Hyperthermic Intraperitoneal Chemotherapy (HIPEC), Oncological Outcomes and Long-Term Survival among Patients with Gastric Cancer and Limited Peritoneal Disease Progression after Neoadjuvant Chemotherapy.

Introduction: The role of surgery in stage IV gastric cancer with peritoneal metastasis (PM) remains unclear. The objective of the current single-center study was to define the impact of gastrectomy with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) on outcomes among Central European GC patients with limited peritoneal disease progression after neoadjuvant chemotherapy (NAC).

Methods: Patients with histologically confirmed GC who underwent curative-intent multimodal treatment between 2013 and 2023 were included. Patients without adenocarcinoma, who did not undergo gastrectomy, had early (cT1) or metastatic GC at the time of initial diagnosis, who underwent multivisceral resection, incomplete cytoreduction or palliative care, died before planned curative-intent treatment, or had incomplete clinical or pathological missing information were excluded.

Results: A total of 74 patients who underwent curative-intent treatment for GC with PM were included in the final analytic cohort. Patients who underwent gastrectomy with CRS+HIPEC were less likely to achieve TOO (CRS+HIPEC: 28% vs. CRS: 57.1%, = 0.033) compared with individuals after CRS alone. Specifically, patients who underwent gastrectomy with CRS+HIPEC had a higher likelihood of postoperative complications (CRS+HIPEC: 48% vs. CRS: 20.4%, = 0.018) and longer hospital LOS (median, CRS+HIPEC: 12 vs. CRS: 10, = 0.019). While administration of HIPEC did not impact long-term survival (median OS, CRS+HIPEC: 16 months vs. CRS: 12 months, = 0.55), postoperative complications (median OS, CCI < 30:16 months vs. CCI > 30:5 months, = 0.024) and ICU stay (median OS, no ICU stay: 16 months vs. ICU stay: 5 months, = 0.008) were associated with worsened long-term survival among GC patients with PM.

Conclusions: Data from the current study demonstrated a lack of survival benefit among advanced GC patients with PM undergoing gastrectomy with CRS+HIPEC when compared with individuals after gastrectomy with CRS alone. Administration of perioperative chemotherapy and achievement of TO failed to withstand the peritoneal disease progression during NAC.