The impact of histological type on the accuracy of preoperative N staging in patients with gastric cancer

BACKGROUND: The low accuracy of preoperative diagnosis of lymph node metastasis in gastric cancer (GC) complicates decisions on patient indication for neoadjuvant chemotherapy. METHODS: We investigated the use of preoperative clinical diagnosis of lymph node involvement (cN) in GC patients compared with postoperative pathological diagnosis. RESULTS: In a series of 265 patients enrolled at the University of Yamanashi Hospital, the overall sensitivity was 44.4% and specificity was 93.4% of CT for detecting lymph node metastasis. The positive and negative predictive values were 80.0% and 73.8%, respectively. The negative predictive value was lower for undifferentiated adenocarcinoma than that for differentiated adenocarcinoma (64.9% vs. 78.7%, p = 0.034). In cT2 ≤ and cN2 ≤ GC, overdiagnosis of lymph node metastasis was significantly more frequent in patients with differentiated (50.0%) than in undifferentiated (13.3%) adenocarcinoma (p = 0.046). CONCLUSIONS: Diagnostic accuracy of lymph node involvement depended on histological type and cT-stage. Thus, considering preoperative histological type in GC, it may be useful to decide treatment plan.