93P - The Clinical Characteristics of 50 Patients with Radiation Pneumonitis

Abstract

Aim: To analyse the risk factors and therapy modality which lead to radiation induced pneumonia (RP). Methods: We included the patients with lung cancer who were diagnosed RP after 3D-CRT or IMRT. The radiation doses respectively were 60-70 Gy in 30-35 fractions in NSCLC and 50-60 Gy in 25-30 fractions in SCLC. We divided the patients into 3 groups according to the grade of RP using RTOG standard to compare the risk factors of different grade through analysing the clinical character, therapy modalities, and dosiology. We also calculated DVH to statistic dosimetric parameters. SPSS16.0 software was used for statistical analysis. Results: With follow-up to June 2014, there were 50 cases who were diagnosed with RP more than grade 2. Among them, grade 2 was seen in 16 cases (32%), grade 3 in 22 cases (44%), grade 4 in 12 cases (24%). 46 cases were male and 4 females, age range was 40 to 72 years. According to AJCC 2009 staging system, there were 4, 36, and 10 cases in stage II, III and IV respectively. Among 48 patients with immune dysfunction, 76% of which were severe, 20% were mild-moderate. Among 46 patients receiving induction chemotherapy previously, 60.8% of patients received more than 3 cycles. 24% of patients received targeted therapy after or during radiotherapy, of which 67% showed grade 2 RP. In terms of time of damage occurring, 84% of patients were during 8 weeks and only 16% more than 8 weeks after radiotherapy. In a stratified analysis according to different grade of RP, there was no difference between three groups with respect to clinical characteristics, including age, sex, disease types, pathological types; but with respect to KPS, disease stage, and immune function after radiotherapy, there was a statistically significant difference between groups.There was statistical difference with respect to treatment dose, induced chemotherapy cycles, and combined targeted therapy. A higher proportion of patients with severe pneumonia were treated with more than 3 cyles of induced chemotherapy and combined with targeted therapy. Conclusions: The retrospective results of 50 cases with RP showed that cancer stage, poor physical condition and low immune function after radiotherapy is associated with high grade RP; multi-cycle induction chemotherapy, combined targeted therapy, bigger imaging effusion area and earlier occuring time of RP were the main influencing factors of severe RP. GTV size and double lung irradiated volume were still the main dosimetry indicators affecting the severity of RP. Disclosure: All authors have declared no conflicts of interest.