Is the recent WHO histological classification for gastric cancer helpful for application to endoscopic resection?
BACKGROUND
Endoscopic resection is performed in undifferentiated-type early gastric cancer (UD-EGC), including poorly differentiated (PD) adenocarcinoma and signet ring cell (SRC) carcinoma. We previously found that different approaches are needed for PD adenocarcinoma and SRC carcinoma for curative resection. However, according to the 2010 WHO classification, diffuse-type PD adenocarcinoma and SRC carcinoma are categorized in the "poorly cohesive carcinomas." Thus, we assessed whether the WHO classification is helpful when endoscopic resection is performed for treatment of UD-EGC.


METHODS
We analyzed clinicopathological features of 1295 lesions with SRC carcinoma and PD adenocarcinoma treated by open surgery. We recategorized them into intestinal-type PD adenocarcinomas and poorly cohesive carcinomas (SRC carcinoma, diffuse-type PD adenocarcinoma). We also recategorized 176 lesions treated by endoscopic resection into intestinal-type PD adenocarcinomas and poorly cohesive carcinomas.


RESULTS
According to the open surgery data, the rates of lymph node metastasis (LNM) and lymphovascular invasion were significantly lower in SRC carcinoma than in diffuse-type and intestinal-type PD adenocarcinomas. The rates of LNM and lymphovascular invasion were significantly higher in diffuse-type PD adenocarcinoma than in SRC carcinoma. Endoscopic resection data showed no recurrence if the carcinoma was curatively resected. However, the commonest cause of noncurative resection was different in SRC carcinoma and PD adenocarcinoma. A positive lateral margin was the commonest cause in SRC carcinoma versus a positive vertical margin in both intestinal-type and diffuse-type PD adenocarcinoma.


CONCLUSIONS
The clinical behavior differs in diffuse-type PD adenocarcinoma and SRC carcinoma. On the basis of LNM and outcomes of endoscopic resection, the recent WHO classification may not be helpful when endoscopic resection is performed for treatment of UD-EGC.
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.|Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Yong Hoon
YH
Kim
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea. otilia94@yuhs.ac.|Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. otilia94@yuhs.ac.
Jie-Hyun
JH
Kim
Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.
HyunKi
H
Kim
Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.
Hoguen
H
Kim
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.
Yong Chan
YC
Lee
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.
Sang Kil
SK
Lee
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.
Sung Kwan
SK
Shin
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.
Jun Chul
JC
Park
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.
Hyun Soo
HS
Chung
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.|Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Jae Jun
JJ
Park
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.|Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Young Hoon
YH
Youn
Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 135-720, Korea.|Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Hyojin
H
Park
Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
Sung Hoon
SH
Noh
Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.|Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Seung Ho
SH
Choi
D000230:Adenocarcinoma / Q000145:classification / Q000556:secondary* / Q000601:surgery; D018279:Carcinoma, Signet Ring Cell / Q000145:classification / Q000556:secondary* / Q000601:surgery; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D005753:Gastric Mucosa / Q000473:pathology*; D005773:Gastroscopy; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D014944:World Health Organization
Early gastric cancer; Endoscopic resection; Lymph node metastasis; Undifferentiated