Depressed Lesions Are Different at a Histologic and Molecular Level
Douglas K. Rex, MD, MASGE, reviewing Kudo S, et al. Clin Transl Gastroenterol 2020 Dec.
In a study from Japan, T1 colorectal cancers and adenomas were classified as “depressed,” “flat,” or “protruded” subtypes. Depressed lesions constituted only 1.2% of all neoplasms, but 66% of the depressed lesions were cancerous compared to 2.6% each with the other two lesion subtypes. Compared to nondepressed carcinomas, depressed T1 cancers were less likely to have residual adenoma, more likely to have deep submucosal or lymphovascular invasion, and more likely to have a recurrence or distant metastasis. Depressed adenomas were considerably more likely than flat or protruded adenomas to have high-grade dysplasia.
Depressed adenomas, however, were much less likely than nondepressed adenomas to express KRAS mutations.
Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.
Kudo S, Kouyama Y, Ogawa Y, et al. Depressed colorectal cancer: a new paradigm in early colorectal cancer. Clin Transl Gastroenterol 2020;11:e00269. (https://dx.doi.org/10.14309%2Fctg.0000000000000269)