Radical radiotherapy of inoperable non-small cell lung cancer. Irradiation techniques and tumor characteristics in relation to local control and survival.

The relation between tumor characteristics, irradiation technique, local tumor control and survival was retrospectively studied in 323 patients with non-small cell lung cancer who started radical radiotherapy in 1974-1981. At that time three non-randomized different fractionation schedules were used: 16 x 3.25 Gy, total dose 52 Gy, 3 fractions/week (schedule 1), 11 x 4 Gy, total dose 44 Gy, 2 fractions/week (schedule 2) and 25 x 2 Gy, total dose 50 Gy, 5 fractions/week (schedule 3). The highest survival rates were observed in the patient group treated according to schedule 2. The 2-year survival rate was 30% compared with 18% and 6% in the patients treated according to schedule 1 and 3 respectively. However, this can at least partly be explained by patient selection. A correlation between size of the tumor, target volume and survival was observed: the larger the tumor, the poorer the survival. Pleural effusion showed to be an unfavorable prognostic factor. The prognosis of inoperable lung cancer on the whole remained poor: the 1-year survival rate was 43% and 2-year survival rate 16%. Only 3% of the patients lived at least five years.