Concurrent Chemoradiotherapy After Endoscopic Resection for Stage I Esophageal Carcinoma

Inclusion Criteria:

* Male or female patients aged 18 to 75 years (18 years and 75 years are inclusive).
* The Eastern Cooperative Oncology Group (ECOG) performance status score is 0 to 1 point.
* Weight loss (intentional or unintentional) of less than or equal to 10% of body weight in the 6 months prior to surgery.
* Complete radiological staging is required before ER, including gastroscopy, endoscopic ultrasonography, chest CT, brain MRI and bone scan (if positive, bone metastasis must be confirmed by MRI or CT examination of corresponding parts, otherwise bone metastasis cannot be determined). No lymph nodes with shorter diameter \>10mm in mediastinum presented by endoscopic ultrasonography or chest CT. No abdominal nor neck lymph node metastases presented by B-ultrasound.
* Primary lesion located in thoracic esophagus.
* Clinical stage: cT1（sm1/sm2）N0M0 (The 8th edition of American Joint Committee on Cancer \[AJCC\]) before ER.
* ER is a complete removal of tumor.
* Pathologically confirmed squamous cell carcinoma.
* Histologically confirmed diagnosis of T1a with LVI, T1b（sm1/sm2）with/without LVI, or microscopically positive vertical resection margin (R1 resection).
* Less than three endoscopically resected synchronous lesions with high risk factors (lymphovascular or mucous membrane invasion, submucous infiltration, poor differentiation or microscopically positive vertical resection margin), which can be safely encompassed in a tolerable radiation plan.
* Non-pregnancy and non-pregnancy plan in the next 12 months (urine pregnancy test or blood pregnancy test is required for women of childbearing age to exclude pregnancy).
* No serious medical disease nor organ dysfunction. Adequate BM, liver, kidney and heart function.
* Meet the treatment and follow-up criteria, able to receive treatment, follow-up and pathological examination. The subject has voluntarily signed the written informed consent form (ICF).

Exclusion Criteria:

* Any positive N or M stage.
* Macroscopic residual tumor (R2 resection).
* Lesions with poor prognistic factors (lymphovascular or mucous membrane invasion, submucous infiltration, poor differentiation or microscopically positive vertical resection margin) solely resected endoscopically more than six months before evaluation.
* Patients with other malignant tumors within 5 years before enrollment.
* Unavailable gastroscope due to esophageal stenosis.
* Previously received electrocoagulation, other treatments (including photodynamic therapy, multipolar electrocoagulation, argon plasma coagulation, laser therapy, et al.) or radiotherapy.
* Previously received any esophageal surgery, excluding fundoplication with no complications (no slippage, dysphagia, et al.).
* Uncontrolled coagulation disorders: INR \>2 or PLT\<75,000/μL.
* Patients who are taking or have taken (within 7 days before/after treatment) aspirin, clopidogrel or other non-steroidal anti-inflammatory drugs.
* Patients with history of uncontrolled drug or alcohol dependence that limits the ability to understand or comply with medical orders, including inability to understand and execute ICF, post-treatment orders, or follow-up guidelines.
* Patients implanted pacemakers, including AICD, nerve stimulator or cardiac pacemaker, without the permission from specialist in charge.
* Patients with mental disease, serious medical disease or major organ dysfunction.
* Pregnant, lactating women or women without offspring.
* Patients unable to understand/express informed or consent.
* Patients with known allergy to platinum compounds or paclitaxel.
* Other circumstances which are considered by the investigator that the subject is unsuitable to be enrolled