The Impact of Radiotherapy Dose in Patients with Locally Advanced Esophageal Squamous Cell Carcinoma Receiving Preoperative Chemoradiotherapy

Objective: For patients with esophageal squamous cell carcinoma, preoperative chemoradiotherapy followed by planned esophagectomy is used as a curative treatment modality. However, the impact of radiotherapy dose remains undefined. Method: A total of 141 patients with stage III esophageal squamous cell carcinoma (ESCC; as defined by the 7th American Joint Committee on Cancer), receiving preoperative chemoradiotherapy followed by esophagectomy between 2000 and 2015 at Kaohsiung Chang Gung Memorial Hospital, Taiwan, were retrospectively reviewed. The radiotherapy dose of preoperative chemoradiotherapy (36 Gy before 2009 and 50–50.4 Gy after 2009) and other clinicopathological parameters were collected and correlated with the response to chemoradiotherapy and treatment outcome. Result: Of these 141 patients, the radiotherapy dose was 36 Gy in 59 (42%) patients and 50 Gy in 82 (58%) patients. A complete pathological response was noted in 12 (20%) of 59 patients receiving 36 Gy radiotherapy, and 37 (45%) of 82 patients receiving 50 Gy radiotherapy (p = 0.002). The three-year overall survival and disease-free survival rates were 31% and 25% in patients receiving 36 Gy radiotherapy, and 54% and 46% in patients receiving 50–50.4 Gy radiotherapy, respectively (p = 0.023 for overall survival; p = 0.047 for disease-free survival). Multivariate analysis showed that a higher radiotherapy dose was associated with increased pathological complete response (p = 0.003, hazard ratio: 3.215), better overall survival (p = 0.024, hazard ratio: 1.585), and superior disease-free survival (p = 0.049, hazard ratio: 1.493). However, higher radiotherapy doses revealed more surgical complications, including acute respiratory distress syndrome (p = 0.048) and anastomosis leaks (p = 0.004). Conclusion: For patients with locally advanced ESCC, preoperative chemoradiotherapy with higher radiotherapy doses led to increased pathologic complete response rates and improved survival.