Utility of tumor markers in determining resectability of pancreatic cancer.

HYPOTHESIS Despite advances in preoperative radiologic imaging, a significant fraction of potentially resectable pancreatic cancers are found to be unresectable at laparotomy. We tested the hypothesis that preoperative serum levels of CA19-9 (cancer antigen) and carcinoembryonic antigen will identify patients with unresectable pancreatic cancer despite radiologic staging demonstrating resectable disease. DESIGN AND SETTING Academic tertiary care referral center. PATIENTS From March 1, 1996, to July 31, 2002, 125 patients were identified who underwent surgical exploration for potentially resectable pancreatic cancer based on a preoperative computed tomographic scan; in 89 of them a preoperative tumor marker had been measured. MAIN OUTCOME MEASURES Preoperative tumor markers (CA19-9 and carcinoembryonic antigen) were correlated with extent of disease at exploration. As CA19-9 is excreted in the biliary system, CA19-9 adjusted for the degree of hyperbilirubinemia was determined and analyzed. RESULTS Of the 89 patients, 40 (45%) had localized disease and underwent resection, 25 (28%) had locally advanced (unresectable) disease, and 24 (27%) had metastatic disease. The mean adjusted CA19-9 level was significantly lower in those with localized disease than those with locally advanced (63 vs 592; P =.003) or metastatic (63 vs 1387; P<.001) disease. When a threshold adjusted CA19-9 level of 150 was used, the positive predictive value for determination of unresectable disease was 88%. Carcinoembryonic antigen level was not correlated with extent of disease. CONCLUSIONS Among the patients with resectable pancreatic cancer based on preoperative imaging studies, those with abnormally high serum levels of CA19-9 may have unresectable disease. These patients may benefit from additional staging modalities such as diagnostic laparoscopy to avoid unnecessary laparotomy.