Presence of minute cancer cell dissemination in peritoneal lavage fluid detected by reverse transcription PCR is an independent prognostic factor in patients with resectable pancreatic cancer

Background

Presence of minute cancer cell dissemination in peritoneal lavage fluid detected by reverse transcription polymerase chain reaction (RT-PCR) has been reported to be a reliable predictor of the prognosis in several kinds of cancers, but has not been determined in pancreatic cancer.

Methods

Peritoneal lavage fluid was harvested just after a laparotomy in 83 patients with adenocarcinoma of the pancreas. Half of the fluid was examined by cytology and the remaining half was used to measure carcinoembryonic antigen/β-2-microglobulin (β2M) mRNA expression. Patients were followed after surgery to evaluate its clinical significance.

Results

Among 83 patients, 3 were cytologically positive (CY+), while 23 were positive by RT-PCR (PCR+). Seventy-one patients underwent a surgical resection whereas 12 were unresectable. Because 2 were CY+ among the 71 operated patients, the remaining 69 CY– patients were further investigated. Among those 69 patients, PCR+ was observed in 15 patients, whose incidence of postoperative peritoneal recurrence was significantly higher than that in PCR– patients (21% vs 4% at 3 years; P = .039). Moreover, both the recurrence-free rate in the abdominal cavity (peritoneal or local recurrence, excluding liver metastases) and the overall survival rate were better in PCR– patients than PCR+ patients (78% vs 33%, P = .0045 and 67% vs 46%, P = .0151). A multivariate analysis revealed positive lymph node metastases (hazard ratio; 5.18) and positive RT-PCR (hazard ratio; 3.65) were independent prognostic factors.

Conclusion

The RT-PCR–based cancer cell detection was an independent prognostic factor in patients with resectable adenocarcinoma of the pancreas and had close association with local or peritoneal recurrence.