CC BY-NC-ND 4.0 · Endosc Int Open 2018; 06(02): E156-E164
DOI: 10.1055/s-0043-121881
Original article
Eigentümer und Copyright ©Georg Thieme Verlag KG 2018

Validity of conventional endoscopy using “non-extension sign” for optical diagnosis of colorectal deep submucosal invasive cancer

Takashi Hisabe
Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Sumio Tsuda
Endoscopy unit, General Health Examination Center, Okayama Saiseikai General Hospital, Okayama, Japan
,
Toshio Hoashi
Hoashi Gastrointestinal Medical Clinic, Chikushino, Japan
,
Hiroshi Ishihara
Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Kazutomo Yamasaki
Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Tatsuhisa Yasaka
Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Fumihito Hirai
Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Toshiyuki Matsui
Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Kenshi Yao
Department of Endoscopy, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Hiroshi Tanabe
Department of Pathology, Fukuoka University Chikushi Hospital, Chikushino, Japan
,
Akinori Iwashita
Department of Pathology, Fukuoka University Chikushi Hospital, Chikushino, Japan
› Author Affiliations
Further Information

Publication History

submitted 08 June 2017

accepted after revision 19 September 2017

Publication Date:
01 February 2018 (online)

Abstract

Background and study aims The non-extension sign relates to a localized increase in thickness and rigidity due to deep submucosal invasive (SM-d: depth of 1000 μm or more) cancer. The present study aimed to evaluate the efficacy of the non-extension sign in assessing the optical diagnosis of colorectal SM-d cancer.

Patients and methods We retrospectively analyzed 309 patients with 315 early colorectal cancers that had been endoscopically or surgically resected. The non-extension sign was judged from chromoendoscopy (CE) using conventional white-light imaging with indigo carmine, and is taken to be positive when any one of the findings of rigidity of a circular arc, trapezoid elevation, or converging mucosal folds are seen. We assessed comparing the accuracy of CE, magnifying chromoendoscopy (M-CE), and magnifying narrow-band imaging (M-NBI) for the optical diagnosis of colorectal SM-d cancer.

Results Sensitivity, specificity, and accuracy for the diagnosis of SM-d cancer were 66.0 %, 95.8 %, and 86.3 % for CE; 80 %, 90.7 %, and 87.3 % for M-CE; and 65.0 %, 94.4 %, and 85.1 % for M-NBI, respectively. The specificity of CE was significantly higher than that of M-CE (P = 0.034). The sensitivity of M-CE was significantly higher than that of CE (P = 0.026). In a comparison of positive and negative groups for the non-extension sign in SM-d cancer, SM invasion was significantly deeper in the positive group than in the negative group (3012.5 μm vs 2002.4 μm, respectively; P < 0.0001) and the rate of lymphovascular invasion was significantly higher in the positive group than in the negative group (63.6 % vs 41.2 %, respectively; P = 0.032).

Conclusions The non-extension sign offers high diagnostic specificity for SM-d cancer, and surgery should be considered in patients with a positive non-extension sign.