Jingbo Wang¹, Jianzhong Cao², Zhe Ji², Lipin Liu², Wei Jiang², Yu Men², Cai Xu², Luhu Wang², Jingbo Wang²

 ¹Dept. Radiation Oncology, Cancer Hospital, Chinese Academy of Medical Sciences, ²Chinese Academy of Medical Sciences, Cancer Hospital

Objective:Currently IMity-modulated radiotherapy (IMRT) is regarded as a promising but unproven therapy for locally advanced non-small cell lung cancer (LA-NSCLC). This study aimed to evaluate the impact of introducing IMRT in LA-NSCLC based on patients receiving definitive radiotherapy (RT) throughout an 11-year span from an academic cancer center. Method:Patients treated with definitive RT  (≥ 50 Gy) between 2000 and 2010 were divided into three eras according to availability of IMRT: 2000 to 2003 (period A, no IMRT, IMRT rate 0%), 2004 to 2006 (period B, introduction of IMRT, IMRT rate 3.5%) and 2007 to 2010 (period C, full access to IMRT, IMRT rate 85.6%). Patients' characteristics, treatment modality, survival and treatment related toxicities were compared between 3 periods. Result: A total of 946 patients were analyzed. Less smokers, more stage IIIA diseases and more patients receiving concurrent chemo-radiotherapy (CRT) were observed in period C. The median overall survival (OS), local-regional progression free survival (LRPFS), distant metastasis free survival (DMFS) and progression free survival (PFS) for the whole population, period A, B and C were 19.8 vs. 16.6 vs. 18.2 vs. 23.3 moths, 22.1 vs. 16.2 vs. 18.7 vs. 40.5 months, 20.7 vs. 17.1 vs. 17.0 vs. 33.1 months and 11.4 vs. 10.8 vs. 11.3 vs.11.9 months, respectively. Accordingly, the 5-y OS, LRPFS, DMFS and PFS were 14.3% vs. 9.8% vs. 12.0% vs. 18.3%, 34.3% vs. 22.9% vs. 28.4% vs. 43.6%, 32.2%vs. 25.2% vs. 23.6% vs. 40.5% and 14.2% vs. 10.7% vs. 11.1% vs. 18.0%, respectively. All survival indexes significantly increased in period C. Multivariate analyses identified IMRT as the independently favorable indicators for all survival indexes. The incidence of radiation induced lung toxicity (RILT) significantly decreased in period C (32.2% vs. 24.9% vs. 12.8%, P<0.001) whereas that of radiation induced esophagus toxicity (RIET) remained stable (29.4% vs.39.0% vs. 33.1%,  P=0.064) throughout the overall study period. Conclusion: IMRT was associated with improved tumor control, prolonged survival and decreased RILT, independent of treatment modality and radiation dose.

Key Words: Locally advanced Non-small cell lung cancer  IMRT