Propensity score-based comparison of survival and radiation pneumonitis after definitive chemoradiation for esophageal cancer: Intensity-modulated radiotherapy versus three-dimensional conformal radiotherapy

Abstract

PurposeTo compare survival outcomes and radiation pneumonitis (RP) between intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) in patients with esophageal cancer (EC) who underwent definitive chemoradiation therapy (CRT). MethodsClinical characteristics and dose-volume histogram parameters were collected for 388 EC patients who received definitive CRT with either IMRT (n = 297) or 3DCRT (n = 91) from 2010 through 2017. Dosimetric parameters, survival end-points, and symptomatic RP (grade ≥2) were compared between groups. Propensity score matching (PSM) was performed to balance potential confounding factors. Univariate and multivariate logistic regression analyses were applied to identify predictors of RP. ResultsCompared with 3DCRT, IMRT was significantly associated with better overall survival (OS; P = 0.001), progression-free survival (PFS; P = 0.008), and distant metastasis-free survival (P = 0.011), but not with locoregional failure-free survival (P = 0.721). Moreover, IMRT demonstrated a remarkably lower risk of RP than 3DCRT (5.4% vs 23.1%, P < 0.001). PSM analysis further confirmed the clinical benefit of IMRT. In the matched cohort, radiation modality was independently correlated with OS and PFS. On multivariate analysis, smoking history (odds ratio [OR]: 4.225, P = 0.002), primary tumor length (OR: 2.764, P = 0.049), radiation modality (OR: 10.760, P < 0.001), planning target volume (OR: 1.004, P < 0.001), and lung V20 (OR: 1.286, P = 0.002) were found to be significant predictors of RP. ConclusionsCompared with 3DCRT, IMRT was associated with more favorable survival and a reduced risk of RP after definitive CRT, supporting the routine use of IMRT for EC.