E365: Gastrectomy for Patients with Gastric Cancer Peritoneal Metastases: Safety and Outcomes from an Initial Experience

Gastric cancer with peritoneal metastases (GCPM) poses a significant clinical challenge. Cytoreductive surgery (CRS) with gastrectomy remains controversial and the addition of HIPEC has largely been reported by a single institution in the US. This study evaluated treatment of GCPM with curative intent at an NCI-designated comprehensive cancer center.

Methods:

A retrospective cohort study was conducted that included gastric adenocarcinoma patients with pathologically confirmed peritoneal metastases who underwent gastrectomy from 2018 to 2023. All patients selected for gastrectomy had a PCI of < 6, had to be free of ascites and have a lack of extraperitoneal metastatic disease. Descriptive statistics and time-to-event analyses were performed. 

Results: Twelve patients with GCPM met inclusion criteria. The median age was 66.5yr (IQR 56.5-76.5), 5 (41.7%) were female, and 8 (66.7%) were white. Most tumors were distal to the cardia/GEJ (n=9, 75%) and had signet ring histology (n=8, 66.7%). Nine (75%) patients had at least 1 laparoscopic HIPEC prior to CRS and 4 (33.3) patients underwent robotic-assisted gastrectomy/CRS. Total gastrectomy was performed in 7 (58.3%) patients and 3 (25%) patients had multivisceral resections. Median operative time was 424min (IQR 221-627), 75% of patients received intraperitoneal mitomycin C/cisplatin and 25% received mitomycin C alone. Median LOS was 9 days (IQR 1-18). Postoperative complications included 1 (8.3%) patient with an anastomotic leak requiring reoperation, 1 patient needing a drain for an intraabdominal fluid collection and 2 patients receiving a postoperative transfusion. One patient had a microscopically close proximal (esophageal) margin (< 1mm). Omental and ovarian disease was found in 41.7% (n=5) and 16.7% (n=2) of patients at the time of CRS, respectively. Eight (66.7%) patients had a PCI between 1-6 at CRS and the 4 patients who underwent robot-assisted gastrectomy had a PCI of 0. The Completeness of Cytoreduction (CC) Score was 0 for 10 (83.3) patients, 1 for 1 patient (8.3%) and not documented for 1 patient. 

Conclusions: Gastrectomy in patients with low volume peritoneal disease can be done as part of a comprehensive approach, including laparoscopic HIPEC, and minimally invasive gastrectomy, to treat patients with CGPM. The complications seen in this small cohort reflect similar complications to gastrectomy alone. These results suggest CRS/HIPEC with curative intent can be offered to highly selected patients.