Intensity modulated radiotherapy (IMRT) is used, where necessary, for bulky or complex-shaped, locally advanced, non-small cell lung cancer (NSCLC). We evaluate our real-world experience with radical radiotherapy including concurrent chemoradiation (CCRT), and analyse the impact of IMRT on survival outcomes in patients with larger volume disease. All patients treated between May 2011 and December 2017 were included. Analyses were conducted for factors affecting survival, including large volume disease that was defined as planning target volume (PTV) > 500 cc. In 184 patients with large volume disease, the median overall survival was 19.2 months, compared to 22 months seen with the overall cohort of 251 patients who received radical radiotherapy. PTV and using CCRT were significant predictors for survival. IMRT was used in 93 (50.5%) of 184 patients with large PTV. The patients treated using IMRT had significantly larger disease volume (median PTV = 859 vs 716 cc; p-value = 0.009) and more advanced stage (proportion of Stage IIIB: 56 vs 29%; p-value = 0.003) compared to patients treated with three-dimensional conformal radiotherapy. Yet, the outcomes with IMRT were non-inferior to those treated with 3DCRT. CCRT was used in 103 (56%) patients with large volume disease and resulted in a significantly better median survival of 24.9 months. The proportional benefit from CCRT was also greater than in the overall cohort. Despite being used for larger volume and more advanced NSCLC, inverse-planned IMRT resulted in non-inferior survival. IMRT enables the safe use of curative CCRT for large-volume, locally-advanced NSCLC.