Urine calcitonin levels in patients with bronchogenic carcinoma

We demonstrated previously that high serum calcitonin values in bronchogenic carcinoma are useful clinically as a parameter of progress of the disease and response to therapy. After developing a procedure for the measurement of calcitonin in urine, we studied serum and urine levels in 41 patients with lung cancer, using both a carboxyl terminus and a midportion recognizing antiserum. In general, midportion antiserum was more useful. Urine calcitonin measurements alone were superior to serum in terms of numbers of patients having increased values with one or both antisera (76% vs 46%). When both antisera were used to assay both serum and urine, 90% of patients had abnormal values. Once a tissue diagnosis has been established, the radioimmunoassay of urinary calcitonin offers a new dimension to the utility of this hormone as a marker for bronchogenic carcinoma.