Objective:To explore the prognosis after radical resection for stage Ⅰ gastric cancer and the application value of adjuvant chemotherapy.Methods:The retrospective cohort study was conducted. The clinicopathological data of 3 353 patients with stage Ⅰ gastric cancer who were admitted to Fudan University Shanghai Cancer Center from January 2000 to December 2022 were collected. There were 2 369 males and 984 females, aged 60(range, 21-91) years. All patients underwent radical R 0 resection. Observation indicators: (1) clinicopathological characteristics of patients; (2) influencing factors for postoperative prognosis of patients; (3) prognostic analysis of patients; (4) construction and validation of a predictive model for the efficacy of postoperative adjuvant chemotherapy. Comparison of count data between groups was conducted using the chi-square test. Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. The Kaplan-Meier method was used to calculate survival rates and draw survival curves, and the Log-rank test was used for survival analysis. Based on the multivariate analysis result, a nomogram prediction model was constructed to predict survival benefit. Results:(1) Clinicopatho-logical characteristics of patients. The highly, moderately, and poorly differentiated tumors were observed in 16, 234, 396 cases of 646 patients aged <50 years and 279, 1 617, 811 cases of 2 707 pati-ents aged ≥50 years, respectively, showing a significant difference in degree of tumor differentiation between them ( P<0.05). For 297 patients in stage T1N1M0, cases aged <50 years and ≥50 years were 71 and 226, cases of males and females were 184 and 113, cases with negative and positive vascular invasion were 37 and 260, cases with negative and positive nerve invasion were 275 and 22, cases without and with postoperative adjuvant chemotherapy were 222 and 75, respectively. The above indicators for 678 patients in stage T2N0M0 105, 573, 533, 145, 517, 161, 526, 152, 563, 115, respectively. There were significant differences in the above indicators between the two groups ( P<0.05). (2) Influencing factors for postoperative prognosis of patients. Results of multivariate analysis showed that age ≥50 years, stage T2, moderately differentiated tumor, the number of lymph nodes dissected <16, positive vascular invasion, carcinoembryonic antigen (CEA) ≥5 μg/L, and CA19-9 ≥37 U/mL were independent risk factors for disease-free survival (DFS) after surgery for stage Ⅰ gastric cancer ( hazard ratio=4.600, 1.555, 1.835, 1.362, 1.451, 1.571, 2.134, 95% confidence interval as 2.806-7.541, 1.205-2.006, 1.016-3.314, 1.059-1.753, 1.057-1.993, 1.100-2.243, 1.257-3.625, P<0.05). Age ≥50 years, stage T2, the number of lymph nodes dissected <16, positive vascular invasion, CEA ≥5 μg/L, and CA19-9 ≥37 U/mL were independent risk factors for overall survival (OS) after surgery for stage Ⅰ gastric cancer ( hazard ratio=5.208, 1.597, 1.373, 1.520, 1.464, 2.356, 95% confidence interval as 3.028-8.955, 1.231-2.072, 1.060-1.777, 1.099-2.104, 1.004-2.134, 1.385-4.009, P<0.05). Postoperative adjuvant chemotherapy was an independent protective factor for both DFS and OS after surgery for stage I gastric cancer ( hazard ratio=0.361 0.297, 95% confidence interval as 0.177-0.736, 0.131-0.674, P<0.05). (3) Prognostic analysis of patients. According to the results of multi-variate analysis, among 3 353 patients, there were significant differences in 5-year DFS rate and 10-year OS rate between patients aged <50 years and ≥50 years ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients in TNM stage ⅠA and ⅠB ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients in stage T1N0M0, T1N1M0, T2N0M0 ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients with the highly, moderately, and poorly differentiated tumors ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients with the number of lymph lodes dissected <16 and ≥16 ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate between patients with negative and positive vascular invasion ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05), among patients in stage T1N0M0, T1N1M0, T2N0M0 who received no postoperative adjuvant chemotherapy ( P<0.05). For patients in stage T1N1M0, there was no significant difference