Effects of intensive chemotherapy on respiratory function in patients with small cell carcinoma of the lung

The lung function of 30 consecutive patients with small cell carcinoma of the lung was evaluated before and 3 months after initiation of intensive chemotherapy. Radiological evaluation of the therapeutic effect on the lung tumor was possible in 19 patients after 3 months. Six patients achieved complete normalization of the chest X-ray, 10 patients achieved more than 50% reduction of the tumor and no or minimal changes in the radiological image were observed in 3 patients. Before treatment a mixed pattern of obstructive and restrictive lung disease was observed in all patients. In the 16 patients who achieved partial or complete remission of the tumor normalization of the total lung capacity (P less than 0.02), vital capacity (P less than 0.02), FEV1 (P less than 0.02) and PEF (P less than 0.05) was observed independently of the degree of shrinkage of the tumor on chest roentgenogram, thus suggesting that the tumor was the major cause of the lung function impairment in these patients. The diffusion capacity and parameters reflecting the function of the small airways (RV/TLC% and MEF50) remained abnormal after treatment. Improvement of the lung function did not predict the individual duration of survival. However, the study proved that roentgenological normalization is paralleled by physiological normalization with the current treatment of this disease.