Phase II Clinical Trial of Postoperative S-1 Monotherapy for Gastric Cancer Patients with Free Intraperitoneal Cancer Cells Detected by Real-Time RT-PCR
We have previously reported the molecular detection of peritoneal micrometastases in patients with gastric cancer by quantifying carcinoembryonic antigen (CEA) mRNA in the peritoneal washes. Patients with CEA mRNA exceeding a cutoff value have a significant risk for developing peritoneal carcinomatosis, but optimal treatment for this population remains unknown.
CEA mRNA (+) patients with gastric cancer were treated postoperatively with S-1 monotherapy. Overall survival, the primary endpoint of this phase II trial, was compared with the historical control, which is comprised of CEA mRNA (+) patients who were not given postoperative chemotherapy.
A total of 32 patients with CEA mRNA (+) gastric cancer were enrolled. Twelve patients (37.5%) relapsed; ten showed peritoneal relapse. Three-year survival was similar between the study population and the historical control (67.3% vs. 67.1%, respectively).
S-1 monotherapy, which significantly reduced risk for recurrence in stage II/III gastric carcinoma in another phase III trial, seems not to be as effective in eradicating free cancer cells in the abdominal cavity.
KeywordsGastric Cancer Historical Control Peritoneal Carcinomatosis Postoperative Adjuvant Chemotherapy Peritoneal Wash
This study was supported in part by a grant from the Ministry of Health, Labor and Welfare, Japan and Ministry of Education, Science, Sports, Culture and Technology, Japan.
Conflict of interest
There are no conflicts of interest to report.
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