in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P>0.05).Results of stratified analysis showed that for patients aged ≥ 50 years, there were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05). For patients in stage T2N0M0, there were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05). For patients with positive vascular invasion, there were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05). (4) Construction and validation of a predictive model for the efficacy of adjuvant chemotherapy. A nomogram predictive model was constructed based on the multivariate analysis results of OS and used for calculating net benefits and distribution. Among the 3 096 patients without postoperative adjuvant chemotherapy, 1 009 cases had a predicted net benefit of >5%-10%, and 250 patients had a predicted net benefit >10%. The predicted survival analysis further verified that the predicted benefit of adjuvant chemotherapy was consistent with the prognosis of patients. Conclusions:Patients with age ≥50 years, stage T2 tumors, moderately differentiated tumor, the number of lymph nodes dissected <16, positive vascular invasion have worse survival prognosis postoperative. Postoperative adjuvant chemotherapy provides better prognosis in high-risk patients. Patients in stage T1N1M0 have lower recurrence and survival risks, of whom with 1 metastatic lymph node is more suitable for follow-up rather than postoperative adjuvant chemotherapy.

Objective:To establish the minimum number of negative lymph nodes (nLN) required for patients undergoing gastrectomy.Methods:This was a retrospective cohort study with inclusion criteria as follows: (1) radical gastrectomy; (2) histologically confirmed adenocarcinoma; (3) complete tumor staging information; and (4) known number of lymph nodes harvested. The exclusion criteria were: (1) other concurrent malignant tumors; (2) metastatic or recurrent gastric cancer; (3) initial surgery performed at another hospital; (4) preoperative neoadjuvant therapy; (5) distant metastasis; and (6) incomplete clinical data or follow-up information. Based on the above criteria, a total of 11 167 patients with gastric adenocarcinoma who underwent radical subtotal gastrectomy (RSG) or radical total gastrectomy (RTG) in the Department of Gastric Surgery, Fudan University Shanghai Cancer Center between January 1, 2000, and December 31, 2022, were included in the study. Among them, there were 7 596 cases in the RSG group and 3 571 cases in the RTG group. Restricted cubic spline (RCS) analysis was used to determine the ideal threshold for nLN for RSG and RTG patients. Survival analysis was conducted using Kaplan-Meier (KM) curves and log-rank tests, and propensity score matching (PSM) was utilized to balance parameters between two groups. Furthermore, subgroup analysis was conducted for RSG patients based on tumor location (upper, middle and lower) to determine the minimum number of nLN in each subgroup.Results:For patients who underwent RSG, the mean number of nLN was 21.9, with a median of 21. RCS analysis showed that more than 21 nLN was associated with better survival. Moreover, both pre- and post-PSM analysis confirmed that patients with nLN ≥21 had better survival benefits compared to those with nLN <21 (overall survival [OS]: P<0.001 before PSM, P=0.013 after PSM; disease-free survival [DFS]: P<0.001 before PSM, P=0.013 after PSM). For patients who underwent RTG, the mean number of nLN was 23.5, with a median of 22. Here RCS analysis indicated that more than 22 nLN was associated with better postoperative survival in RTG patients, and both pre- and post-PSM analysis confirmed that patients with nLN ≥22 had better survival benefits compared to those with nLN<22 (OS: P<0.001 both before and after PSM; DFS: P<0.001 both before and after PSM). Subgroup analysis showed that for RSG patients with tumor located in the upper part, having ≥17 nLN (OS: both P<0.001), and for RSG patients with tumor located in the middle and lower part, having ≥22 nLN (OS: both P<0.001), were associated with better prognoses. Conclusions:For patients who receive RSG, the minimal number of nLN is ideally ≥21 (upper ≥17, middle and lower ≥22). Similarly, for patients who receive RTG, the minimum number of nLN ideally is 22.

