The Clinicopathologic Features of Synchronous and Metachronous Cancer in Patients with Gastric Cancer

Purpose: With the development of diagnostic techniques, second primary neoplasms such as synchronous or metachronous cancers in gastric cancer patients are being increasingly found. In this study, we investigated the clinicopathological features and clinical significance of gastric neoplasms combined with synchronous and metachronous cancers. Materials and Methods: 1,048 patients who were diagnosed with gastric cancer in Chosun University Hospital from January 1998 to March 2008 were retrospectively reviewed. Results: 38 of the 1,048 patients with gastric cancer (3.6%) had synchronous and metachronous cancers. Of the 38 patients, 16 patients (42.1%) had synchronous cancer and 22 patients (57.9%) had metachronous cancer. The average time interval between gastric cancer and the secondary primary cancer was months. The most common second primary neoplasm was lung cancer (8/38, 21.1%), followed by colorectal cancer (8/38, 21.1%). Among the 27 patients who underwent surgical resection for gastric cancer, 5 patients (18.5%) were in the synchronous group and 22 patients (81.5%) were in the metachronous group. The mean survival time of the 38 patients was 49.8 months. The mean survival time was 24.6 months for the synchronous cancer patients and 68.1 month for the metachronous cancer patients. The 3 year survival rate of the synchronous group and the metachronous group was 33.3% and 81.1%, respectively. Conclusion: We must pay attention on the preoperative workup for synchronous cancer and on the postoperative follow-up for metachronous cancer in gastric cancer patients.