The combined modality approach with combination chemotherapy ("Comb" or "BACO") and radiotherapy was used in a pilot study comprising 35 evaluable patients with inoperable small-cell anaplastic carcinoma of the lung. Treatment strategy was based on prior assessment of prognostic factors such as histology, performance status and extent of disease. Median survival time was 39.8 weeks for "COMB" treated patients and 21.2 weeks for "BACO" treated patients. Although the combined modality approach has been very helpful against a variety of human cancers it should be used with caution since not all combination chemotherapy regimens are compatible with radiotherapy. Mechanisms of interactions between cytostatic agents and X-rays are discussed with regard to enhanced tumor cell kill and possible toxic side effects.