Objective:To explore the prognosis after radical resection for stage Ⅰ gastric cancer and the application value of adjuvant chemotherapy.Methods:The retrospective cohort study was conducted. The clinicopathological data of 3 353 patients with stage Ⅰ gastric cancer who were admitted to Fudan University Shanghai Cancer Center from January 2000 to December 2022 were collected. There were 2 369 males and 984 females, aged 60(range, 21-91) years. All patients underwent radical R 0 resection. Observation indicators: (1) clinicopathological characteristics of patients; (2) influencing factors for postoperative prognosis of patients; (3) prognostic analysis of patients; (4) construction and validation of a predictive model for the efficacy of postoperative adjuvant chemotherapy. Comparison of count data between groups was conducted using the chi-square test. Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. The Kaplan-Meier method was used to calculate survival rates and draw survival curves, and the Log-rank test was used for survival analysis. Based on the multivariate analysis result, a nomogram prediction model was constructed to predict survival benefit. Results:(1) Clinicopatho-logical characteristics of patients. The highly, moderately, and poorly differentiated tumors were observed in 16, 234, 396 cases of 646 patients aged <50 years and 279, 1 617, 811 cases of 2 707 pati-ents aged ≥50 years, respectively, showing a significant difference in degree of tumor differentiation between them ( P<0.05). For 297 patients in stage T1N1M0, cases aged <50 years and ≥50 years were 71 and 226, cases of males and females were 184 and 113, cases with negative and positive vascular invasion were 37 and 260, cases with negative and positive nerve invasion were 275 and 22, cases without and with postoperative adjuvant chemotherapy were 222 and 75, respectively. The above indicators for 678 patients in stage T2N0M0 105, 573, 533, 145, 517, 161, 526, 152, 563, 115, respectively. There were significant differences in the above indicators between the two groups ( P<0.05). (2) Influencing factors for postoperative prognosis of patients. Results of multivariate analysis showed that age ≥50 years, stage T2, moderately differentiated tumor, the number of lymph nodes dissected <16, positive vascular invasion, carcinoembryonic antigen (CEA) ≥5 μg/L, and CA19-9 ≥37 U/mL were independent risk factors for disease-free survival (DFS) after surgery for stage Ⅰ gastric cancer ( hazard ratio=4.600, 1.555, 1.835, 1.362, 1.451, 1.571, 2.134, 95% confidence interval as 2.806-7.541, 1.205-2.006, 1.016-3.314, 1.059-1.753, 1.057-1.993, 1.100-2.243, 1.257-3.625, P<0.05). Age ≥50 years, stage T2, the number of lymph nodes dissected <16, positive vascular invasion, CEA ≥5 μg/L, and CA19-9 ≥37 U/mL were independent risk factors for overall survival (OS) after surgery for stage Ⅰ gastric cancer ( hazard ratio=5.208, 1.597, 1.373, 1.520, 1.464, 2.356, 95% confidence interval as 3.028-8.955, 1.231-2.072, 1.060-1.777, 1.099-2.104, 1.004-2.134, 1.385-4.009, P<0.05). Postoperative adjuvant chemotherapy was an independent protective factor for both DFS and OS after surgery for stage I gastric cancer ( hazard ratio=0.361 0.297, 95% confidence interval as 0.177-0.736, 0.131-0.674, P<0.05). (3) Prognostic analysis of patients. According to the results of multi-variate analysis, among 3 353 patients, there were significant differences in 5-year DFS rate and 10-year OS rate between patients aged <50 years and ≥50 years ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients in TNM stage ⅠA and ⅠB ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients in stage T1N0M0, T1N1M0, T2N0M0 ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients with the highly, moderately, and poorly differentiated tumors ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate among patients with the number of lymph lodes dissected <16 and ≥16 ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate between patients with negative and positive vascular invasion ( P<0.05). There were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05), among patients in stage T1N0M0, T1N1M0, T2N0M0 who received no postoperative adjuvant chemotherapy ( P<0.05). For patients in stage T1N1M0, there was no significant difference