Effect of adjuvant radiotherapy after endoscopic resection of early esophagus cancer to prevent new intraluminal mucosal recurrence.

381 Background: Endoscopic resection (ER) is effective for treating T1a early esophageal squamous cell carcinoma (ESCC). Occasional distant metastasis and recurrence are inevitable invasion in depth of muscularis mucosa(MM). Additional surgical resection is an effective means for cure and prevent recurrence, but it imposes a heavy physical burden. Chemoradiation therapy (CRT) is a comparable alternative to surgery. Not all patients will want those additional treatment. Another problem is the occurrence of new esophagus intraluminal mucosal recurrence. After endoscopic treatment, there is an increased risk of scarring and deformity. But there are few reports of the effectiveness of additional RT in suppressing new lesions. This study was designed to verify the efficacy of not only curability but also suppressive effect the occurrence of new lesions additional treatment of T1a(MM) ESCC. Methods: This study was a retrospective study. We reviewed 71 consecutive patients who underwent ER followed by clinical stage I (T1a: MM) ESCC. We compared patients in the radiotherapy group or non-radiotherapy group after ER. Patients of radiotherapy group received radiation within 3 months after ER. All patients underwent regular follow-up. Recurrence, recurrence-free survival, cancer-specific survival, overall survival, and complications were evaluated. Results: There were 34 cases of radiotherapy group and 37 cases of non-radiotherapy group. 3 patients (8.9 %) in the radiotherapy group experienced intraluminal mucosal recurrence, and 2 patients (6.6 %) experienced local recurrence. On the other hand, in the non-radiotherapy group, 9 patients (24.3 %) experienced intraluminal mucosal recurrence, and 7 patients (18.9 %) experienced local recurrence (intraluminal mucosal recurrence: p< 0.05, local recurrence p=0.14). The recurrent group received chemotherapy. The 3-year cumulative recurrence-free survival was 97 % in the radiotherapy group and 83.7 % in the non-radiotherapy group (p< 0.05). No severe radiation toxicities were recorded. Conclusions: The radiotherapy after ESD reduced the risk of lymph nodes recurrence not only local lymph node recurrence but also new intraluminal mucosal recurrence, and safe and effective therapeutic strategy.