Severe acute radiation pneumonitis after concurrent chemoradiotherapy in non-small cell lung cancer

Objective: The study is to investigate the predictive values of dosimetric parameters and patient related factors in severe acute radiation pneumonitis (SARP) after concurrent chemoradiotherapy in non-small cell lung cancer (NSCLC). Methods: In all, 147 NSCLC patients treated with concurrent chemotherapy and 3DCRT between 2006 and 2010 was collected. Independent sample t test was used to compare parameter values between patients with SARP and those without SARP. Logistic regression was used to identify significant determined factor. Predictive value of each parameter was tested by ROC analysis. Pearson correlation was used to analyze correlations between parameters. Represent factors were identified by factor analysis. Results: The incidence of SARP was 9.5% (14/147). The means lung dose (MLD), V20, V30, V40, and V50 (χ2 =4.87 -6.84, P =0.009 -0.025, respectively) were determining factors for SARP. Our datasets shows that for SARP <5%, MLD, V20, V30, V40 and V50 should be ≤16.77 Gy, V20 ≤34.15%,. V30 ≤23.62%,. V40 ≤ 18.57%, V50 ≤ 13.02%. ROC analysis show that areas under MLD, V20, V30, V40 and V50 curves was corresponding to 0.678, 0.661, 0.667, 0.677, and 0.651, respectively. In addition, the sensitivity and specificity of each parameter at cutoff values are: 78.0% and 48.1% for MLD; 42.9% and 82.0% for V20; 78.6% and 52.9% for V30; 71.4% and 61.7% for V40, and 57.1% and 67.7% for V50. Factor analysis suggest that we can choose 1 or 2 parameters from MLD, V20, or V30, and another from V40 or V50 for predicting. The incidence of SARP was greater in patients with tumors in right lower lung than other locations (22.2% vs 6.7%, χ2 =6.19, P =0.023). Conclusions: The MLD, V20, V30, V40 and V50 are determining factors for SARP. As predictive value of each parameter alone is relatively week, using two or more parameters to predict SARP is recommended. (authors)