[Angiotensin-converting enzyme activity during cytostatic therapy in patients with primary inoperable bronchial...

In 43 patients with inoperable bronchogenic carcinoma--32 small cell and 11 squamous or large cell--Angiotensin-Converting-Enzyme (ACE) activity in serum was determined before and every 3-5 weeks during cytotoxic chemotherapy. ACE-activity prior to therapy was 10.7 U +/- 1.17 SE as compared to the normal values 20.4 U +/- 1.8 SE which was statistically significant (p less than 0.01). There was no significant difference between the basal values of patients with small cell and not small cell-carcinoma of the lung. Only for patients with small cell-carcinoma of the lung a significant rise in ACE-activity could be obtained. Mean values of these patients reached normal levels in case they had complete remission, which was achieved in the limited disease group in 82% of patients. The present data suggest, that ACE-activities in serum correspond well to the clinical course in patients with small cell carcinoma of the lung. The decision on the individual mode of therapy may thus become more substantiated by serial determinations of ACE in the course of treatment.