Choice of radiotherapy planning modality influences toxicity in the treatment of locally advanced esophageal cancer

Purpose: Three-dimensional computed tomography-based radiotherapy planning (3DCTP) is increasingly employed in the treatment of esophageal cancer. It is unknown whether a 3DCTP approach influences outcomes compared to two-dimensional planning (2DP). This study compares clinical outcomes for homogenously treated patient cohorts stratified by planning modality. Methods and Materials: A retrospective chart review was conducted on patients with T3/4 and/or node-positive esophageal carcinoma treated at the Cleveland Clinic between July 1, 2003 and May 31, 2006 who were managed with an institutional regimen consisting of preoperative radiotherapy, whether 3DCTP or 2DP [30 Gy/20 fractions/1.5 Gy twice daily over 2 weeks], with concurrent cisplatin and 5-fluorouracil the first week. Following definitive resection, an identical postoperative course of concurrent chemoradiotherapy (CRT) was delivered. Results: One hundred and forty-one patients completed preoperative CRT and were available for review. The median follow-up of living patients is 21.7 months. Fifty-five percent underwent 3DCTP and 45% had 2DP. The treatment groups were similar, with the exception of clinical stage group, with 2DP having more stage II and fewer stage III patients than 3DCTP (p=0.02). 3DCTP plans had significantly smaller field sizes by area (p<0.0001). Pathologic response, locoregional control, distant control, and overall survival were equivalent between the two planning modalities. Esophagitis was significantly less common with a 3D approach compared to 2D planning (49% vs. 71%, p=0.0096), with other toxicities equivalent between the groups. Conclusions: 3DCTP reduces acute esophagitis in patients receiving multimodality therapy for esophageal cancer without compromising clinical outcomes.