CT-Detected Extramural Vessel Invasion and Regional Lymph Node Involvement in Stage T4a Gastric Cancer for Predicting Progression-Free Survival.

Abstract

<b>OBJECTIVE.</b> This study aimed to investigate the 3-year progression-free survival (PFS) of patients with stage T4a gastric cancer with extramural vessel invasion (EMVI) detected with contrast-enhanced (CE) MDCT. In addition, we investigated the possibility that CT of EMVI could improve clinical nodal (N) staging. <b>MATERIALS AND METHODS.</b> This retrospective study included 143 patients with T4a gastric cancer. Clinical staging was performed with CE-MDCT. All patients underwent radical gastrectomy with extended lymphadenectomy, adjuvant chemotherapy, and conventional follow-up visits. Potential prognostic factors, including CE-MDCT-detected N status, pathologic N status, EMVI detected at CT, tumor location or growth pattern, histologic type or tumor differentiation, and tumor size, were recorded. Survival estimates for PFS were obtained using the Kaplan-Meier product limit for the following patient subgroups: EMVI positive-N positive, EMVI positive-N negative, EMVI negative-N positive, and EMVI negative-N negative. Hazard ratios for 3-year PFS were generated using a Cox proportional hazard regression analysis. <b>RESULTS.</b> The frequency of EMVI detected at CT was 55.9% (80/143). The 3-year PFS rates were 25.0% for the EMVI positive-N positive group, 53.1% for the EMVI positive-N negative group, 75.6% for the EMVI negative-N positive group, and 64.7% for the EMVI negative-N negative group. The EMVI positive-N positive subgroup 3-year PFS rate was significantly lower than that of the other three groups (<i>p</i> < 0.05, log-rank test). Using Cox proportional hazards regression analysis, EMVI positive-N positive status was found to be an independent factor for reduced 3-year PFS, with a hazard ratio of 2.169 (95% CI, 1.300-3.618; <i>p</i> = 0.003). <b>CONCLUSION.</b> EMVI detected at CT, combined with N status detected with CE-MDCT, could be used as a valuable preoperative prognostic factor in patients with T4a gastric cancer.