Clinical Significance of Detection of Carcinoembryonic Antigen in Peritoneal Fluid by Reverse Transcription-Polymerase Chain Reaction in Patients with Gastric Cancer

In, Young Jun; Park, Ki Ho; Park, Ki Hyuk; Choi, Dong Rak; Joo, Dae Hyun; Lee, Han Il; Park, Sung Hwan; Yu, Yong Woon; Jun, Chang Ho

Abstract

PURPOSE: Free cancer cells in the peritoneal cavity exfoliated from a tumor are considered to be responsible for peritoneal dissemination in gastric cancer. To detect free cancer cells, a carcinoembryonic antigen (CEA) was introduced to the marker of gastric cancer. The clinical significance of detecting the carcinoembryonic antigen (CEA) mRNA in the peritoneal fluid was evaluated by RT-PCR in patients with gastric cancer.
METHODS
In 50 patients with gastric cancer who received a gastrectomy, the peritoneal washing fluids were obtained and the CEA mRNA was detected by RT-PCR and a cytological examination was taken, simultaneously. The results were correlated with the stage and the recurrence of peritoneal seeding.
RESULTS
Positive values of CEA mRNA from the peritoneal washing fluids were observed in 24% (12/50) of patients with gastric cancer but of 4% (2/50) showed peritoneal cytology. There were 8 cases of peritoneal seeding in the follow-up and 6 cases of them presented positive CEA mRNA values (50%, 6/12). According to the stage, positive CEA mRNA values from the peritoneal washing fluids were found in 9% (2/21) in stage I, 20% (2/10) in stage II, 33% (5/15) in stage III and 75% (3/4) in stage IV (P=0.030). In the T classification, positive CEA mRNA values were found in 13% (2/15) in T1, 10% (1/10) in T2, 30% (7/23) in T3 and 100% (2/2) in T4 (P=0.031). In the N classification, positive CEA mRNA values were found in 15% (4/26) in N0, 20% (3/15) in N1, 40% (2/5) in N2 and 75% (3/4) in N3 (P=0.055).
CONCLUSION
These results suggest that the detection of CEA mRNA by RT-PCR in peritoneal fluid of gastric cancer patients was more sensitive than the peritoneal cytology, and may have a role in selecting patients with a poor prognosis who may benefit from adjuvant therapy.