In recent years, various novel techniques for radiation treatment of cancer patients have been introduced to clinical practice: intensity‐modulated radiation therapy (IMRT), intensity‐modulated arc therapy (IMAT), helical tomotherapy (HT), light ions irradiation, etc. Such variety of instrumentation possibilities requires some initial comparative assessment of which particular technique would be the most beneficial for a given patient case. In clinical practice a balanced trade‐off between homogeneous and sufficient tumour irradiation and maximal sparing of sensitive structures is needed. A dose quality factor (DQF) was introduced to evaluate the plan quality for different treatment techniques based on realistic clinical requirements for target and organs at risk irradiation. A correlation between plan quality quantified by DQF with some set of patient specific features characterised by patient feature factor (PFF) is analysed in a comparative planning studies for 15 patients with stage III inoperable non‐small cell lung cancer using 3D conformal technique, IMRT and HT. For this set of patients, PFF is chosen as the product of three patient characteristics: the target complexity parameter, overlap between target and lungs, and the ratio between involved and non‐involved lungs. Future work would require validation in larger patient data sets, other disease sites and weighting of different factors of the PFF. This approach can help to select the most beneficial treatment technique prior to actual planning. © 2005, American Association of Physicists in Medicine. All rights reserved.