Detection of micrometastases in peritoneal washings of pancreatic cancer patients by the reverse transcriptase polymerase chain reaction.

OBJECTIVE

Pancreatic cancer patients with positive (+) peritoneal cytology have a prognosis similar to stage IV patients. We studied the ability of quantitative real time-polymerase chain reaction (RT-PCR) to detect micrometastases in patients undergoing staging laparoscopy.

METHODS

Peritoneal washes were obtained prospectively from 35 consecutive patients with pancreatic adenocarcinoma undergoing staging laparoscopy and 16 patients undergoing laparoscopy for benign disease. Each sample was assessed by cytologic examination and RT-PCR analysis for tumor markers: CEA, CK7, Kras2, and MUC1. Markers and their combinations were evaluated on the basis of their deviance from the ideal marker.

RESULTS

Pathologic stages for pancreatic cancer patients were: 1A-1 (3%), IB-1 (3%), IIA-5 (15%), IIB-13 (38%), III-5 (15%), IV-9 (26%). Eight patients were cytology (+) and stages IIA-1, IIB-2, IV-5. Twenty-five patients were RT-PCR (+). The optimal threshold for cycle amplification was 35 based on a receiver operating characteristic curve. CEA had the best profile of sensitivity, specificity, PPV, NPV, and the smallest deviance.

CONCLUSION

RT-PCR using a panel of tumor markers, including CEA, was comparable in sensitivity, specificity, PPV, and NPV to cytology. RT-PCR could represent a more sensitive method for detection of subclinical peritoneal tumor dissemination; this may be useful in patient selection for operative management and clinical trials.