Title:
Clinical significance of wall invasion pattern of subserosa-invasive             gallbladder carcinoma.

Abstract:
We have previously classified wall invasion patterns of gallbladder carcinoma             (GBC) cases into two groups, i.e., the infiltrative growth type (IG type) and             destructive growth type (DG type). The DG type was significantly associated with             poor differentiation, aggressive infiltration and decreased postoperative survival             in terms of its histological differentiation, lymphatic invasion, venous invasion,             lymph node status, neural invasion and mode of subserosal infiltration. In the             present study, we analyzed 42 surgically-resected subserosal invasive gallbladder             adenocarcinomas, invading the perimuscular connective tissue (pT2). The cumulative             5-year survival rate in the series was 48.7%. Lymphatic invasion (p=0.021), venous             invasion (p=0.020), mode of subserosal infiltration (p<0.001), histological             differentiation (p=0.030) and biliary infiltration (p=0.007) were noted, respectively,             at a significantly higher incidence in more aggressive infiltration or poor differentiation             in the DG type. The cumulative 5-year survival rate of curative resection cases             was lower in patients with the DG type than in those with the IG type (68.9 versus             20.2%, respectively, p=0.006, log-rank test). On Cox's proportional hazard regression             modeling, the low degree of venous/perineural invasion and IG type of wall invasion             pattern were associated with a significant improvement in overall survival. Our             data suggest that the wall invasion pattern is an independent predictor of survival             in subserosal invasive GBC. Regarding the clinical application of our concept,             on the classification of patients with subserosal invasive GBC based on a combination             of the wall invasion pattern and lymph node status, the overall survival rate             in patients with the DG type and/or N2 metastasis (n=21) was lower than in patients             with the IG type and N0, 1 metastasis (n=21) (p=0.0023, log-rank test). The wall             invasion pattern could contribute to decision-making concerning curative resection             for subserosal invasive GBC.