This is a single-arm prospective phase II clinical trial to investigate the efficacy and safety of adjuvant concurrent chemoradiotherapy with simultaneous integrated boost following hepatectomy for intrahepatic cholangiocarcinoma with narrow margin (<1cm) or nodal involvement. Eligibility patients will receive IMRT or VMAT. The prescription dose to high-risk area of tumor bed or positive lymph node was planned at 55-60Gy and the prescription dose to lymphatic drainage regions was planned at 40-45Gy in 20-25 fractions. During radiotherapy, patients will concurrently receive capecitabine (1600 mg/m² on days 1-14, every 21 days for 2 cycles). After radiotherapy, maintenance therapy with capecitabine will continue (2000 mg/m² on days 1-14, every 21 days for 6 cycles). For patients who cannot tolerate capecitabine, S-1 will be used as an alternative. The primary endpoint is 2-year recurrence-free survival. The secondary endpoints are 2-year overall survival, local-regional control rate and incidence of grade 3 or higher adverse events.

Inclusion Criteria:

• Age > 18 years, < 80 years

• Patients with primary surgical treatment

• Postoperative pathology confirmed intrahepatic cholangiocarcinoma

• Postoperative pathology showing narrow resection margin (<1cm) or positive lymph nodes

• R0/R1 resection

• Postoperative Child-Pugh score A5-B7

• Patients meeting either of the following conditions must undergo preoperative or pre-radiotherapy PET-CT to exclude distant metastasis or lymph node metastasis beyond the region from the lower esophagus to the aortic bifurcation

  1. Lymph node metastasis accounting for >50% of dissected nodes
  2. Lymph node metastasis involving the paracardial region or below the renal vein level

• Postoperative contrast-enhanced liver MRI to exclude Intrahepatic satellite nodules

• Recovery from surgery with Eastern Cooperative Oncology Group performance status score of 0-2

• Estimated life expectancy >3 months

Exclusion Criteria:

• History of malignancies, except for basal cell skin carcinoma and in situ carcinoma of the cervix
• Had prior abdominal irradiation
• Had prior liver transplantation
• Had serious myocardial disease or renal failure
• Had moderate or severe ascites with obvious symptoms 4 months after surgery
• Duration from surgery ≥ 4 months