Para-aortic lymph node dissection following neoadjuvant chemotherapy for type 4 or large type 3 gastric cancer with extensive lymph node metastasis.

BACKGROUND D2 and para-aortic lymph node dissection (PAND) following neoadjuvant chemotherapy (NAC) are reportedly effective for gastric cancer (GC) with extensive lymph node metastasis (ELM), such as para-aortic nodal metastasis or bulky nodal metastasis, around the major perigastric arteries. However, type 4 and large type 3 tumors were excluded from previous studies, as they are considered special subtypes that easily spread to the peritoneum. Whether or not PAND contributes to the survival of type 4 or large type 3GC with ELM is thus unclear. METHODS This study examined patients who underwent radical gastrectomy with D2 resection and PAND following NAC between 2002 and 2019. Patients were classified into the normal-type group and the type 4 or large type 3 group. The overall survival (OS) and prognostic factors were investigated. RESULTS Forty-nine patients were examined and classified into the normal-type group (34 patients) and type 4 or large type 3 group (15 patients). The 5-year OS rates of the normal-type and type 4 or large type 3 groups were 55.5% and 26.7%, respectively. Type 4 or large type 3 tumors were an independent risk factor for a poor prognosis in the multivariate analysis (hazard ratio: 2.506, 95% confidence interval: 1.111-5.650, and p = 0.027). CONCLUSIONS The prognosis of type 4 or large type 3 GC with ELM treated with radical gastrectomy with D2 and PAND after NAC was poor. Type 4 or large type 3 GC with ELM should be treated using a different strategy than the normal type with ELM.