Clinicopathologic Similarities of the Main and Minor Lesions of Synchronous Multiple Early Gastric Cancer

The detection rate of early gastric cancer (EGC) is increasing due to improvements in diagnostic methods, but synchronous multiple EGC (SMEGC) remains a major problem. Therefore, we investigated the characteristics of and the correlation between the main and minor lesions of SMEGC. We retrospectively reviewed the medical records of patients with EGC between April 2008 and May 2013. The main lesion was defined as the one with the greatest invasion depth. If lesions had the same invasion depth, the tumor diameter was used to define the main lesion. Of 963 patients who had treatment for EGC, 37 patients with SMEGC were analyzed. The main and minor lesions showed a significant positive correlation of size (r = 0.533, P = 0.001). The main and minor lesions of SMEGC showed the same vertical and horizontal locations at 70.3% and 64.9%, respectively (P = 0.002 and P = 0.002). Macroscopic types were identical in 67.6% (P < 0.001), and 32.4% had identical macroscopic type and location. The main and minor lesions had identical characteristics of invasion depth, presence of lymphovascular invasion (LVI), and differentiation in 78.4%, 83.8%, and 83.8%, respectively. Differentiation, LVI, and invasion depth (microscopic characteristics) were simultaneously the same in 62.2%. The location, macroscopic type, and 3 microscopic characteristics were matched in 27%. The main and minor lesions of SMEGC have similar clinicopathologic characteristics. Therefore, the possibility of SMEGC should not be neglected in cases of EGC, considering an understanding of the characteristics and association of lesions.