Molecular detection of occult cancer cells in patients with liver tumors treated by local ablation therapy

Purpose: We aimed to clarify the possibility of hematogenous spreading of cancer cells by microwave coagulation therapy (MCT) and radio-frequency ablation (RFA) for liver cancers. Molecular marker: Carcinoembryonic antigen (CEA) mRNA and melanoma antigen-3 (MAGE-3) mRNA were selected as a genetic marker. PCR method: Blood samples were collected before, during and just after the treatments. Genetic markers were examined using LightCycler reverse transcriptase–polymerase chain reaction (RT–PCR) assay with SYBR Green I. The samples with both positive markers were defined as genetic positive. Molecular metastasis and recurrence: We evaluated peripheral blood samples of 70 patients with liver tumors; 64 hepatocellular carcinomas (HCCs), 1 cholangiocellular carcinoma (CCC), and 5 metastatic liver tumors (MLTs). Genetic positive rates in RT–PCR assay before treatment were 42.2% in HCC, 0% in CCC, and 20% in MLT. Among genetic negative patients before operation, 45% of patients in MCT and 29% in RFA changed to genetic positive as a result of the procedures. Recurrence rates were 55% and 50% in MCT and 43% and 88% in RFA of the patients assessed negative to negative and negative to positive, respectively. Conclusion: Local ablation therapies may promote hematogenous seeding of cancer cells.