in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P>0.05).Results of stratified analysis showed that for patients aged ≥ 50 years, there were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05). For patients in stage T2N0M0, there were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05). For patients with positive vascular invasion, there were significant differences in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy ( P<0.05). (4) Construction and validation of a predictive model for the efficacy of adjuvant chemotherapy. A nomogram predictive model was constructed based on the multivariate analysis results of OS and used for calculating net benefits and distribution. Among the 3 096 patients without postoperative adjuvant chemotherapy, 1 009 cases had a predicted net benefit of >5%-10%, and 250 patients had a predicted net benefit >10%. The predicted survival analysis further verified that the predicted benefit of adjuvant chemotherapy was consistent with the prognosis of patients. Conclusions:Patients with age ≥50 years, stage T2 tumors, moderately differentiated tumor, the number of lymph nodes dissected <16, positive vascular invasion have worse survival prognosis postoperative. Postoperative adjuvant chemotherapy provides better prognosis in high-risk patients. Patients in stage T1N1M0 have lower recurrence and survival risks, of whom with 1 metastatic lymph node is more suitable for follow-up rather than postoperative adjuvant chemotherapy.

Objective:To establish the minimum number of negative lymph nodes (nLN) required for patients undergoing gastrectomy.Methods:This was a retrospective cohort study with inclusion criteria as follows: (1) radical gastrectomy; (2) histologically confirmed adenocarcinoma; (3) complete tumor staging information; and (4) known number of lymph nodes harvested. The exclusion criteria were: (1) other concurrent malignant tumors; (2) metastatic or recurrent gastric cancer; (3) initial surgery performed at another hospital; (4) preoperative neoadjuvant therapy; (5) distant metastasis; and (6) incomplete clinical data or follow-up information. Based on the above criteria, a total of 11 167 patients with gastric adenocarcinoma who underwent radical subtotal gastrectomy (RSG) or radical total gastrectomy (RTG) in the Department of Gastric Surgery, Fudan University Shanghai Cancer Center between January 1, 2000, and December 31, 2022, were included in the study. Among them, there were 7 596 cases in the RSG group and 3 571 cases in the RTG group. Restricted cubic spline (RCS) analysis was used to determine the ideal threshold for nLN for RSG and RTG patients. Survival analysis was conducted using Kaplan-Meier (KM) curves and log-rank tests, and propensity score matching (PSM) was utilized to balance parameters between two groups. Furthermore, subgroup analysis was conducted for RSG patients based on tumor location (upper, middle and lower) to determine the minimum number of nLN in each subgroup.Results:For patients who underwent RSG, the mean number of nLN was 21.9, with a median of 21. RCS analysis showed that more than 21 nLN was associated with better survival. Moreover, both pre- and post-PSM analysis confirmed that patients with nLN ≥21 had better survival benefits compared to those with nLN <21 (overall survival [OS]: P<0.001 before PSM, P=0.013 after PSM; disease-free survival [DFS]: P<0.001 before PSM, P=0.013 after PSM). For patients who underwent RTG, the mean number of nLN was 23.5, with a median of 22. Here RCS analysis indicated that more than 22 nLN was associated with better postoperative survival in RTG patients, and both pre- and post-PSM analysis confirmed that patients with nLN ≥22 had better survival benefits compared to those with nLN<22 (OS: P<0.001 both before and after PSM; DFS: P<0.001 both before and after PSM). Subgroup analysis showed that for RSG patients with tumor located in the upper part, having ≥17 nLN (OS: both P<0.001), and for RSG patients with tumor located in the middle and lower part, having ≥22 nLN (OS: both P<0.001), were associated with better prognoses. Conclusions:For patients who receive RSG, the minimal number of nLN is ideally ≥21 (upper ≥17, middle and lower ≥22). Similarly, for patients who receive RTG, the minimum number of nLN ideally is 22.

