Serum testosterone:dihydrotestosterone ratio and CA 19-9 in the diagnosis of pancreatic cancer.

The testosterone:dihydrotestosterone ratio (T:DHT) and the antigenic marker CA 19-9 were studied in the serum of 21 male patients with pancreatic cancer and 62 controls with other gastrointestinal malignancies or benign pancreatobiliary disease. Specificity of the T:DHT ratio was 98%, significantly better than the specificity of CA 19-9 at both a 37 U/ml cutoff level (61%) and at 100 U/ml (79%). Sensitivity of the T:DHT ratio was 67%, and that of CA 19-9, 71% and 90% at the upper and lower cutoff levels, respectively. False-negative results of the T:DHT ratio were found predominantly in cases of advanced pancreatic cancer, whereas all four stage I patients had an abnormal (less than 5) T:DHT ratio. These results suggest that the T:DHT ratio is a useful marker for pancreatic cancer in males. It can be used alone or in combination with CA 19-9, and should be further evaluated in the differential diagnosis of patients with the early stages of this disease.