, with the incidence rate as 4.98%(40/804). (3) Follow-up. All 804 patients were followed up for 32(range, 6-49)months. None of patient died during the perioperative period. (4) Influencing factors of postoperative anastomotic leakage. Results of multivariate analysis showed that unreinforced suture at the anastomotic site was an independent risk factor for postoperative anastomotic leakage ( odds ratio=2.78, 95% confidence interval as 1.21-6.37, P<0.05). (5) Subgroup analysis. Of the 804 patients, 202 patients received neoadjuvant therapy and 602 patients did not receive neoadjuvant therapy. Of the 602 patients who did not receive neo-adjuvant therapy, cases with postoperative anastomotic leakage was 6 in the 253 patients with reinforced sutures, versus 21 in the 349 patients with routine sutures, showing a significant difference between them ( χ2=4.56, P<0.05). Conclusion:Unreinforced anastomosis at the anasto-motic site is an independent risk factor for anastomotic leakage after laparoscopic anterior rectal resection, especially for rectal cancer patients without neoadjuvant radiochemotherapy.