Intraperitoneal chemotherapy may have clinical benefits over standard treatment in gastric cancer patients with peritoneal metastasis, exploratory analyses of a randomized clinical trial suggest.
Although it failed to demonstrate a statistical overall survival advantage versus standard chemotherapy in the primary analysis of the phase 3 trial, intraperitoneal treatment had a significantly longer overall survival in an analysis adjusted for presence of ascites, study investigators reported.
In addition, the 3-year overall survival rate was significantly higher in the intraperitoneal arm of the trial, according to Hironori Ishigami, MD, PhD, of the University of Tokyo, and coinvestigators.
“Considering the results of these analyses, the efficacy of the IP [intraperitoneal] regimen seems underestimated by the primary analysis,” Dr. Ishigami and coauthors wrote in the Journal of Clinical Oncology.
The main culprits were an imbalance in ascites between arms, and crossover from standard therapy to the intraperitoneal arm, they added.
The phase 3 trial included 183 patients with gastric cancer and peritoneal metastases who had less than 2 months of prior chemotherapy. They were randomly assigned to receive either intraperitoneal and intravenous paclitaxel plus S-1 (tegafur/gimeracil/oteracil) or standard S-1 plus cisplatin.
Median survival was 17.7 months in the intraperitoneal arm, and 15.2 months in the standard-treatment arm (hazard ratio, 0.72; P = .08), Dr. Ishigami and associates reported.