Multidisciplinary Symposium—lung Cancer

Accurate delineation of the radiotherapy target volume for lung cancer requires close collaboration between radiologists and radiation oncologists. A detailed knowledge of radiological anatomy is needed to avoid pitfalls in interpretation of CT images which are used to define the exact size and limits of the gross tumour volume for treatment planning. PET scanning can distinguish atelectasis from primary lung tumour and has been shown to outline the tumour more accurately, thereby reducing inter-observer variation in target definition. Movement of the target volume can be reduced using newly developed methods such as respiratory gating, active breathing control devices or deep inspiration breath hold. Reduction in motion is necessary to create smaller target volumes for dose escalation to improve local control. The key to improved cure rates for non-small cell lung cancer lies in accurate target volume definition without which sophisticated conformal radiotherapy will be delivered as a geographical miss.