Successful laparoscopic conversion surgery for gastric cancer with para-aortic lymph node metastasis after third-line chemotherapy: a case report

We herein reported a case of advanced gastric cancer (GC) with para-aortic lymph node (PALN) metastases who successful achieved downstaging following systemic chemotherapy and underwent curative laparoscopic conversion surgery. A 74-year-old male patient diagnosed with advanced GC and PALN metastases [cT4N3M1(LYM), stage IVA] was administered chemotherapy and immunotherapy for 28 months. After 27 courses of nivolumab as third-line chemotherapy, PALN enlargement was resolved, for which conversion surgery was planned. Subsequently, laparoscopic distal D2 gastrectomy with sampling para-aortic lymphadenectomy was performed, after which a pathological diagnosis of type V moderately differentiated tubular adenocarcinoma with mucinous adenocarcinoma, stage ypT3 (SS), ly1c, and v0, was established. The pathological proximal and distal tumor margins were negative. One lymph node metastasis was observed (No. 6; 1/25). The sampled lymph nodes were negative (No. 16a1: 0/2). The therapeutic effect was categorized as Grade 1a. The postoperative course was uneventful, with the patient receiving nivolumab to control for potential PALN metastases. Postoperatively, no recurrence was observed over 11 months. Laparoscopic conversion gastrectomy was successfully performed in a patient with advanced GC that was originally unresectable, suggesting that minimally invasive surgery may be a good option for originally unresectable advanced GC that becomes resectable.