Abstract: Objective: To assess the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) in treating intraperitoneal free cancer cells (IFCCs) and the feasibility of the cytological cure for peritoneal carcinomatosis (PC). Methods:Peritoneal lavage liq-uid (or ascites) from 45patients with PC were collected before and after intraoperative HIPEC to detect CEA mRNA and CK 20mRNA by peritoneal lavage cytology (PLC) test and simple or real-time reverse-transcription polymerase chain reaction (RT-PCR). The blood samples before and after HIPEC were also collected to detect serum tumor markers, including CEA, CA125, and CA 19- 9. Results:The positive rates of PLC and the RT-PCR of CEA and CK20mRNAs before and after HIPEC were93.3% (42/45) and 24.4% (11 /45) ( P< 0.001), 97.8% (44/45) and 84.4% (38/45) (P=0.058), and 95.6% (43/45) and 95.6% (43/45) (P=1.000), respectively. After HIPEC, 32.5% and30.0% of the patients showed a significant decrease in CEA and CK20mRNA levels, respectively (P<0.001 for both). More-over, the positive rate of serum CEA, CA125, and CA 19- 9 before and after HIPEC were 50% vs.23.6% (P=0.016), 52.6% vs.47.4% (P=0.409), and 36.8% vs.26.3% (P=0.121), respectively. Conclusion:HIPEC could effectively eradicate IFCCs and provide a feasible approach to achieve cytological cure for PC.