Plasma growth hormone and digital clubbing in carcinoma of the bronchus

Growth hormone is a secretory product of some primary bronchial neoplasms and has been associated with the development of hypertrophic pulmonary osteoarthropathy and acromegaly in occasional patients with such tumours; it has not, however, generally been considered important in the pathogenesis of digital clubbing. Plasma levels of growth hormone at the time of diagnostic bronchoscopy were measured in 60 patients with histologically proved bronchial carcinoma, divided according to whether clubbing was present (n = 21) or absent (n = 39), and in 13 control subjects undergoing the same procedure but with no neoplasm. The median plasma level of growth hormone ( and interquartile range) was 0.74 (0.5-1.0) mU/l in five control subjects with no pulmonary disease, 0.83 (0.4-1.3) mU/l in eight subjects with non-neoplastic pulmonary disease, 1.1 (0.6-3.3) mU/l in patients with carcinoma but without clubbing, and 3.1 (0.8-9.0) mU/l in 21 patients with carcinoma and clubbing. The highest growth hormone level was seen in a patient with a small cell carcinoma and pronounced clubbing; levels had fallen to normal by the time chemotherapy was completed and clubbing completely resolved. Thus growth hormone or a similar substance might have a role in the pathogenesis of clubbing in patients with bronchial neoplasms.