Background: Patients with hepatocellular carcinoma (HCC) often develop recurrences after curative resection or liver transplantation. Therefore, tumor cell dissemination must have occurred preoperatively or intraoperatively. Current staging methods cannot reliably detect micrometastasis. Reverse transcription-polymerase chain reaction (RT-PCR) for alpha-fetoprotein (AFP) has been used to detect circulating liver cancer cells, but results in blood samples have been contradictory.
Hypothesis: AFP-RT-PCR is a specific and sensitive assay for the detection of disseminated tumor cells in central venous blood and bone marrow samples of patients with HCC and has prognostic relevance.
Design: Prospective consecutive series.
Setting: University hospital.
Patients and methods: We performed preoperative, intraoperative, and postoperative analyses of central venous blood samples and preoperative analysis of bone marrow samples of patients with HCC and patients without malignant disease, using a modified AFP-RT-PCR method. Preoperative serum AFP levels were measured. Clinical follow-up ranged from 4 to 20 months.
Main outcome measures: Sensitivity and specificity of AFP-RT-PCR, correlation of AFP-RT-PCR results to tumor stage and tumor recurrence.
Results: In serial dilution experiments, 50 AFP-expressing HepG2 cells were detected in 10 mL of blood. Peripheral blood samples of 20 healthy volunteers and bone marrow samples of 21 patients with benign diseases consistently tested negative for AFP, whereas 4 of 24 patients with HCC showed AFP expression in bone marrow samples. All these patients had advanced disease; however, correlation of positive RT-PCR results to tumor stage was not significant (P = .07). One of the 4 AFP-positive patients developed an intrahepatic recurrence soon after liver transplantation. Central venous blood of patients with HCC (n = 24) and patients with benign liver diseases (n = 13) equally demonstrated AFP-expressing cells. There was no correlation of RT-PCR results to serum AFP levels.
Conclusions: Perioperative screening for micrometastasis in bone marrow of patients with HCC is sensitive and specific with AFP-RT-PCR and may have prognostic relevance. Alpha-fetoprotein is not a suitable marker for the detection of tumor cells in central venous blood samples.