Prognostic value of calculated tumor volume (cTV) in T4 or N3 advanced gastric cancer

Background: To evaluate the prognostic value of tumor volume in gastric cancer, we assess calculated tumor volume (cTV) based on pathologic reviews and investigate its correlation with long-term outcome of patients who underwent curative gastrectomy. Methods: : In total, 574 gastric cancer patients who underwent curative gastrectomy in a single institution between January 2012 and December 2015 were enrolled and divided into subgroups (cTV group) according to cTV using pathologic tumor size and depth. The cutoff values of calculated cTV for subgroups were designated as 0-160.0 for the cTV1 group, 160.1-468.0 for the cTV2 group, and ≥ 468.1 for the cTV3 group. Results: : Among enrolled patients, 403 (70.2%) were in the cTV1 group, 116 (20.2%) were in the cTV2 group, and 55 (9.6%) were in the cTV3 group. The 5-year overall survival rate of V groups were significantly different: 94.4% in cTV1, 86.2% in cTV2, and 69.3% in cTV3. In the univariate analysis, the cTV groups were associated with poor overall survival (OS) and disease-free survival (DFS) with age, tumor location, histologic type, Lauren classification, T stage, and N stage. In the multivariate analysis, the cTV group was an independent prognostic factor for OS (HR 2.50, P=0.049) and DFS (HR 2.25, P=0.044). In the subgroup analysis, there was a significant difference according to the cTV group in both OS and DFS in T4 and N3 gastric cancers. Conclusions: : Tumor volume plays an additive role in predicting survival in patients with gastric cancer. Moreover, the calculated tumor volume is significant parameter associated with poor prognosis in T4 and N3 advanced gastric cancer regardless of TNM stage.