At diagnosis, 65% of 103 patients with
small cell carcinoma of the lung were found to have elevated plasma concentrations of
vasopressin-associated human
neurophysin (VP-HNP),
oxytocin-associated human
neurophysin (OT-HNP), or both, which were thought to be related to
tumor secretion of these
proteins. The remainder of patients were designated as nonsecretors (24%) or possible secretors (11%), depending upon plasma concentration of the
neurophysins prior to
therapy. There was a significantly higher percentage of secretors among patients with extensive disease (82%) than among those with limited disease (40%) (P = 0.001). However, within each stage group, there was no correlation between secretory status and response to
therapy, survival, or histologic subtype. In addition, patients who initially were nonsecretors or possible secretors maintained this status throughout the course of disease remission and subsequent relapse. These findings suggest the possibility of biochemical differences between
tumors which present as limited disease and those which present as extensive disease. The syndrome of inappropriate
antidiuretic hormone secretion (
SIADH) was infrequent in limited disease but was present in 33% of patients with extensive disease.
SIADH was not seen without VP-HNP elevation; however, with extensive disease, 49% of patients with elevated VP-HNP had
SIADH. In contrast, elevated plasma concentrations of the
neurophysins were seen in only 19.6% of 56 patients with non-
small cell carcinoma of the lung. The levels were in general lower than those in patients with
small cell carcinoma and were seen at approximately equal frequencies in each major cellular subtype.