ObjectiveTo study the different clinical features of early gastric cardia carcinoma (EGCC) patients with synchronous tumor, and identify the risk factors and prognosis of the occurence of synchronous tumor after endoscopic resection. MethodsA retrospective study was made on the data of 499 patients (512 lesions) who underwent cardiac endoscopic submucosal dissection (ESD) and were pathologically confirmed as EGCC in Nanjing Drum Tower Hospital from January 2011 to June 2018. The patients were divided into synchronous tumor group (47 patients with 50 lesions) and non-synchronous tumor group (452 patients with 462 lesions). Univariate and multivariate logistic regression analysis were performed to identify independent risk factors for the occurrence of synchronous tumor. Kaplan-Meier method was conducted to prognosis. Differences between the two groups were analyzed for significance by the log-rank test. ResultsAmong the 499 patients, the incidence of synchronous tumor was 9.4% (47/499). Logistic regression analysis showed that the lesion size (P=0.046, OR=0.807, 95%CI: 0.653-0.996), atrophic gastritis and intestinal metaplasia (P=0.017, OR=3.207, 95%CI: 1.229-8.371), Helicobacter pylori infection (P=0.046, OR=1.952, 95%CI: 1.013-3.761) were independent risk factors for the occurrence of synchronous tumor after endoscopic resection. A total of 453 （90.8%）patients were successfully followed up. Kaplan-Meier curve showed that the overall survival rate of the synchronous tumor group and the non-synchronous tumor group were 95.2% and 97.6%, respectively (P=0.72). ConclusionThe incidence of EGCC accompanied with synchronous tumor is not high, but it should not be neglected. For patients with small lesions, it is necessary to consider the possibility of main cancer in other parts. For patients with Helicobacter pylori infection or severe mucosal atrophy and intestinal metaplasia, more attention should be paid to the mucosa around the lesion during endoscopic examination and strict endoscopic follow-up should be carried out.