Comparison of long-term outcomes between esophagectomy and chemoradiotherapy after endoscopic resection of submucosal esophageal squamous cell carcinoma

Esophagectomy represents the standard treatment strategy for superficial esophageal cancer diagnosed pathologically as submucosal disease (pT1b) following an endoscopic resection (ER). However, chemoradiotherapy (CRT) is expected to become an alternative treatment option. This study retrospectively compared the outcomes of patients who underwent ER of submucosal esophageal squamous cell carcinoma, and who received additional treatment in the form of surgery and CRT. Data were collected from 83 patients who underwent ER and were diagnosed as pT1b (sm) between January 2002 and December 2013. Of them, 52 patients underwent additional treatment (19 surgery, 33 CRT). The long-term outcomes, recurrent patterns, and recurrence risk factor were analyzed retrospectively. No significant differences were identified between the two groups regarding the following aspects: sex, Charlson comorbidity index, tumor size, macroscopic type, cut end positivity, and en bloc resection rate. On the contrary, significant differences were observed in age (P = 0.042) and lymphovascular invasion (P = 0.003) between the two groups. There were more patients with positive lymphovascular invasion, which was one of the strongest risk factors, in the surgery group. The 3-year overall survival (OS) and relapse-free survival (RFS) rates were both 100% in the surgery group and 90.4% and 87.4%, respectively, in the CRT group. The 5-year OS and RFS rates both decreased to 89.5% in the surgery group and to 80.3% and 70.4%, respectively, in the CRT group. The surgery group achieved a superior OS and RFS compared to the CRT group, though not significant (P = 0.172, P = 0.127). Tumor recurrence was observed in 6 patients. All these patients were in the CRT group (P = 0.075). They included 3 patients with hematogenous metastases (of the lung, bone, and adrenal gland) and 3 patients with regional lymph node metastasis. The patient with hematogenous adrenal gland metastasis had simultaneous extended lymph node metastasis. Through a univariate analysis, it was observed that tumor size (≥ 40 mm) and positive lymphatic invasion represented the significant risk factors for recurrence in the CRT group (P = 0.048 and P = 0.035, respectively). To achieve a better long-term survival, surgery is recommended as the additional treatment for ER-pT1b esophageal cancer. While CRT represents an acceptable alternative, the indication should be carefully decided, especially in high-risk patients for recurrence with large tumor size (≥ 40 mm) or positive lymphatic invasion.