Long-term outcomes of endoscopic submucosal dissection in comparison to surgery in undifferentiated-type intramucosal gastric cancer using propensity score analysis

Jun Chul Park, Yong Kang Lee, Soon Young Kim, Yunho Roh, Kyu Yeon Hahn, Sung Kwan Shin, Sang Kil Lee, Yong Chan Lee, Hyoung-Il Kim, Jae-Ho Cheong, Woo Jin Hyung, Sung Hoon Noh

The treatment of intramucosal early gastric cancer with undifferentiated-type histologies (UD-EGCs) using endoscopic submucosal dissection (ESD) is controversial. This study aimed to compare the clinical and oncologic long-term outcomes of ESD and surgery for UD-EGCs. A prospectively collected database of patients who underwent ESD or surgery between January 2006 and December 2012 was established. Patients who diagnosed with UD-EGC and satisfied the expanded indications of ESD were included. Clinical data from 111 patients treated with ESD and 382 patients underwent surgery were analyzed, and 1-1 propensity score-matched 81 pairs of patients were also compared. In both groups, two-thirds of the UD-EGCs had signet ring cell (SRC)-type histology and about 90% of UD-EGCs were flat or depressed types. The mean size of tumors was smaller in ESD group (9.7 vs. 13.2 mm; P < 0.001). After propensity score-matched, case-matching covariates were not significantly different between the groups. Disease-free survival (DFS) was significantly shorter in the ESD group, but overall survival (OS) was not different between the two groups both in overall comparison (DFS; P < 0.001 and OS; P = 0.078) and propensity score-matched analysis (DFS; P < 0.001 and OS; P = 0.850). According to histologic type, OS of SRC histology was not different between the group, both in overall comparison and propensity score-matched analysis (P = 0.286 and P = 0.210). On the other hands, OS of poorly differentiated adenocarcinoma was significantly shorter in ESD group in overall comparison (P = 0.007), but was not as so in propensity score-matched analysis (P = 0.088). ESD might be a complementary option for the treatment of UD-EGCs, especially in those with SRC-type histology based on strict expanded indications. Nonetheless, close endoscopic surveillance is required because of a high incidence of intragastric recurrence.