The frequency of early colorectal cancer derived from sessile serrated adenoma/polyps among 1858 serrated polyps from a single institution.
OBJECTIVE
Sessile serrated adenoma/polyps (SSAPs) are suspected to have a high malignant potential, although few reports have evaluated the incidence of carcinomas derived from SSAPs using the new classification for serrated polyps (SPs). The aim of study was to compare the frequency of cancer coexisting with the various SP subtypes including mixed polyps (MIXs) and conventional adenomas (CADs).


METHODS
A total of 18,667 CADs were identified between April 2005 and December 2011, and 1858 SPs (re-classified as SSAP, hyperplastic polyp (HP), traditional serrated adenoma (TSA), or MIX) were removed via snare polypectomy, endoscopic mucosal resection, or endoscopic sub-mucosal dissection.


RESULTS
Among 1160 HP lesions, 1 (0.1%) coexisting sub-mucosal invasive carcinoma (T1) was detected. Among 430 SSAP lesions, 3 (0.7%) high-grade dysplasia (HGD/Tis) and 1 (0.2%) T1 were detected. All of the lesions were detected in the proximal colon, with a mean tumor diameter of 18 mm (SD 9 mm). Among 212 TSA lesions, 3 (1%) HGD/Tis were detected but no T1 cancer. Among 56 MIX lesions, 9 (16%) HGD/Tis and 1 (2%) T1 cancers were detected, and among 18,677 CAD lesions, 964 (5%) HGD/Tis and 166 (1%) T1 cancers were identified.


CONCLUSIONS
Among the resected lesions that were detected during endoscopic examination, a smaller proportion (1%) of SSAPs harbored HGD or coexisting cancer, compared to CAD or MIX lesions. Therefore, more attention should be paid to accurately identifying lesions endoscopically for intentional resection and the surveillance of each SP subtype.
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan. akiko.chino@jfcr.or.jp.
A
A
Chino
Division of Pathology, The Cancer Institute of Japanese Foundation of Cancer Research, Tokyo, Japan.
N
N
Yamamoto
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.|Division of Pathology, The Cancer Institute of Japanese Foundation of Cancer Research, Tokyo, Japan.
Y
Y
Kato
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.
K
K
Morishige
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.
H
H
Ishikawa
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.|Division of Pathology, The Cancer Institute of Japanese Foundation of Cancer Research, Tokyo, Japan.
T
T
Kishihara
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.
J
J
Fujisaki
Division of Pathology, The Cancer Institute of Japanese Foundation of Cancer Research, Tokyo, Japan.
Y
Y
Ishikawa
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.
Y
Y
Tamegai
Department Digestive Endoscopy, The Cancer Institution Hospital, Japanese Foundation of Cancer Research, Tokyo, Japan.
M
M
Igarashi
D000236:Adenoma / Q000145:classification / Q000473:pathology*; D003110:Colonic Neoplasms / Q000145:classification / Q000473:pathology*; D003111:Colonic Polyps / Q000145:classification / Q000473:pathology*; D003113:Colonoscopy; D006801:Humans; D006965:Hyperplasia; D008297:Male; D008875:Middle Aged
Cancer derived from sessile serrated adenoma/polyp; Hyperplastic polyp; Mixed serrated polyp; Serrated polyp pathway; Sessile serrated adenoma/polyp