Plasma and tumor ACTH in carcinoma of the lung

Plasma and tissue contents of immunoreactive ACTH were determined in 100 patients undergoing surgical resection for lung cancer. ACTH was detectable (greater than 1 ng ACTH equivalent/g wet weight) tissue in 47 of 49 specimens of epidermoid carcinoma, in 15 of 17 specimens of adenocarcinoma and in 7 of 8 specimens of large cell carcinoma; the median concentrations in these three tumor types were 8, 3 and 9 ng/g, respectively. Patients with oat cell carcinoma were not considered candidates for curative resection and are not included in this series. ACTH was not detectable in 36 specimens of apparently normal lung tissue from the same lobe but distant from the tumor and ranged up to 6 ng/g in 14 other specimens. One-half of patients with epidermoid carcinoma but only one-quarter of those with adenocarcinoma had preoperative plasma levels exceeding 250 ng/L plasma. About 75% of patients survived for at least one year whether preoperative plasma levels were greater than 400 ng/L or less than 200 ng/L. In only 4 of 21 patients with preoperative levels greater than 300 ng/L did the plasma fall by at least one-half in the immediate postoperative period. It is concluded that measurement of preoperative and postoperative plasma immunoreactive ACTH does not have a prognostic value for remission or long term survival in lung cancer, probably because it is unlikely that the tumor per se is the sole source accounting for the elevated levels generally observed in this condition.