Fractionation and dose in thoracic radiotherapy.

The results of radiotherapy in non-small cell lung cancer confined to the mediastinum are disappointing. Conventional radiotherapy giving 60 Gy in 6 weeks gives primary tumour control of up to 23% with a 1 and 2-year survival of the order of 35% and 12%, respectively. Hyperfractionation--the giving of many small doses, and acceleration--the shortening of the overall duration of treatment, are two of the strategies now being tested. The CHART regime (Continuous, Hyperfractionated, Accelerated Radiotherapy) where 36 fractions are given over 12 consecutive days combines both features. In a pilot study this regime gave 40% local tumour control and a 1- and 2-year survival of 60% and 40%, respectively. Randomized controlled trials have commenced in the United Kingdom comparing CHART with conventional radiotherapy (60 Gy in 6 weeks). Over 300 patients have been entered in the first 2.5 years by 11 participating centres. It is hoped to accrue over 500 patients to this study in a period of 4 years.