Objective:To investigate the influence of neoadjuvant chemotherapy on safety and prognosis of patients undergoing multivisceral resection for gastric cancer.Methods:The pro-pensity score matching (PSM) and retrospective cohort study was conducted. The clinicopathological data of 144 patients with gastric cancer who underwent multivisceral resection in the Fudan University Shanghai Cancer Center from December 2011 to December 2020 were collected. There were 95 males and 49 females, aged (56±13)years. Of 144 patients, 27 cases undergoing neoadjuvant chemotherapy and postoperative adjuvant chemotherapy were divided into the neoadjuvant chemotherapy group, and 117 cases undergoing postoperative adjuvant chemotherapy were divided into the adjuvant chemotherapy group. Observation indicators: (1) PSM and comparison of general data of patients between the two groups after matching; (2) surgical and postoperative conditions; (3) prognosis. PSM was done by the 1∶1 nearest neighbor matching method, with the caliper setting as 0.02. Measurement data with normal distribution were expressed as Mean± SD. Measurement data with skewed distribution were expressed as M(range), and comparison between groups was conducted using the rank sum test. Count data were expressed as absolute numbers, comparison between groups was conducted using the chi-square test. Comparison of ordinal data was conducted using the non-parameter test. The Kaplan-Meier method was used to draw survival curves and calculate survival rate, and the Log-Rank test was used for survival analysis. Results:(1) PSM and comparison of general data of patients between the two groups after matching. Of 144 patients, 46 cases were successfully matched, including 23 cases in the neoadjuvant chemotherapy group and 23 cases in the adjuvant chemotherapy group, respectively. The elimination of preoperative hemoglobin, clinical TNM staging confounding bias ensured comparability between the two groups after PSM. (2) Surgical and postoperative conditions. Of 46 patients, 26 cases underwent gastrectomy with one organ resection, 16 cases underwent gastrectomy with two organs resection, and 4 cases underwent gastrectomy with three organs resection. Of the patients with multivisceral resection, the proportion of patients undergoing combined splenectomy, pancreatectomy, colon resection, liver resection, and small intes-tinal resection was 69.6%(32/46), 39.1%(18/46), 32.6%(15/46), 8.7%(4/46), 2.2%(1/46), respectively. Cases with D 1 lymph node dissection, cases with D 2 lymph node dissection, cases with R 0 resection, cases with R 1 resection in the neoadjuvant chemotherapy group and the adjuvant chemotherapy group were 1, 22, 23, 0 and 0, 23, 23, 0, respectively, showing no significant difference in the above indicators between the two groups ( P>0.05). The number of lymph node dissected, the volume of intraoperative blood loss, duration of postoperative hospital stay in the neoadjuvant chemotherapy group and the adjuvant chemotherapy group were 28(range, 22-37), 150 (range, 100-200)mL, 11(range, 8-16)days and 25(range, 18-32), 150(range, 100-200)mL, 11(range, 9-18)days, respec-tively, showing no significant difference in the above indicators between the two groups ( Z=-1.13, -0.32, -0.50, P>0.05). Cases with complications ≥grade Ⅱ of Clavien-Dindo classification during the postoperative 30 days were 2 in the neoadjuvant chemotherapy group, including 1 case of abdominal abscess and 1 case of pneumonia. Cases with complications ≥grade Ⅱ of Clavien-Dindo classification during the postoperative 30 days were 8 in the adjuvant chemotherapy group, including 3 cases of abdominal abscess, 2 cases of anastomotic fistula, 1 case of pneumonia, 1 case of pancreatic fistula, 1 case of gastric emptying disability. There were significant differences in the complications ≥grade Ⅱ of Clavien-Dindo classification between the neoadjuvant chemotherapy group and the adjuvant chemotherapy group ( χ2=4.60, P<0.05). There was no significant difference in the abdominal abscess, anastomotic fistula, pneumonia, pancreatic fistula, gastric emptying disability between the two groups ( P>0.05). None of patient died in either of the neoadjuvant chemotherapy group and the adjuvant chemotherapy group. (3) Prognosis. Of 46 patients, 43 cases were followed up for 15.4(range, 3.0-84.0)months. The overall survival time of patients in the neoadjuvant chemotherapy group and the adjuvant chemotherapy group were (14±10)months and (24±22)months, showing no significant difference between them ( hazard ratio=0.82, 95% confidence interval as 0.28-2.40, P>0.05). Conclusion:Compared with postoperative adjuvant chemotherapy, neoadjuvant chemotherapy does not increase the surgical risk of locally advanced gastric cancer patients undergoing multivisceral and radical resection, and can reduce the incidence of complications ≥grade Ⅱ of Clavien-Dindo classification during the postoperative 30 days, but does not improve patient survival.

