Risk factors of grade ≥ 2 radiation pneumonitis after gemcitabine induction chemotherapy for patients with non-small cell lung cancer

OBJECTIVES: To observe the risk factors affecting the occurrence of RP after gemcitabine-based induction chemotherapy. METHODS: Between January 2010 and December 2017, patients with NSCLC received gemcitabine or docetaxel chemotherapy, followed by radiotherapy at Zhejiang cancer hospital were enrolled in this study. Patients were treated with gemcitabine or docetaxel induction chemotherapy, followed by radiotherapy or concurrent chemoradiotherapy. Acute radiation pneumonitis was scored post chemoradiotherapy. RESULTS: One hundred and eighty-four patients with NSCLC were included in the gemcitabine group and 144 in the docetaxel group. The gemcitabine group experienced a higher incidence of grade ≥ 2 RP, compared with docetaxel group (25.5% Vs. 13.2%, P = 0.005). The optimal cutoff values of lung V(5), V(20), V(30) and MLD were set at 44% (AUC [area under the curve] = 0.593), 24% (AUC = 0.607), 14.2% (AUC = 0.622) and 1226 cGy (AUC = 0.626). On multivariate analysis, only lung V(30) was identified as a predictor for grade ≥ 2 RP (P = 0.03). The grade ≥ 2 RP rate was only 9.4% for the low-risk group (Lung V(5) ≤ 44%, V(20) ≤ 24%, V(30) ≤ 14.2%, and MLD ≤ 1226 cGy) in patients received gemcitabine induction chemotherapy. CONCLUSIONS: Gemcitabine chemotherapy before thoracic radiotherapy in NSCLC patients was related to a higher incidence of grade ≥ 2 RP, compared with docetaxel chemotherapy. The Lung dose-volume variable V(30) was the best predictor of grade ≥ 2 RP.