[Therapeutic Value of Lymphadenectomy and Prediction of Station No. 1 Lymph Node Metastasis in Lower-Third Gastric Cancers].

ABSTRACT

BACKGROUND: According to the 14th Japanese Classification of Gastric Carcinoma(JCGC), station No. 1 lymphadenectomy for distal gastrectomy was included in the D1 level, though the 13th JCGC classified station No. 1 lymphadenectomy to the D2 level in patients with primary lower-third gastric cancer (LGC). This study was designed to re-evaluate the therapeutic value of lymphadenectomy, and to clarify the possible risk factors for station No. 1 lymph node metastasis (LNM) in LGC. METHODS: Between 1997 and 2014, 1,875 consecutive patients with gastric cancer underwent curative gastrectomy with radical lymphadenectomy. Of these, 344 patients who had a tumor located in the lower (L) or lower-duodenum (LD) area were analyzed retrospectively. RESULTS: 1) The therapeutic value of lymphadenectomy of stations No. 6, No. 3, No. 8a, No. 5, No. 4d, and No. 1 lymph nodes was proved to be higher than that of lymphadenectomy of other station lymph nodes. Patients with station No. 1 LNM had a significantly higher incidence of undifferentiated type, lymphatic invasion, venous invasion, and pT2-4 tumor. 2) Regarding factors to predict station No. 1 LNM in LGC, there was no station No. 1 LNM in patients with both early and differentiated type LGC. Distance from the pylorus to the tumor center (DPT) significantly correlated with station No. 1 LNM. Particularly, there was no station No. 1 LNM in patients with early LGC and DPT<50 mm. CONCLUSIONS: In patients with early and differentiated type LGC and DPT<50 mm, limited surgery to omit station No. 1 lymphadenectomy might be possible.