Tumour-associated trypsin inhibitor (TATI) in patients with colorectal cancer: a comparison with CEA, CA 50 and CA 242.

A prospective study of 62 patients with colorectal cancer was carried out to evaluate the value of tumour-associated trypsin inhibitor (TATI) in the diagnosis and staging of this disease. The reference group consisted of 97 patients with benign gastrointestinal disease. Increased serum TATI levels were detected in 46 patients with colorectal cancer (sensitivity 74%), and the highest mean values were measured in the patients with stage II cancer. The frequency of elevated values was not affected by the stage of the disease, however. There were altogether 64 false positives (specificity 34%). In comparison to CEA and CA 242, TATI showed higher sensitivity at low (< 40%) specificity levels, but it was less sensitive at high (70-95%) specificity levels. The performance of the CA 50 test was poorest both at high and low specificity levels. The various combinations of TATI and other markers (two tests positive) did not offer any further advantage as compared to CEA alone. A marginally significant positive correlation (p = 0.07) was found between serum TATI and CEA values in colorectal cancer patients. The results suggest that TATI is a very sensitive marker in colorectal cancer, but its utility is limited because of its low specificity in symptomatic patients. Concomitant measurement of TATI and other markers does not seem to give any further benefit, and nor does TATI seem to have any significant value in staging of the disease. Our results also indicate that CEA is probably the best current test in colorectal cancer.