Hematogenous dissemination of hepatocytes and tumor cells after surgical resection of hepatocellular carcinoma: a quantitative analysis

Abstract

The only hope of long-term survival for patients with hepatocellular carcinoma (HCC) is surgical resection or liver transplantation. However, recurrence or metastasis formation is common after surgery. We aim to assess whether surgical resection leads to hematogenous dissemination of malignant and nontumor hepatocytes and determine the quantity and timing of hepatocyte shedding into the circulation. Using semiquantitative reverse transcription-PCR for alpha-fetoprotein (afp) and albumin (alb) mRNAs, we measured the mass of malignant and nontumor hepatocytes in 53 peripheral blood samples collected preoperatively, intraoperatively, and postoperatively from 13 HCC patients. We compared these data with those in 54 control samples collected from 24 healthy subjects and patients with chronic hepatitis/cirrhosis and 10 hepatocellular adenoma patients who underwent resection. Clinicopathological information of HCC patients was obtained during 3-year follow-up. In 100% (23 of 23) of HCC and adenoma patients, alb mRNA levels increased 10-10(6)-fold intraoperatively and then markedly declined within 8 weeks after operation. Levels of afp mRNA increased 5-7600-fold preoperatively in 8% (1 of 13) and postoperatively in 70% (9 of 13) of HCC patients. All five HCC patients with persistently elevated afp mRNA levels died from intrahepatic/extrahepatic metastasis, liver recurrence, or persistent HCC within 1 year after surgery. The absence/clearance of afp mRNA in 75 % (six of eight) of survivors was strongly associated with the absence of metastasis/recurrence (P = 0.02). We present evidence that alb-expressing hepatocytes are released intraoperatively into the circulation, and afp-expressing tumor cells are disseminated mostly postoperatively that may potentially be the source of recurrence or metastasis. Sequential quantification of both alb and afp mRNAs may provide insights for risk assessment and prognostic indication.