Calcitonin concentrations in lung cancer and non-malignant pulmonary diseases.

The serum immunoreactive calcitonin (ICT) concentration was estimated in 107 patients with lung cancer of various cell types, 46 normal subjects and 24 non-cancer patients with various pulmonary diseases. Eighty-one of the cancer patients had localized lung cancer and the rest 26 primary lung cancer with metastases to other organs. The ICT was found significantly increased in the lung cancer patients. The highest ICT values were found in patients with lung cancer and metastases to other organs, especially to the liver. In localized disease, patients with small-cell carcinoma of the lung showed the highest, while those with adenocarcinoma and squamous-cell type demonstrated the lowest ICT concentrations. In 46 patients with lung cancer, serial determinations of serum ICT levels showed significantly decreased calcitonin levels in the patients who responded well to therapy with cytostatics, X-rays or both after more than 2 months of therapy. Fluctuations of ICT levels were in agreement with the regression or progression of the disease.