Objective: To investigate the differences of clinicopathological features, diagnosis, treatment and prognosis between patients with extra-gastrointestinal stromal tumors (EGIST) and duodenal gastrointestinal stromal tumors (DGIST). Methods: A retrospective case - control study was performed. Case inclusion criteria: (1) tumor confirmed by histology and pathology; (2) primary tumor locating in the extra - gastrointestinal tract or duodenum; (3) without other synchronous tumors; (4) complete clinical and pathological data. Clinical data of 20 EGIST patients and 32 DGIST patients from March 2011 to September 2016 at Department of Gastrointestinal Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine were retrospectively collected and analyzed. The observational parameters included clinicopathological characteristics, treatment and prognosis conditions. Continuous data of abnormal distribution were expressed as median (range) and compared using the Mann-Whitney U-test. Survival curves were drawn by the Kaplan-Meier method and compared with the Log-rank test. Results: Of the 20 EGIST patients, 8 were males and 12 were females with age of 61.0 (30.0 to 86.0) years and of the 32 DGIST patients, 12 were males and 20 were females with age of 55.5 (27.0 to 70.0) years. Compared with DGIST patients, EGIST patients were older (U=188.000, P=0.012], had larger tumor size [10.0 (3.0 to 29.0) cm vs. 4.0 (1.5 to 10.0) cm, U=98.500, P<0.001] and higher ratio of high risk classification [85.0% (17/20) vs. 12.5% (4/32), χ²=26.870, P<0.001]. Among the 20 EGIST patients, 5 were diagnosed with distal metastasis and received imatinib (400 mg/d), and the other 15 patients underwent radical resection who were included in survival analysis. All the 32 DGIST patients underwent radical resection. The median follow-up of whole group was 43 (14 to 76) months. The 3-year recurrence/metastasis-free survival rate of 15 cases undergoing radical resection in the EGIST group was 85.6%, which was lower than that of the DGIST group (88.6%), and the difference was not statistically significant (P=0.745). There was no significant difference in the 3-year overall survival rate between the EGIST group (92.9%) and the DGIST group (100%) (P=0.271). Conclusions As compared to DGIST, EGIST mostly occurs in those with older age, larger tumor size and higher risk grade. The prognosis of EGIST patients after radical resection is similar to that of DGIST patients.

