Evaluation of the utility of a radioimmunoassay for serum CA 19-9 levels in patients before and after treatment of carcinoma of the pancreas.

By radioimmunoassay we determined circulating levels of a tumor-associated antigen, CA 19-9, in 47 patients with pancreatic adenocarcinoma, to learn if serial testing was useful in predicting prognosis or in detecting disease progression. Before treatment, 42 (89%) had an abnormal serum level, and 45 (96%) had an abnormal level at some time during the disease course. A pretreatment value of less than 1,000 U/mL (normal, less than or equal to 37 U/mL) was found in 38 patients; 20 (53%) had resectable disease. One of nine patients (11%) with a pretreatment value greater than 1,000 U/mL had resectable disease (P2 = .05). Among 14 patients who underwent pancreatectomy and were studied serially, the CA 19-9 level normalized in eight; seven (88%) survived greater than or equal to 18 months. Six patients whose levels did not normalize after pancreatectomy all died in less than 12 months (P2 less than .005). Greatly elevated levels occurred in 11 patients after pancreatectomy 1 to 7 months before clinically apparent recurrence. The other three patients without significant elevations remain clinically free of disease. The data suggest that serial determination of serum CA 19-9 levels are useful as a prognostic indicator and in detecting disease recurrence following pancreatectomy. Concurrent determinations of carcinoembryonic antigen (CEA) levels showed abnormal preoperative values in 28 of 46 patients tested (61%). Concurrent serial postoperative determinations of CEA were available in ten patients. Whereas CA 19-9 values clearly indicated eight recurrences, CEA was helpful in only four. In this small group of patients, CA 19-9 was a better predictor of recurrence.