Outcome and toxicity of intensity modulated radiotherapy with simultaneous integrated boost in locally advanced non-small cell lung cancer patients.

Abstract

The aim of this study was to assess the feasibility and treatment outcome of intensity modulated radiation therapy with simultaneous integrated boost (SIB-IMRT) in locally advanced non-small cell lung cancer (NSCLC) patients. A total of 64 NSCLC patients with stage IIB (3%), IIIA (36%), and IIIB (61%) were treated with concomitant (N=47; 73%) or sequential (N=9; 14%) chemotherapy between February 2009 and January 2014. Eight patients (13%) received RT alone. All patients received the same irradiation scheme using IMRT: prophylactic dose for mediastinum was 56Gy at 1.65Gy/fraction and SIB to macroscopic disease up to 68Gy at 2Gy/fraction. The median follow-up was 16months (range, 1-70months). The overall survival rate for all patients was 79% after 1year and 46% after 2years. Disease-free survival (DFS) was 81 and 45% after 1 and 2years, respectively, resulting in a median DFS of 16months. Multivariate analysis showed a statistically significant association between stage IIIB patients and a higher risk of mortality (HR 2.11; P=0.019). In addition, T4 stage associated with higher risk of recurrence (HR 2.23; P=0.024) while concomitant chemoradiation was associated with lower risk of any recurrence (HR 0.34; P=0.004) No patient experienced grade≥3 esophagitis and only 6 cases (9%) had grade 3 pneumonitis. Only having a higher lung volume was associated with higher risk of pneumonitis in the multivariate analysis (HR 16.21; P=0.022). This study in advanced NSCLC patients shows that SIB-IMRT is an effective technique with acceptable toxicity, also when combined with chemotherapy.