AIM: To determine the effective hospitalization period as the clinical pathway to prepare patients for endoscopic submucosal dissection (ESD). METHODS: This is a retrospective observational study which included 189 patients consecutively treated by ESD at the National Cancer Center Hospital from May 2007 to March 2009. Patients were divided into 2 groups; patients in group A were discharged in 5 d and patients in group B included those who stayed longer than 5 d. The following data were collected for both groups: mean hospitalization period, tumor site, median tumor size, post-ESD rectal bleeding requiring urgent endoscopy, perforation during or after ESD, abdominal pain, fever above 38 ℃, and blood test results positive for inflammatory markers before and after ESD. Each parameter was compared after data collection. RESULTS: A total of 83% (156/189) of all patients could be discharged from the hospital on day 3 postESD. Complications were observed in 12.1% (23/189) of patients. Perforation occurred in 3.7% (7/189) of patients. All the perforations occurred during the ESD procedure and they were managed with endoscopic clipping. The incidence of post-operative bleeding was 2.6% (5/189); all the cases involved rectal bleeding. We divided the subjects into 2 groups: tumor diameter ≥ 4 cm and < 4 cm; there was no significant difference between the 2 groups (P = 0.93, χ 2 test with Yates correction). The incidence of abdominal pain was 3.7% (7/189). All the cases occurred on the day of the procedure or the next day. The median white blood cell count was 6800 ± 2280 (cells/μL; ± SD) for group A, and 7700 ± 2775 (cells/μL; ± SD) for group B, showing a statistically significant difference (P = 0.023, t-test). The mean C-reactive protein values the day after ESD were 0.4 ± 1.3 mg/dL and 0.5 ± 1.3 mg/dL for groups A and B, respectively, with no significant difference between the 2 groups (P = 0.54, t -test). CONCLUSION: One-day admission is sufficient in the absence of complications during ESD or early postoperative bleeding. AIM: To determine the effective hospitalization period as the clinical pathway to prepare patients for endoscopic submucosal dissection (ESD). METHODS: This is a retrospective observational study which included 189 patients consecutively treated by ESD at the National Cancer Center Hospital from May 2007 to March 2009. Patients were segment into 2 groups; patients in group A were discharged in 5 d and patients in group B included those who stayed longer than 5 d. The following data were collected for both groups: mean hospitalization period, tumor site, median tumor Size, post-ESD rectal syndrome when urgent endoscopy, perforation during or after ESD, abdominal pain, fever above 38 °C, and blood test results positive for inflammatory markers before and after ESD. Each parameter was compared after data collection. RESULTS: A total Of 83% (156/189) of all patients could be discharged from the hospital on day 3 postESD. Complications were observed in 12.1% (23/189) of patients. Perf Oration occurred in 3.7% (7/189) of patients. All the perforations occurred during the ESD procedure and they were managed with endoscopic clipping. The incidence of post-operative was was 2.6% (5/189); all the cases involved rectal We found the subjects into 2 groups: tumor diameter ≥ 4 cm and < 4 cm; there was no significant difference between the two groups (P = 0.93, χ 2 test with Yates correction). The incidence of abdominal pain was 3.7%. (7/189). All the cases occurred on the day of the procedure or the next day. The median white blood cell count was 6800 ± 2280 (cells/μL; ± SD) for group A, and 7700 ± 2775 (cells/ μL; ± SD) for group B, showing a robust ly significant difference (P = 0.023, t-test). The mean C-reactive protein values ​​the day after ESD were 0.4 ± 1.3 mg/dL and 0.5 ± 1.3 mg/dL for The difference between groups A and B, respectively, with no significant difference between the two groups (P = 0.54, t -test). CONCLUSION: One-day admission is sufficient in the abs Ence of complIndication during ESD or early postoperative injury.