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.