Biochemical markers in bronchial carcinoma.

A total of 107 patients with bronchial carcinoma have been studied for the presence of potential circulating tumour markers which might be used as indicators of recurrence after primary treatment. Plasma carcinoembryonic antigen (CEA) levels were estimated in every patient and, after a preliminary hormone screening study, plasma calcitonin (CT) and parathyroid hormone (PTH) levels were assayed in 66 patients. Oat-cell tumours proved to be of particular interest in that CEA levels greater than 40 microgram/l were measured (initially or subsequently) in 40.6 percent and CT levels were elevated in 75 percent. Longitudinal studies point towards the possible use of elevated marker levels as guides to therapy when all other features of recurrent disease are lacking. It is clear that no ideal tumour marker exists for bronchial carcinoma but in an individual case an abnormal level of one or more marker substances may provide a valuable aid to treatment.