Therapeutic effects of intensity-modulated radiotherapy and three-dimensional conformal radiotherapy in patients with stage III N (+ ) esophageal cancer: a comparative study

Abstract

Objective To investigate the therapeutic effects and adverse effects of three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) in patients with stage Ⅲ N (+ ) esophageal cancer. Methods A total of 428 patients with esophageal cancer who were treated from 2003 to 2012 and met the inclusion criteria were enrolled, and among these patients, 293 received 3DCRT and 135 received IMRT. The median radiation dose was 60 Gy. The Kaplan-Meier method was used to calculate survival rates and the log-rank test was used for survival difference analysis. Results The 1-, 3-, and 5-year local control rates in 3DCRT group and IMRT group were 65.1%/40.6%/37.5% and 70.0%/57.0%/49.4%, respectively (P=0.025). The 1-, 3-, and 5-year overall survival (OS) rates in 3DCRT group and IMRT group were 56.0%/22.3%/15.7% and 53.3%/29.2%/17.8%, respectively (P=0.394). Compared with the 3DCRT group, the IMRT group had a significantly higher mean lung dose (P=0.001) and significantly lower lung V20, V25, V30, and V35(P=0.007, 0.000, 0.000, and 0.000). Compared with the 3DCRT group, the IMRT group had significantly higher incidence rates of grade Ⅱ and Ⅲ acute radiation esophagitis and grade Ⅱ acute radiation pneumonitis (P=0.000, 0.006, and 0.043). Of all patients, 343 patients died, and the main cause of death was local factors (60.6%), followed by distant metastasis (25.1%). The IMRT group had a significantly lower proportion of patients who died of local factors than the 3DCRT group (51.0% vs. 64.5%, P=0.021). Conclusions IMRT is effective in the treatment of esophageal cancer, and compared with 3DCRT, it significantly improves the local control rate. However, IMRT does not improve the long-term OS rate. The main cause of death is local factors, followed by distant metastasis. The patients receiving IMRT have a significantly lower proportion of those who die of local factors than the patients receiving 3DCRT. Key words: Esophageal neoplasms/radiotherapy; Radiotherapy, three-dimensional conformal; Radiotherapy, intensity-modulated; Prognosis