NTCP modelling of lung toxicity after SBRT comparing the universal survival curve and the linear quadratic model for fractionation correction

• DOI: 10.3109/0284186x.2010.543695
• Publication Date: 2011-01-04T11:37:41Z
• Authors: Berit M. Wennberg; Pia Baumann; Giovanna Gagliardi; Jan Nyman; Ninni Drugge; Morten Hoyer; Anders Traberg; Kristina Nilsson; Elisabeth Morhed; Lars Ekberg; Lena Wittgren; Jo-Åsmund Lund; Nina Levin; Christer Sederholm; Rolf Lewensohn; Ingmar Lax
• Keywords: Pneumonitis; Therapeutic index

Background. In SBRT of lung tumours no established relationship between dose-volume parameters and the incidence toxicity is found. The aim this study to compare LQ model universal survival curve (USC) calculate biologically equivalent doses in see if will improve knowledge on relationship. Material methods. Toxicity data radiation pneumonitis grade 2 or more (RP2+) from 57 patients were used, 10.5% diagnosed with RP2+. DVHs corrected for fractionation (LQ USC) analysed Lyman- Kutcher-Burman (LKB) model. LQ-correction α/β = 3 Gy was used USC were: Gy, D0 1.0 10, α 0.206 Gy−1 dT 5.8 Gy. order understand relative contribution different dose levels calculated NTCP concept fractional used. This might give an insight questions whether "high small volumes" "low large are most important toxicity. Results Discussion. analysis LKB-model using m 0.4, D50 30 resulted volume dependence parameter (n) correction n 0.87 0.71. Using 0.3, 20 0.93 0.83 correction. tumours, modelling comparing models (LQ,USC) correction, shows that low contribute less high when USC-model. Comparing breast cancer, cancer whole irradiation implies response treatment specific. More however needed have a reliable modelling.