ABSTRACT
In patients with poor lung function (forced expiratory volume in one second [FEV1] 1.0 L) a balance between attempting cure and maintaining lung function must be sought. Although there is no agreed lower cut-off below which radiation is contraindicated, a curative dose of radiotherapy is likely to significantly impair lung function in patients with an FEV1 of 0.6 L or grade 4 dyspnoea on the Medical Research Council (MRC) scale.
