Superselective Transarterial Chemoembolization (SSTACE) for Conversion Therapy in Locally Advanced Unresectable Gastric or Gastroesophageal Junction Adenocarcinoma: A Retrospective Cohort Study

Background Among patients diagnosed with locally advanced unresectable gastric or gastroesophageal junction adenocarcinoma treated with systemic chemotherapy/immunotherapy, suboptimal efficacy of conversion therapy has been observed, characterized by low surgical conversion rates and poor prognosis. This study aims to investigate the effectiveness and safety of superselective transarterial chemoembolization (SSTACE) in the management of this patient population. Methods This retrospective study included patients diagnosed with locally advanced unresectable gastric cancer (GC) or gastroesophageal junction (GEJ) adenocarcinoma at the Affiliated Hospital of XXX between January 2019 and March 2025. All enrolled patients underwent a single session of SSTACE, followed by surgical resectability assessment one month later. Those deemed resectable subsequently underwent gastrectomy with D2 lymphadenectomy, while unresectable cases received alternative conversion therapies. The primary endpoint was R0 resection rate, with secondary endpoints including postoperative complication rate, tumor regression rate after chemoembolization, and pathological complete response (pCR) rate. Results This retrospective study enrolled 16 patients who underwent SSTACE. The R0 resection rate was 75% (12/16), with a tumor regression rate of 50% following SSTACE. Twelve patients (75%) achieved successful conversion therapy and underwent gastrectomy with D2 lymphadenectomy, among whom three attained pCR, yielding a pCR rate of 18.8% (3/16). All SSTACE-related adverse events were manageable, with the most common being vomiting (43.8%, 7/16), nausea (37.5%, 6/16), and abdominal pain (37.5%, 6/16). No cases of hepatic dysfunction were observed. Furthermore, no serious surgical complications occurred in any operated patients. Conclusions SSTACE may enable patients with locally advanced unresectable GC or GEJ cancer who have demonstrated suboptimal response to systemic chemotherapy/immunotherapy to achieve higher rates of surgical conversion and R0 resection, while maintaining a favorable safety profile, potentially emerging as a novel therapeutic option for this patient population.