The Clinical Significance of the Absolute and Relative Classification of the Depth of Invasion for Submucosal Invasive Carcinomas of the Colon

Lee, Soo Jung; Kim, Jin Oh; Eun, Soo Hoon; Joo, Hyun Soo; Kim, Yeon Soo; Jung, Hyun Ku; Jung, In Seop; Ko, Bong Min; Cho, Joo Young; Lee, Joon Seong; Lee, Moon Sung; Jin, So Young; Shim, Chan Sup; Kim, Boo Sung

Abstract

BACKGROUND/AIMS: We investigated the clinical significance of the criteria of the absolute and relative depth of invasion for submucosal invasive colorectal carcinomas.
METHODS
We analyzed retrospectively the clinicopathological features of 29 submucosal invasive colorectal cancers. The relative depth of submucosal invasion was evaluated by a relative (sm1, 2, 3) classification and the absolute depth of submucosal invasion was measured in micrometers from the lower border of the muscularis mucosa to the deepest cancer gland.
RESULTS
All sm1 cancers showed a submucosal layer invasion of less than 1,000micronm; invasion was seen between 500micronm and 1,000micronm. The rate of lymphovascular invasion was higher for sm1c, sm2 and sm3 than for sm1a and sm1b, and the rate of invasion was higher for a level of 500micronm or more than for a level of 500micronm or less for the depth of submucosal invasion. One of sixteen patients that underwent surgery showed lymph node involvement. For this patient, the relative depth of invasion was sm1c and the absolute depth was 900micronm.
CONCLUSIONS
Endoscopically treated submucosal colorectal cancer needs to be evaluated by the absolute depth in addition to the relative depth. It seems that a submucosal invasive cancer less than 500micronm in submucosal depth probably can be treated by endoscopic resection.