Identifying multiple swollen lymph nodes on preoperative computed tomography is associated with poor prognosis along with pathological extensive nodal metastasis in locally advanced gastric cancer

Advanced gastric cancer with extensive lymph node (LN) metastasis is associated with poor outcomes even after R0 gastrectomy. Although multi-detector row computed tomography (MDCT) is the basis of preoperative LN staging, the diagnostic accuracy of pathologically extensive LN metastasis detection by MDCT remains unsatisfactory.We retrospectively evaluated diagnostic accuracy for pN2/3 disease by size and number of depicted LNs on MDCT in a single-center cohort of 421 patients with pT2-4 gastric carcinoma. The positive predictive value (PPV) was determined based on the number and short-axis diameter (SAD) of identified LNs, and oncological outcomes were also evaluated according to clinical LN status and pN categories.The PPV for detecting pN2/3 disease rose with the SAD value cut-off for one LN, reaching 84.6% at 10 mm with no further increase at 15 mm. However, the SAD cut-off value plateaued at 8 mm (91.3%) when at least two measurable LNs were identified on MDCT. Patients with two measurable LNs with SAD≥8 mm had significantly poorer 5-year overall and recurrence-free survival than patients with fewer than two measurable LNs in the pN2-3 disease. On multivariate analysis, two measurable LNs with SAD≥8 mm was an independent prognostic factor for overall and relapse-free survivals.Locally advanced gastric cancer with two measurable LNs with SAD≥8 mm on preoperative MDCT is highly associated with pN2/3 disease and poorer outcomes with upfront surgery. This criterion might be a reasonable indicator for identifying candidates for neoadjuvant treatment of advanced gastric cancer.