Objective To investigate the differences of clinicopathological features, diagnosis, treatment and prognosis between patients with extra?gastrointestinal stromal tumors (EGIST) and duodenal gastrointestinal stromal tumors (DGIST). Methods A retrospective case?control study was performed. Case inclusion criteria: (1) tumor confirmed by histology and pathology; (2) primary tumor locating in the extra?gastrointestinal tract or duodenum; (3) without other synchronous tumors; (4) complete clinical and pathological data. Clinical data of 20 EGIST patients and 32 DGIST patients from March 2011 to September 2016 at Department of Gastrointestinal Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine were retrospectively collected and analyzed. The observational parameters included clinicopathological characteristics, treatment and prognosis conditions. Continuous data of abnormal distribution were expressed as median (range) and compared using the Mann?Whitney U?test. Survival curves were drawn by the Kaplan?Meier method and compared with the Log?rank test. Results Of the 20 EGIST patients, 8 were males and 12 were females with age of 61.0 (30.0 to 86.0) years and of the 32 DGIST patients, 12 were males and 20 were females with age of 55.5 (27.0 to 70.0) years. Compared with DGIST patients, EGIST patients were older (U=188.000, P=0.012], had larger tumor size [10.0 (3.0 to 29.0) cm vs. 4.0 (1.5 to 10.0) cm, U=98.500, P<0.001] and higher ratio of high risk classification [85.0% (17/20) vs. 12.5% (4/32), χ2=26.870, P<0.001]. Among the 20 EGIST patients, 5 were diagnosed with distal metastasis and received imatinib (400 mg/d), and the other 15 patients underwent radical resection who were included in survival analysis. All the 32 DGIST patients underwent radical resection. The median follow?up of whole group was 43 (14 to 76) months. The 3?year recurrence/metastasis?free survival rate of 15 cases undergoing radical resection in the EGIST group was 85.6%, which was lower than that of the DGIST group (88.6%), and the difference was not statistically significant (P=0.745). There was no significant difference in the 3?year overall survival rate between the EGIST group (92.9%) and the DGIST group (100%) (P=0.271). Conclusions As compared to DGIST, EGIST mostly occurs in those with older age, larger tumor size and higher risk grade. The prognosis of EGIST patients after radical resection is similar to that of DGIST patients.

Objective To investigate the differences of clinicopathological features, diagnosis, treatment and prognosis between patients with extra?gastrointestinal stromal tumors (EGIST) and duodenal gastrointestinal stromal tumors (DGIST). Methods A retrospective case?control study was performed. Case inclusion criteria: (1) tumor confirmed by histology and pathology; (2) primary tumor locating in the extra?gastrointestinal tract or duodenum; (3) without other synchronous tumors; (4) complete clinical and pathological data. Clinical data of 20 EGIST patients and 32 DGIST patients from March 2011 to September 2016 at Department of Gastrointestinal Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine were retrospectively collected and analyzed. The observational parameters included clinicopathological characteristics, treatment and prognosis conditions. Continuous data of abnormal distribution were expressed as median (range) and compared using the Mann?Whitney U?test. Survival curves were drawn by the Kaplan?Meier method and compared with the Log?rank test. Results Of the 20 EGIST patients, 8 were males and 12 were females with age of 61.0 (30.0 to 86.0) years and of the 32 DGIST patients, 12 were males and 20 were females with age of 55.5 (27.0 to 70.0) years. Compared with DGIST patients, EGIST patients were older (U=188.000, P=0.012], had larger tumor size [10.0 (3.0 to 29.0) cm vs. 4.0 (1.5 to 10.0) cm, U=98.500, P<0.001] and higher ratio of high risk classification [85.0% (17/20) vs. 12.5% (4/32), χ2=26.870, P<0.001]. Among the 20 EGIST patients, 5 were diagnosed with distal metastasis and received imatinib (400 mg/d), and the other 15 patients underwent radical resection who were included in survival analysis. All the 32 DGIST patients underwent radical resection. The median follow?up of whole group was 43 (14 to 76) months. The 3?year recurrence/metastasis?free survival rate of 15 cases undergoing radical resection in the EGIST group was 85.6%, which was lower than that of the DGIST group (88.6%), and the difference was not statistically significant (P=0.745). There was no significant difference in the 3?year overall survival rate between the EGIST group (92.9%) and the DGIST group (100%) (P=0.271). Conclusions As compared to DGIST, EGIST mostly occurs in those with older age, larger tumor size and higher risk grade. The prognosis of EGIST patients after radical resection is similar to that of DGIST patients.