- Histopathology was carcinoma - The patient was assigned to take 18F-FDG PET / CT for staging 8 - Patient agreement Exclusion criteria: - Typical distant metastatic lesions on conventional imaging or confirmed by histopathology - Prior chemotherapy or radiation therapy - Serious comorbidity or combined infectious disease - Pregnant or lactating women 2.1.2 Patient selection for chemoradiotherapy (objective 2) Inclusion criteria: - Met the eligible criteria of objective 1 - Stage II-III according to AJCC 7 - Age from 18 to 75 - ECOG 0 - 2 - Organ and bone marrow function that allows chemotherapy and radiotherapy Exclusion criteria: - Synchronous cancer - Tumor stage T4b - Abdominal lymph node metastasis - Contrast drug allergy - Patients who did not receive adequate radiation dose or tolerate < 50% of chemotherapy cycles - Failure to follow-up 2.2 METHODS 2.2.1 Study design A prospective cross-sectional descriptive study.