Intensity-Modulated Radiation Therapy May Improve Local-Regional Tumor Control for Locally Advanced Non-Small Cell Lung Cancer Compared With Three-Dimensional Conformal Radiation Therapy.

Abstract

Consistent results are lacking as regards the comparative effectiveness of intensity-modulated radiotherapy (IMRT) versus three-dimensional conformal radiotherapy (3DCRT) in patients with locally advanced non-small cell lung cancer (LA-NSCLC). Patients treated with definitive radiotherapy (RT) between 2002 and 2010 were retrospectively reviewed. Overall survival (OS), local-regional progression-free survival (LRPFS), distant metastasis-free survival (DMFS), and progression-free survival (PFS) were compared among patients irradiated with different techniques. The association between RT technique and survival indexes was assessed in a Cox proportional hazard regression model. Propensity score matching (PSM) was used to balance known confounding factors. A total of 652 patients were eligible for analysis, including 206 with 3DCRT and 446 with IMRT. The median OS of the 3DCRT and IMRT groups were 19.4 and 23.3 months, with the 5-year rate of 13% and 19%, respectively (p = .043). Multivariate analysis identified IMRT as an independent favorable factor associated with LRPFS and DMFS. PSM analysis further verified the beneficial effect of IMRT on LRPFS. No difference in OS or PFS was observed between the two techniques. Subgroup analysis revealed that IMRT might be differentially more effective in both OS and LRPFS among patients who were female, nonsmokers, with adenocarcinoma, or without weight loss. There was a significant reduction of lung toxicity and similar esophagus toxicity in the IMRT group when compared with the 3DCRT group. IMRT may confer superior LRPFS and comparable OS than can be achieved with 3DCRT in LA-NSCLC, along with the reduction of pulmonary toxicity. Based on the largest number of patients from a single institution, the present study demonstrated that intensity-modulated radiotherapy (IMRT) could provide superior local-regional progression-free survival and similar overall survival compared with the traditional three-dimensional conformal radiotherapy (3DCRT) for stage III non-small cell lung cancer (NSCLC). IMRT was also found to be associated with the significantly decreased incidence of pulmonary toxicity. These results suggest that IMRT should be considered a surrogate for 3DCRT in locally advanced NSCLC and might be the preferred option for a female nonsmoker with adenocarcinoma and a potentially high risk of pulmonary toxicity from radiotherapy.