[Pit pattern and endoscopic mucosal resection in diagnosis and treatment of colorectal tumors].

Objective: To explore the effective methods to diagnose and treat colorectal cancer in its early stage.

Methods: 1 205 patients were examined by colonoscopy and mucosa staining with indigocarmine. The pit patterns were observed with magnifying endoscope and stereomicroscope according to the Kudo classification. The pathological diagnoses of the lesions were compared with their pit patterns. Electrocoagulation resection was performed on the prominent lesions and endoscopic mucosal resection (EMR) or endoscopic partial mucosal resection (EPMR) was performed on the flat lesions.

Results: In the 282 patients 478 prominent and flat lesions were found. There were 16 cases of laterally spreading tumor (LST), including I case of pit pattern II, 6 of pit pattern IIIL, 8 of pit pattern IV, and 1 of pit pattern Va, with 2 cases of intramembrane cancer and 1 case of IIa + IIc lesions invading the superficial myometrium among them. EMR and EPMR were performed on 14 LST lesions, 22 IIa lesions, and 14 IIb lesions.

Conclusion: The examination of pit pattern is very important in early diagnosis of colorectal cancer and differentiation tumorous from non-tumorous lesions. V type pit pattern is an indicator of colorectal cancer. EMR and EPMR are safe and effective for flat lesions.