Comparison of clinicopathological features and long-term prognosis between mixed predominantly differentiated-type and pure differentiated-type early gastric cancer.

BACKGROUND: Recent studies have shown that mixed predominantly differentiated-type (MD) early gastric cancer (EGC) might have more malignant potential than pure differentiated-type (PD) EGC. However, no study has analyzed all differentiated-type EGC cases treated endoscopically and surgically. This study aimed to compare the differences in clinicopathological features and long-term prognosis between MD- and PD-EGC. METHODS: We evaluated all patients with differentiated-type EGCs who were treated endoscopically and surgically in our hospital between January 2010 and October 2014. The clinicopathological features and long-term prognosis of MD-EGC were compared with those of PD-EGC. RESULTS: A total of 459 patients with 459 lesions were evaluated in this study; of them, 409 (89.1%) and 50 (10.9%) were classified into the PD and MD groups, respectively. Submucosal invasion was found in 96 (23.5%) patients of the PD group and in 33 (66.0%) patients of the MD group (p < 0.01). The rates of positive lymphatic and vascular invasion and ulceration were significantly higher in the MD group than in the PD group (p < 0.01). The proportion of patients with lymph node metastasis was also significantly higher in the MD group than in the PD group (5 (10%) vs 6 (1.5%), p < 0.01). The 5-year overall and EGC-specific survival rates in the PD group were 88.3 and 99.5%, respectively, while they were 94.0 and 98.0% in the MD group, respectively. CONCLUSIONS: MD-EGC has more malignant potential than PD-EGC. However, the long-term prognosis of MD-EGC is good and is not significantly different from that of PD-EGC when treated appropriately.

Association of second surveillance colonoscopy findings with index and first surveillance colonoscopy results.

OBJECTIVE: Although there have been established guidelines for first surveillance colonoscopy (FSC) after a polypectomy, there is no consensus on performing a second surveillance colonoscopy (SSC), especially in Asian countries. This study aimed to investigate the association of SSC findings with index total colonoscopy (TCS) and FSC results. METHODS: This was a single-center retrospective cohort study involving 1928 consecutive Japanese patients who had received three or more colonoscopies. High-risk colonoscopic findings were defined as advanced adenoma (≥10 mm in size, with a villous histology or high-grade dysplasia) or more than three adenomas, whereas low-risk findings were defined as one to two non-advanced adenomas. On the basis of index TCS results, the patients were divided into three groups: no adenomas (NA) (n = 888), low-risk (LR) (n = 476), and high-risk (HR) (n = 564) groups, respectively. RESULTS: In the NA group, the rate of high-risk findings on SSC was significantly higher in patients with high-risk or low-risk findings on FSC than in those with no adenoma (7.7% and 7.9% vs 2.2%, P < 0.05). Patients in the LR and HR groups with high-risk findings on FSC had a significantly higher risk on SSC than those with low-risk findings or no adenoma on FSC (LR group: 28.6%, 9.4%, and 5.9%, respectively, P < 0.01; HR group: 34.5%, 18.8%, and 7.9%, respectively, P < 0.01). CONCLUSIONS: Index TCS and especially FSC findings were predictive of SSC results. The study results may be useful for determining appropriate intervals for surveillance colonoscopy in Asian countries.