Long-Term Clinical Outcome and Safety Analysis of Superficial Esophageal Cancer Patients Receiving Definite or Adjuvant/Salvage Radiotherapy.

PURPOSE/OBJECTIVE(S) The role of definite concurrent chemoradiation (CCRT) or adjuvant/ salvage radiation therapy (RT) in the treatment of superficial esophageal cancer remains uncertain. We hypothesize that definite or adjuvant/salvage RT/CCRT was an alternative treatment for superficial esophageal cancer, especially for those who are ineligible for endoscopic resection (ER) or those with T1b tumor or receiving non-curative endoscopic resection. We aim to investigate the long-term clinical outcome and safety of superficial esophageal cancer patients receiving definite or adjuvant/salvage radiotherapy. MATERIALS/METHODS 48 patients with clinical T1N0M0 esophageal squamous cell carcinoma from 2011 to 2019 were included. 33 patients received RT (n = 9)/CCRT (n = 24). 15 patients received ER+RT (n = 8)/CCRT (n = 7). In ER+RT/CCRT group, median dose of 50.40 Gy and 59.36 Gy were delivered to regional lymph nodes and primary tumor with recurrence or tumor bed with positive margin, respectively. In RT/CCRT group, median dose of 50.40 Gy and 59.36 Gy were delivered to regional lymph nodes and primary tumor, respectively. 31 patients (64.5%) received concurrent chemotherapy. The Kaplan-Meier curves were used to calculate actuarial rates of 1-, 3-, and 5-year local recurrence-free survival (LRFS) and overall survival (OS). RESULTS The median follow-up time was 38.5 months. The OS at 1-, 3-, and 5-year was 95.8%, 90.9% and 90.9%, respectively. The LRFS at 1-, 3-, and 5-year was 97.9%, 95.2% and 95.2%, respectively. The 5-year LRFS and OS in ER + RT/CCRT group were 100.0% and 100.0%, respectively. 5-year LRFS and OS in RT/CCRT group was 92.7% and 86.3%, respectively. Local recurrence occurred in 2 patients (4.2%) within the radiation field in the RT/CCRT group. No salvage therapy was delivered to these 2 patients and their median OS was 27.2 months and 13.0 months, respectively. No distant metastasis or regional recurrence were observed in all 48 patients. The cause of death included local recurrence in 2 patients and infectious pneumonia in 2 patients. The most frequent early toxicity was esophagitis. Grade 1-2 esophagitis in 13 (86.6%) and 29 (87.8%) patients in the ER+RT/CCRT and RT/CCRT group, respectively. Grade 3 in 1 (6.6%) and in 1 (3.0%) patient in the ER+RT/CCRT and RT/CCRT group, respectively. The most frequent late toxicity was esophageal stricture. Grade 1-2 occurred in 12 (80%) and 32 (96.9%) patients in the ER+RT/CCRT and RT/CCRT group, respectively. Grade 3 esophageal stricture occurred in 3 (20%) patients and 1 (3.0%) patient in the ER+RT/CCRT and RT/CCRT group, respectively. No patients experienced grade 4 toxicity and there was no treatment-related death. CONCLUSION Our long-term results of definite or adjuvant/salvage radiotherapy for patients with superficial esophageal cancer showed favorable outcomes and acceptable toxicities. Radiotherapy was an alternative treatment for superficial esophageal cancer.