Preoperative N stage evaluation in advanced gastric cancer patients using multidetector CT: can the sum of the diameters of metastatic LNs be used for N stage evaluation?. Issue 10 (October 2019) - You, J.M.
Abstract : AIM: To compare the diagnostic performance of total counts of metastatic lymph nodes (LN-sum) and conventional multidetector (MD) computed tomography (CT) staging in the nodal evaluation of advanced gastric cancer (AGC) patients. MATERIALS AND METHODS: In total, 127 consecutive patients who underwent preoperative MDCT and gastrectomy for AGC were identified. Metastatic LNs on MDCT were defined as LNs with a short axis ≥8 mm, marked or heterogeneous enhancement, and morphological features (central necrosis, round shape, clustering). The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the N-stage using LN-sum and conventional MDCT staging were generated and compared. In addition, metastatic LN counts between the MDCT and the histopathological examinations and correlation between LN-sum and histopathological nodal status were analysed. RESULTS: The total counts of metastatic LNs on MDCT was significantly smaller than those detected in histopathological assessments ( p< 0.0001). LN-sum showed significant correlation with the pathological N stage and the number of metastatic LNs (rho = 0.69, 0.73, p< 0.0001). The areas under the receiver operating characteristic curve were 0.896, and 0.835, for N stage ≥N2 and N3, with cut-off values of 12.5 and 23.5 mm, respectively. LN-sum provided better diagnostic performance than conventional MDCT staging for discriminating N0–2 versus N3; sensitivity, accuracy, PPV and NPV of LN-sum were significantly higher (80.4 versus 52.2%, 81.1 versus 68.5%, 71.2 versus 57.1%, and 88 versus 74.1%). CONCLUSION: LN-sum may be sufficiently useful in assessing the N3 stage of AGC and may help to plan appropriate therapy for AGC patients. Highlights: LN-sums showed significant correlation with the pathological N stages. LN‐sum was more effective for discriminating N0‐2 vs. N3 than conventional MDCT staging in the advanced gastric cancer. LN-sum makes it possible to identify patients of high risk and select the optimal therapeutic plan.