Purpose: Outcome for patients with biliary-pancreatic cancer is still poor, despite curative operation. We investigated the clinical significance of molecular detection of circulating cancer cells in the blood as an early indicator of relapse during follow-up of patients who underwent a curative operation for biliary-pancreatic cancer.
Patients and methods: We followed 53 patients who underwent a curative operation for biliary-pancreatic cancer between 1996 and 2001. We used reverse transcription-PCR in the peripheral blood to evaluate carcinoembryonic antigen (CEA) mRNA expression for molecular detection of circulating cancer cells. Follow-up examinations every 3 months after surgery included CEA mRNA expression in the blood, serum CEA, serum carbohydrate antigen 19-9 (CA19-9), and computed tomography or magnetic resonance imaging.
Results: Sixteen of 53 patients (30.2%) were diagnosed with a recurrence by imaging studies. The CEA mRNA detection rate in the peripheral blood of these 16 patients was 75% compared with 5.4% in the 37 patients without relapse (P < 0.001). Sensitivity of CEA mRNA, CEA, and CA19-9 serum levels was 75.0%, 50.0%, and 68.8%, respectively. Similarly, specificity was 94.6%, 64.9%, and 81.1%, respectively. CEA mRNA was expressed in the blood, even though tumor markers CEA and CA19-9 were within the normal range in patients with relapse. CEA mRNA expression in the blood, as well as the serum level of CA19-9, tended to be detected a few months earlier than detection by imaging modalities.
Conclusions: During the follow-up of patients who undergo a curative operation for biliary-pancreatic cancer, CEA mRNA expression in the peripheral blood might be a useful and early indicator of relapse.