Application of a radiation pneumonitis prediction model in patients with locally advanced lung squamous cell cancer.

BACKGROUND:The aim of the present study was to establish a new prediction model for radiation pneumonitis (RP) in locally advanced non-small cell lung cancer (LA-NSCLC) patients before and after radiotherapy. METHODS:The study involved 153 patients. Age, arterial partial oxygen pressure (PO2), forced vital capacity, pulmonary emphysema (PE), subclinical interstitial lung disease (sILD), and dosimetric parameters, such as mean lung dose and percentage of lung volume, and a dose >5/20 Gy (V5/V20), were considered candidate RP predictors. RESULTS:Of the 153 eligible patients, 33 (21.6%) developed RP, 68 had PE (43.8%), and 24 (15.7%) had sILD. Grades 2, 3, and 5 RP were scored in 17 (11.1%), 15 (9.8%), and 1 (0.7%) patient/s, Grade 4 RP was not observed. Grades 1, 2, and 3 PE were scored in 45 (29.4%), 22 (14.4%), and 1 (0.7%) patient/s. Grades 0 and 1 sILD were observed in 129 (84.3%) and 24 (15.7%) patients. Univariate analysis found age, PE, and sILD to be significantly correlated with grade ≥2 RP. Multivariate analysis revealed age >68 years, PE grade >1, and sILD grade ≥1 as independent risk factor for grade ≥2 RP in LA-NSCLC with squamous cell carcinoma (SCC). Finally, a new predictive risk score (PRS) comprised of these factors was developed. The PRS score was 0, 3-5, and 6-11 when the cumulative incidence of grade ≥2 RP was 8.8% (5 patients), 13% (3 patients), and 84.6% (13 patients) (P=<0.001). CONCLUSIONS:Age, PE, and sILD could independently and significantly predict RP in LA-NSCLC with SCC.