Objective   To assess the value of endoscopic submucosal dissection (ESD) for flat colorectal precancer or cancer in-situ lesions.   Methods   ESD was performed in 35 patients [male: 21

60%; age: 23-87 (62±12) years old] with flat colorectal precancer or cancer in-situ lesions from Nov

2006 to Feb

2009. Complications and relapse rate were analyzed.   Results   There were 21 cases of precancer and 14 cases of cancer in-situ lesions. In these patients

lower rectal lesions (lower than 7 cm from anal) were found in 14 cases

upper rectal lesions in 7 cases

lesions of the sigmoid colon in 4 cases

lesions of the liver flex in 5 cases

and lesions of the cecum and ascending colon in 5 cases

respectively. All the patients underwent ESD successfully. The median operative time was 38 (15-114) min and median blood loss was 32 (5-400) ml. Mean diameter of the lesions was [2.0-8.5 (2.4±2.3)] cm. The main complications included perforation in 3 cases

intraoperative bleeding in 7 cases

and delayed bleeding in 3 cases. A follow-up for 3-23 (11±5) months found no recurrence in all cases.   Conclusion   ESD is an effective

safe

minimal invasive method for the treatment of flat colorectal precancer or cancer in-situ lesions.