The incidence and locational predilection of metachronous tumors after endoscopic resection of high-grade dysplasia and early gastric cancer.

Background: The incidence of metachronous lesions after endoscopic resection (ER) of high-grade dysplasia (HGD) has not been evaluated, and optimal surveillance strategy remains vague. This study aimed to evaluate the incidence and characteristics of metachronous tumors including HGD and early gastric cancer (EGC) arising after ER.
Patients: The medical records of 2779 patients with 2981 lesions (445 patients with HGD and 2334 patients with EGC) who underwent ER and surveillance endoscopy at Asan Medical Center between April 1999 and December 2011 were retrospectively reviewed, and clinicopathological features of metachronous tumors were analyzed.
Results: Ninety-six metachronous lesions (17 HGD and 79 EGC) occurred in 92 patients during median 42 months of follow-up period (range 26-58 months). The 5-year and 10-year overall cumulative incidences of metachronous tumors were 4.6 and 10.5 %, respectively, and were on steady rise up to 10 years. The 5- and 10-year cumulative incidences of metachronous lesions were 4.1 and 8.4 % in HGD group and 4.7 and 11.3 % in EGC group (P = 0.578), respectively. The size of metachronous tumors was significantly smaller than initial lesion (2.3 vs. 1.9 cm, P = 0.039). Lower third of the stomach was most frequent site for both initial and metachronous lesions (77.1 and 70.8 %, respectively) and age was the significant predicting factor for metachronous tumors.
Conclusions: Cumulative incidence of metachronous tumors after ER of HGD was comparable to the incidence after ER of EGC. Surveillance endoscopy can be considered at least for 10 years, with special attention on the lower third of the stomach.