Analysis of relationship between severe radiation pneumonitis and dose-volume histogram parameters for non-small cell lung cancer treated with three-dimensional conformal radiation therapy

Abstract

Objective To explore the relationship between severe(≥grade 3 ) radiation pneumonitis (RP) and dose-volume histogram (DVH) parameters for non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3-DCRT). Methods Ninety-four patients with NSCLC treated with 3-DCRT were retrospectively analyzed. Clinical parameters were analyzed. DVH parameters analyzed were V20, V30, V40,mean lung dose (MLD),normal tissue complication probability(NTCP) ,and total dose. Results Age,sex, Karnofsky scored, performance status, forced expiratory volume in 1 second,presence of weight loss, preexisting lung disease, history of thoracic surgery, and history of chemotherapy were not associated with the risk of severe RP(P>0.05). However,in univariate analyses, V20, V30, V40, MID and NTCP were associated with severe RP(P 20 Gy,it was 0 when V30 35%. Conclusion MLD and V30 are significant predictive factors for severe RP and they should be limited to ≤20 Gy and ≤ 35% in order to reduce severe RP. Key words: Carcinoma, non-small cell lung; Radio therapy dosage; Radiation pneumonitis; Dose-volume histogram