Objective To investigate the clinical efficacy and prognostic factors of neoadju-vant chemotherapy (NACT) and radical resection on adenocarcinoma of esophagogastric junction (AEG) and gastric adenocarcinoma (GC).

Methods The propensity score matching and retrospec-tive cohort study was conducted. The clinicopathological data of 263 patients with AEG and GC who were admitted to Peking University Cancer Hospital from March 2017 to March 2022 were collected. There were 204 males and 59 females, aged (60±10)years. Of the 263 patients, 81 cases with AEG were set as the AEG group, and 182 cases with GC were set as the GC group. Observation indicators: (1) propensity score matching and comparison of clinicopathological characteristics of patients between the two groups after matching; (2) evaluation of the efficacy of NACT and pathological conditions; (3) intraoperative and postoperative conditions; (4) follow-up; (5) analysis of factors affecting prognosis of patients. Comparison of measurement data with normal distribution between groups was conducted using the independent sample t test. Comparison of measurement data with skewed distribution between groups was conducted using the Mann-Whitney rank sum test. Comparison of count data between groups was conducted using the chi-square test. Comparison of ordinal data between groups was conducted using the nonparametric rank sum test. The Cox proportional hazard model was used for univariate and multivariate analyses. The Kaplan-Meier method was used to calculate survival rate and draw survival curve. The Log-rank test was used for survival analysis. Propensity score matching was done by the 1:1 nearest neighbor matching method with a caliper value of 0.02.

Results (1) Propensity score matching and comparison of clinicopathological charac-teristics of patients between the two groups after matching. Of 263 patients, 156 cases were succe-ssfully matched, including 78 cases in the AEG group and 78 cases in the GC group. After propensity score matching, the elimination of age and degree of tumor differentiation confounding bias ensured comparability between the two groups. (2) Evaluation of the efficacy of NACT and pathological condi-tions. After propensity score matching, cases with patholo-gical complete response were 2 in the AEG group, versus 9 in the GC group, showing a significant difference between the two groups (χ²=4.793, P < 0.05). (3) Intraoperative and postoperative condi-tions. After propensity score matching, the operation time of AEG group was 225(200, 283)minutes. The resection range (whole stomach, distal stomach, proximal stomach) were 68, 0, 10, respectively. The digestive tract reconstruction methods (Roux-en-Y, Billroth Ⅰ/Ⅱ/Uncut Roux-en-Y, esophageal residual gastric, double channel) were 68, 0, 5, 5, respectively. Duration of postoperative hospital stay was 12(10, 16)days. Total hospi-talization expense was (114 400±4 828)yuan. The above indicators of the GC group were 200(174, 234)minutes, 22, 55, 1, 21, 56, 0, 1, 10(9, 11)days, (98 790±2 549)yuan, respectively. There were significant differences in the above indicators between the two groups (Z=-3.813, χ²=85.875, 88.487, Z=-4.060, t=2.524, P < 0.05). Cases of complication and cases of serious complication were 32 and 9 in the AEG group, versus 22 and 5 in the GC group, showing no significant difference between the two groups (χ²=2.832, 1.256, P > 0.05). (4) Follow-up. All 156 pati-ents after propensity score matching were followed up after surgery, with a follow-up time of 51(range, 3-84)months. Number of death in the AEG group and GC group were 26 and 25 during the follow-up. The postoperative 3-, 5-year overall survival rate were 70.4%, 58.3% in patients of the AEG group, versus 75.7%, 62.6% in patients of the GC group, showing no significant difference in overall survival between the two groups (χ²=0.141, P > 0.05). (5) Analysis of factors affecting prognosis of patients. Results of multivariate analysis showed that NACT, average tumor diameter after NACT, vascular tumor emboli were independent factors affecting prognosis of patients with AEG and GC after NACT and radical resection before propensity score matching (hazard ratio=1.864, 1.807, 4.551, 95% confidence interval as 1.137-3.056, 1.124-2.903, 2.709-7.645, P < 0.05).

Conclusions Compared with patients of GC, patients of AEG have a lower proportion of pathological complete response after NACT, but there is no signifi-cant difference in the incidence of complication and survival of patients with AEG and GC after NACT and radical resection. NACT, average tumor diameter after NACT, vascular tumor emboli are indepen-dent factors affecting prognosis of patients with AEG and GC after NACT and radical resection.