The Clinical Impact of Synchronous and Metachronous Other Primary Cancer in Gastric Cancer Patients Who Receive Curative Treatment.

BACKGROUND/AIM: The present study evaluated the clinical characteristics and prognostic factors of gastric cancer (GC) patients with synchronous and metachronous other primary cancer who received curative treatment for GC. PATIENTS AND METHODS: The study included 244 patients who underwent curative treatment for GC between 2005 and 2018. The risk factors for the overall survival (OS) and recurrence-free survival (RFS) were identified. RESULTS: A total of 244 patients were included in this study. Among them, 58 patients were diagnosed with synchronous and metachronous other primary cancer. When comparing the patient background characteristics and clinical course between GC patients without and with synchronous and metachronous other primary cancer, the background, postoperative surgical complications, and details of adjuvant treatment were similar between the two groups. The 3- and 5-year OS rates in GC patients with synchronous and metachronous other primary cancer were 69.7% and 48.0%, respectively, while those in patients without synchronous and metachronous other primary cancer were 80.6% and 74.3%, respectively, showing a statistically significant difference (p<0.001) The synchronous and metachronous other primary cancer status was included in the final multivariate analysis model (hazard ratio=2.201; 95% confidence interval=1.229-3.942; p=0.008). CONCLUSION: Synchronous and metachronous other primary cancer status is a prognostic factor in GC patients. Therefore, synchronous and metachronous other primary cancer patients need both other primary cancer and GC follow-up to improve their survival.