Isotoxic Intensity Modulated Radiotherapy (IMRT) in Stage III Non Small Cell Lung Cancer (NSCLC) - A Feasibility Study

This study is for patients having a course of chest radiotherapy treatment after receiving chemotherapy for the treatment of non-small cell lung cancer. Patients with non-small cell lung cancer have a risk of the tumour in the lung recurring or progressing after treatment. In this study, we will investigate: * whether giving a more targeted and individualised type of chest irradiation or radiotherapy to the lung tumour (known as Isotoxic IMRT), is practical and whether it causes side effects which can be tolerated * whether this new method of delivering the radiotherapy can reduce the risk of the tumour in the lung recurring or progressing * whether survival can be improved by using this new radiotherapy method The dose of chest irradiation will be calculated specifically to suit patient's body shape, the position of the lung cancer, and how close healthy tissues are to the tumour. Radiotherapy will be delivered twice a day over a maximum period of 4.5 weeks. The duration of treatment will vary individually according to the delivered dose to the tumour area.