A preliminary evaluation of calcitonin and PDN-21 as tumor markers for lung cancer. EORTC Lung Cancer Working Party.

: Immunoreactive calcitonin (iCT) can be ectopically secreted by lung cancer cells and has been proposed as a tumor marker for bronchial neoplasms. Since PDN-21 (katacalcin or the carboxyl-terminal flanking peptide of the calcitonin gene) and CT are cosecreted in normal subjects and in patients with medullary thyroid carcinoma (MTC), we sought to determine the potential utility of PDN-21 as a tumor marker for lung cancer. We measured carcinoembryonic antigen (CEA), neurone-specific enolase (NSE), iCT, and PDN-21 in 119 to 378 healthy subjects, 88 to 91 patients with benign pulmonary disease, and 249 patients with advanced lung cancer (108 small cell lung cancers and 141 other forms). Tumor marker specificity was satisfactory: the percentage of increased values (greater than the 95th percentile of normal subjects) in patients with benign pulmonary diseases varied from 9% (NSE, PDN-21) to 12% (CEA). PDN-21 was a more sensitive marker for lung cancer than iCT: the percentage of increased values was 44% for PDN-21 versus 19% for iCT, and 51% versus 23% for the subgroup of patients with small cell lung cancer (SCLC). PDN-21 concentrations were increased in 69 (34%) of 202 patients with a normal iCT level, whereas iCT concentrations were increased in only six (4%) of 139 patients with a normal PDN-21 level. However, markedly elevated concentrations of the two markers generally occurred in the same patients and the correlation between the two markers was significant (rs = 0.60; P less than 0.01). PDN-21 provided complementary information to that from the classical markers NSE and CEA.(ABSTRACT TRUNCATED AT 250 WORDS)