Comparison of the Efficacy and Toxicities for Locally Advanced Non-Small Cell Lung Cancer Treated By Simultaneous Integrated Boost Intensity-Modulated Radiotherapy or Conventional Intensity-Modulated Radiotherapy: A Retrospective Study of 426 Patients

Abstract

Consistent results are lacking about the effectiveness and safety of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) versus conventional intensity-modulated radiotherapy for locally advanced non-small-cell lung cancer (LA-NSCLC). Therefore, we conducted a retrospective analysis to demonstrate the role of SIB-IMRT for patients. Patients that had histologically confirmed NSCLC，stage III disease and received thoracic IMRT from January 2014 to December 2016 were respectively reviewed. Patients treated with SIB-IMRT were identified in the study. The outcome, toxicities and dose to organs at risk (OARs) were compared between the groups of SIB-IMRT and conventional IMRT using statistical methods. A total of 426 patients with stage III NSCLC were included in the study, including 128 patients with SIB-IMRT and 298 patients with conventional IMRT. Median follow-up of surviving patients was 25 months. For the patients treated with conventional IMRT, the median dose to the PTV was 60Gy/2Gy/30f. As for the patients with SIB-IMRT, the median dose to the PGTV was 59.92Gy/2.14Gy/28f, and the median dose to the PTV was 50.4Gy/1.8Gy/28f. SIB-IMRT group had more stage IIIB disease (69.5% vs. 53%，P=0.002), a larger PTV volume (median: 504ml vs. 402ml，P＜0.001), and a larger PTV/lung volume ratio (median, 0.18 vs. 0.12, P＜0.001). The median OS of the SIB-IMRT and conventional IMRT groups were 34.5 and 31.7 months, with the 2-year rates of 60.4% and 59%, respectively (P=0.797). No significant difference was observed between the two groups regarding the PFS (32.1% vs. 38.7%, P=0.415)，LRFS (57% vs. 66.3%, P=0.39), and DMFS (54.8% vs. 57.8%, P=0.494) at 2 years, respectively. The maximum dose of esophageal for SIB-IMRT is lower comparing with conventional IMRT (Median 63.28Gy vs. 64.86Gy，P=0.021). No significant difference was observed between the two groups regarding the toxicities such as radiation pneumonitis, esophagitis, hematologic toxicities and gastrointestinal reactions. The present study consisted of the largest number of patients from a single institution, demonstrating that SIB-IMRT might be an effective and safe option for patients with locally advanced NSCLC, especially for those with large mass or wide lymph node metastasis. Prospective randomized studies are warranted.