[1770] Geographic Differences of Frequency and Associations with Invasive Carcinoma in the Two Distinct Carcinogenetic Pathways (Conventional Dysplasia Versus Tumoral Intraepithelial Neoplasia) in the Gallbladder

Jiyeon Hyeon, Kee-Taek Jang, Takuma Tajiri, Nobu Ohike, Dursan Nevra, Pelin Bagci, Volkan N Adsay. Samsung Medical Center, Seoul, Korea; Showa, Tokyo, Japan; Emory, Atlanta, GA

Background: It is now well established that there are 2 distinct types of the intraepithelial neoplasm (IN) recognized in various organs including the gallbladder (GB): One, represented as conventional dysplasia (flat, non-tumoral IN; or FIN) and the other tumoral type, (“adenoma” or “intracystic papillary neoplasm and carcinoma” in WHO-2010, or as recently proposed intracholecystic papillary-tubular neoplasm-ICPN [in AJSP, 2012]). There was no data in the literature on the geographic differences (East vs West) of FIN vs ICPN in GB carcinogenesis.
Design: We searched total 30,249 cholecystectomy cases from Korea (10,028, Japan (2,198), USA (7,069) and Turkey (10,954) and collected those had the diagnostic terms of “dysplasia, adenoma, papillary tumor or neoplasm”. We compared the frequency and relative proportion of the two precursor lesions (FIN vs. ICPN), as well as the frequency of associated invasive carcinoma between the East (Korea, Japan) and the West (USA, Turkey).
Results: I. Although the overall frequency of all IN (regardless of FIN or ICPN) was higher in the East (3.8%) than the West (0.7%), the INs in the East were predominantly of ICPN type (53%; 245/467), whereas the ICPNs constituted only 26% in the West (p=0.00), with the remaining 74% being FINs. II. Invasive carcinomas were more commonly accompanied by FIN than ICPN in both the East and the West: 73% of the invasive cases of the West, and 80% of those in the East had an FIN lesion in adjacent GB, as opposed to 27% and 20% had ICPN, respectively. Frequency of invasion was more commonly identified in cases with FIN in the East than the West (87 vs. 58 %; p=0.00). In contrast, ICPNs appeared to be more commonly associated with invasion in the West than the East (West vs. East: 42 vs. 29%); however this did not reach statistical significance (p=0.13).
Conclusions: There are significant geographic differences in the relative incidence of the two distinct types of IN (ICPN vs FIN) in the GB, and their rate of and association with invasive carcinoma. Both the overall incidence of ICPNs and its relative proportion in IN was higher in the East than the West, with the ICPNs constituting 53% of the GB INs in the East and only 26% in the West. In both geographic regions, invasive carcinomas are more closely associated with FINs than ICPNs. However, ICPNs, although lower in relative frequency, may be more prone to advance into invasive carcinoma in the West.
Category: Pancreas

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 126, Wednesday Afternoon


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