Author’s Reply: Comparison of Outcomes Between Additional Esophagectomy After Noncurative Endoscopic Resection and Upfront Esophagectomy for T1N0 Esophageal Squamous Cell Carcinoma

Abstract

Dear Editor, First of all, we appreciate the letter from Dr. Zhichao and colleagues and their interest in our recent article. In this particular article, published in Annals of Surgical Oncology, we aimed to clarify the clinical features of additional esophagectomy for patients after noncurative endoscopic resection (ER) compared with upfront esophagectomy for T1N0 esophageal squamous cell carcinoma (ESCC). Dr. Zhichao and colleagues mentioned that the tumor histology characteristics, especially poor tumor differentiation and the presence of lymphovascular invasion, may differ for patients receiving esophagectomy between those treated with noncurative ER (ER group) and those treated with upfront esophagectomy (non-ER group). In our additional analysis, poor tumor differentiation was observed in 0 patients in the ER group (0%) and 21 (8.0%) patients in the non-ER group (p = 0.03). Lymphatic invasion was observed in 39 ER patients (68.4%) and 107 nonER patients (40.5%) (p\\0.001), and vascular invasion was observed in 39 ER patients (68.4%) and 107 non-ER patients (40.5%) (p = 0.26). Poor differentiation of ESCC can be diagnosed with the appearance of microvessels by a magnified endoscopy, and tumors with poorly differentiated components usually are treated by upfront surgery. Meanwhile, the existence of lymphovascular invasion is one of the major determinants of additional esophagectomy after non-curative ER. That is why the incidence of lymphovascular invasion was higher in the ER group than in the non-ER group. Also, Zhichao and colleagues pointed out selection bias and recommended matched analysis. We agree with the existence of selection bias in this study. The patients in the ER group had tumors clinically diagnosed as potentially curable by ER. In contrast, the patients in the non-ER group had tumors beyond the indication for ER. Therefore, matched analysis, such as propensity-score matching, may not compensate for the bias related to tumor-related variables. This study showed that the risk of lymph node metastasis was equivalent between the ER and non-ER groups. Besides, we demonstrated that the additional esophagectomy after noncurative ER provided excellent long-term outcomes despite the high incidence of lymph node metastasis. Zhichao and colleagues mentioned that it remains unclear how much additional esophagectomy contributes to the treatment of patients with noncurative ER because most of the patients were tumor-free. A consensus exists that surgery should be recommended for patients who underwent noncurative ER for gastrointestinal malignancies. Many authors also have reported that patients with ESCC who underwent noncurative ER should receive additional treatment. In our study, 20 patients in the ER group Society of Surgical Oncology 2021