Effectiveness of image‐guided radiotherapy for locally advanced lung cancer patients treated with definitive concurrent chemoradiotherapy

BACKGROUND: Image‐guided radiotherapy (IGRT) is an advanced radiotherapy technique to improve the precision and accuracy of treatment delivery. A recent randomized controlled trial (RCT) for prostate cancer patients treated with radiotherapy via either IGRT or routine care reported statistically significantly worse overall survival (OS) for those patients treated with IGRT. This raised the concern regarding the effectiveness of IGRT in definitive concurrent chemoradiotherapy (dCCRT) for locally advanced lung cancer (LALC). METHODS: Eligible LALC patients diagnosed between 2011 and 2016 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratio (HR) of death and other outcomes were compared between IGRT and non‐IGRT. We also evaluated OS in various subgroups. RESULTS: Our primary analysis consisted of 797 patients in whom covariates were well balanced after PS weighing. The HR for death when IGRT was compared with non‐IGRT was 0.96 (95% confidence interval 0.79–1.15, P = 0.65). There were also no significant differences for most of the other outcomes or subgroup analyses. CONCLUSIONS: In this updated nonrandomized study, we found that OS of LALC patients treated with dCCRT was not statistically different between those treated with IGRT versus non‐IGRT. The results should be interpreted with caution given the nonrandomized design. Studies regarding toxicity, local control, or designed as RCT are needed to clarify the role of IGRT. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: The OS of LALC patients treated with dCCRT was not statistically different between those treated with IGRT versus those without IGRT, although the observed HR for death was less than unity (ie, in favor of IGRT). WHAT THIS STUDY ADDS: In this updated nonrandomized study using real world data with additional potential confounders, our study provided a reasonable tentative evidence in the lack of RCT as suggested in the literature.