Beyond PERISCOPE II: Redesigning Peritoneal-Directed Treatment for Gastric Cancer.

Peritoneal metastases remain a major therapeutic challenge in gastric cancer. PERISCOPE II provided the first direct randomised comparison of an integrated operative strategy with continued systemic therapy in patients selected for limited peritoneal disease. Gastrectomy, cytoreductive surgery (CRS) and sequential heated oxaliplatin-normothermic docetaxel did not improve survival and caused substantial morbidity. The trial result should thus exclude routine adoption of that pathway, but it should not be interpreted as proof that every form of peritoneal-directed treatment is futile. Its multicomponent intervention was undertaken after brief systemic treatment, without mandatory laparoscopic confirmation of peritoneal response before randomisation, and frequently disrupted further systemic therapy. Meanwhile, DRAGON-01 has shown that repeated normothermic intraperitoneal paclitaxel can improve survival when added to systemic treatment, and STOPGAP has demonstrated the feasibility of serial laparoscopic reassessment and response-directed surgery in a Western pathway. Future trials should therefore separate two questions: whether intraperitoneal therapy adds benefit to contemporary biomarker-directed systemic treatment, and whether operative consolidation benefits the exceptional responders thereby identified. Surgery should become the consequence of demonstrated systemic and peritoneal response, not the intervention used to discover it.