Correlation of β-tubulin III and ERCC1 mRNA expression to chemotherapy outcome of gastric cancer patients with malignant ascites

We sought to determine how intraperitoneal administration of docetaxel (DTX) or cisplatin (DDP) plus tegafur-gimeracil-oteracil potassium (S-1) related to the expression levels of two genes, TUBB3 and ERCC1, when given to gastric cancer patients with peritoneal carcinomatosis. DTX or DDP was administered intraperitoneally via an implanted catheter, whereas S-1 was orally administered. We developed a new response criterion through B ultrasound to evaluate treatment against malignant ascites. The primary endpoint for treatment effectiveness was the 1-year overall survival (OS) rate. The secondary endpoints were the response rate, efficacy against malignant ascites and treatment safety. These results were correlated to the expression levels of TUBB3 and ERCC1. Peritoneal carcinomatosis was synchronous and metachronous in 80% and 20% of patients, respectively. Patients who received selective intraperitoneal perfusion chemotherapy which took into account gene expression levels had a median survival time of 247.5 days. Clinical regression of ascites and related symptoms was observed in all patients. One patient experienced hematologic toxicity. Malignant ascites disappeared in one patient after treatment. Overall, the 1-year OS rate was 40%. Intraperitoneal DTX or DDP with oral S-1 was well tolerated, efficacious and safe in gastric cancer patients with peritoneal metastasis and correlated to gene expression levels.