Endoscopic Diagnosis of the Invasion Depth of T1 Colorectal Carcinoma for Endoscopic Resection by Using Narrow-Band Imaging Magnification as Total Excisional Biopsy.

ABSTRACT

BACKGROUND/AIMS: We established a new colorectal T1 invasion depth sub-classification and evaluated it to determine whether total excisional biopsy can be performed on colorectal carcinoma (CRC) cases using narrow-band imaging (NBI) magnification. METHODS: The cases included 73 T1 carcinomas selected from 173 early CRC cases. The T1 invasion depth sub-classification was defined as follows T1a, invasion less than 1,000 µm from the inferior border of the muscularis mucosae; T1b-1, between T1a and T1b-2; and T1b-2, T1b lesions with invasion from the deepest part of the carcinoma to within 1,000 µm of the superior border of the muscularis propria. The T1b-2 lesions were not suitable for total excisional biopsy to be performed on them. We examined the maximum diameter of Type C2 (NBI Hiroshima classification) areas and invasion depth. RESULTS: Among 47 lesions classified as Type C2, 38 lesions showed a maximum diameter of 10 mm or less and were classified as Tis, T1a, or T1b-1. The remaining 9 lesions exceeded 10 mm, and among these, 3 cases were classified as T1b-2 (p = 0.0035). CONCLUSION: For using the new T1 invasion depth sub-classification to classify T1 CRCs in which total excisional biopsy is possible, it is useful to measure the maximum diameter of the Type C2 area.