Tumor Size As A Prognostic Factor In Patients With Node-negative Gastric Cancer Invading The Muscularis Propria And Subserosal(pT_2-3N₀M₀Stage)

AIM: To explore the impact of tumor size on outcomes in patients with node-negativegastric cancer invading the muscularis propria and subserosal (pT2-3N0M0stage).METHODS: We retrospectively analyzed the clinical records of115patients ofpT2-3N0M0stage gastric cancer who underwent D2curative resection in our hospitalfrom January1995to December2005. Receiver-operating characteristic (ROC) curveanalysis was used to determine the appropriate cutoff value for tumor size, which ismeasured as maximum tumor diameter. Based on this cutoff value, patients weredivided into two groups: those with large-sized tumor s (LSTs) and those withsmall-sized tumors (SSTs). The correlations between other clinicopathologic factorsand tumor size were investigated, and the5-year overall survival (OS) rate wascompared between the two groups. Potential prognostic factors were evaluated byunivariate Kaplan-Meier survival analysis and multivariate Cox’s proportional hazardmodel analysis. The5-year OS rates in the two groups were compared according todepth of tumor invasion and histological type.RESULTS: The5-year OS rate of all patients was73.4%. The mean±SD tumor sizewas4.1±2.2cm, and the median tumor size was4.0cm. ROC analysis indicated thatthe sensitivity and specificity results for the appropriate tumor size cutoff value of3.7cm were80.0%and57.0%, respectively(AUC=0.768,95%CI：0.666-0.870；P=0.000). Using this cutoff value,62patients (53.9%) were LSTs (tumor size≥3.7cm)and53(46.1%) had SSTs (tumor size <3.7cm). Tumor size was significantlycorrelated with histological type (P=0.016), Bormann type (P=0.000), depth oftumor invasion (P=0.000). Patients with LSTs had a significantly lower5-year OS rate than those with SSTs (60.7%vs.88.4%, P=0.000). Multivariate analysis revealedthat the depth of tumor invasion, histological type and tumor size were independentprognostic factors. In patients with pT2N0M0stage tumors,5-year OS rates weresignificantly lower for LSTs than for SSTs (67.8%vs.89.5%, P=0.000). In patientswith undifferentiated type tumors,5-year OS rates were significantly lower for LSTsthan for SSTs (51.2%vs.83.5%, P=0.000).CONCLUSION: Using a tumor size cutoff value of3.7cm, tumor size is a prognosticfactor in patients with node-negative gastric cancer invading the muscularis propriaand subserosal (pT2-3N0M0stage). There was poorer prognosis in gastric cancerpatients with pT2N0M0stage or undifferentiated type, especially when tumor size≥3.7cm.