Long term survival analysis of middle and lower thoracic esophageal carcinoma of stage T4N (+ ) treated with 3DRT

Abstract

Objective To observe the long-term survival and adverse reactions in patients with stage T4N (+ ) Ⅲ middle and lower thoracic esophageal carcinoma undergoing intensity-modulated radiotherapy (IMRT). Methods From 2004 to 2010, 300 patients with stage T4N (+ ) Ⅲ middle and lower thoracic esophageal carcinoma, consisting of 202 treated with three-dimensional conformal radiotherapy (3DCRT) and 98 treated with IMRT, were enrolled as subjects. All patients received conventionally fractionated radiotherapy with a prescribed dose of 60 Gy. The long-term survival and adverse reactions were compared between patients treated with the two different radiotherapy regimens. The survival rates were calculated by the Kaplan-Meier method and analyzed by the log-rank test. Results The 5-and 7-year sample sizes were 239 and 120, respectively. The 3DCRT group had significantly lower 1-, 3-, 5-, and 7-year local control (LC) and overall survival (OS) rates than the IMRT group (64.4% vs. 68.3%, 40.6% vs. 55.3%, 38.3% vs. 51.9%, 34.2% vs. 51.9%, P=0.048; 54.5% vs. 63.3%, 19.8% vs. 34.7%, 14.7% vs. 24.4%, 10.9% vs. 20.3%, P=0.013). The stratified analysis showed that for patients older than 65 years, with the length of esophageal lesion>8.0 cm before radiotherapy, the largest diameter of esophageal lesion in computed tomography image>4.6 cm, gross tumor volume (GTV)>60 cm3, metastases to adjacent tissues or organs, stage N2, and without chemotherapy, the IMRT group had a significantly higher OS rate than the 3DCRT group (P=0.022, 0.003, 0.022, 0.034, 0.016, 0.044, 0.047). The GTVDmin and GTVD100 were significantly higher in the IMRT group than in the 3DCRT group (P=0.000, 0.000), while the Dmax of the spinal cord was significantly lower in the IMRT group than in the 3DCRT group (P=0.000). Compared with the 3DCRT group, the IMRT group had a significantly higher incidence of acute radiation-induced esophagitis, particularly grade 1-2 esophagitis (P=0.000). The mortality rate caused by local tumor was significantly higher in the 3DCRT group than in the IMRT group (P=0.039). Conclusions In the treatment of locally advanced middle and lower thoracic esophageal carcinoma, IMRT is safe and effective; it significantly improves the LC rate and long-term survival without severe toxicity to normal tissues. The results of this retrospective study need to be confirmed by prospective randomized controlled studies. Key words: Esophageal neoplasms/radiotherapy; Radiotherapy, three-dimensional; Radiotherapy, intensity-modulated; Prognosis