Small (≤ 2 cm) Carcinomas in the Proximal Stomach Demonstrate Distinct Clinicopathologic Features from Those in the Distal and Corpus: A Proposal for Classification of Gastric Cancer by Location
Q Huang, J Shi, Q Sun, HP Yu, JY Chen, HY Wu, JK Gold, H Mashimo, CC Yu, GY Lauwers. Nanjing Drum Tower Hospital, Nanjing, China; VA Boston Healthcare System, West Roxbury, MA; Massachusetts General Hospital, Boston, MA
Background: The pathobiology of proximal gastric cancer (PGC) is suggested to be more akin to that of esophageal cancer. However, recent Asian and German studies show that the prognosis of PGC is similar to neither esophageal nor distal gastric cancer (DGC). Because the incidence of PGC is high and the optimal therapeutic strategy is debated, we aimed to compare clinicopathologic features between small PGCs and non-PGCs with the hypothesis that they may be dissimilar.
Design: Surgically resected small (≤ 2 cm) gastric cancer (GC) treated at the Nanjing Drum Tower Hospital in China from 2004 through 2009 was searched in pathology files, and divided by location as PGC (epicenter within 3 cm below the gastroesophageal junction), DGC (from the incisura to the pylorus), and CGC (corpus gastric cancer, between PGC and DGC). Exclusion criteria were: 1) size >2 cm, 2) cases with neoadjuvant therapy, 3) epicenter within the esophagus, 4) prior resection, 5) absence of archived tissues. Tumor classifications followed the 2010 WHO Classification of Tumours of the Digestive System. All tumors were staged according to the AJCC 7. Clinicopathologic variables between groups were compared with the Fisher's exact and two-tailed Student's t tests. P <0.05 was considered statistically significant.
Results: Of 1,973 consecutive GC resections, 226 (12%) were eligible with 73 (32%) PGCs, 129 (57%) DGCs, and 24 (11%) CGCs. PGCs were more polypoid and less ulcerated than non-PGCs (p < 0.05). They were better differentiation (p < 0.001) and more heterogeneous with adenosquamous, neuroendocrine, and medullary variants but fewer in signet-ring cell carcinoma than non-PGCs (p < 0.05). The frequency of adjacent gastric dysplasia was lower (p < 0.001) but the occurrence of gastritis cystica profunda was higher in PGCs than non-PGCs (p < 0.001). In contrast, no significant differences were noted in all clinicopathologic features between DGCs and CGCs groups, nor in patient age, gender, H pylori infection rate, status of adjacent mucosa (chronic inflammation, lymphoid follicle, intestinal metaplasia, and atrophy), tumor size, lymphovascular and perineural invasion, and tumor stage between PGCs and non-PGCs groups (p>0.05).
Conclusions: Small PGCs display distinct clinicopathologic characteristics, compared to non-PGCs. Given unique prognostic features, the results argue for considering PGC as a separate disease entity.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 89, Wednesday Afternoon