This is a single-arm prospective phase II clinical trial to investigate the efficacy and safety of adjuvant simultaneouslyintegrated boost radiotherapy following narrow-margin(<1cm) hepatectomy in patients with HCC. Eligibility patients will receive IMRT or VMAT to high risk area of tumor bed and tumor bed. The prescription dose to 95% GTVtb boost was planned at 55-60Gy, with PTV 45-50Gy, in 23-25 fractions, mainly depending on the dose constraints of OARs. The primary endpoint is the 3-year OS, the secondary endpoints are disease-free survival, patterns of failure, toxic events and local control rate.

Surgical resection is the primary treatment for HCC. However, it is associated with a high rate of recurrence and death. Based on the results of our retrospective study and phase II study, adjuvant radiotherapy is an effective, tolerable, and promising adjuvant regimen in patients with narrow-margin(<1cm) after hepatectomy. The 3-year and 5-year OS rates of 88.2% and 72.2% were significantly higher than the expected rates based on published reports and exceeded our predetermined threshold. However, there is no standard for the prescription dose. The high risk area of recurrence is mostly close to the blood vessels in the tumor bed, and simultaneously integrated boost (SIB) technique can optimize the target dose while protecting normal tissues. So, the investigators conducted this single-arm prospective phase II clinical trial to investigate the efficacy and safety of adjuvant SIB radiotherapy following narrow-margin(<1cm) hepatectomy in patients with HCC.

Inclusion Criteria:

• Pathological diagnosis of HCC after hepatectomy with narrow pathological margins (< 1 cm)
• Age > 18 years
• Recovery from surgery with an Eastern Cooperative Oncology Group performance status score of 0 or 1
• Child-Push Score: A5-A6
• Estimated life expectancy > 3 months
• No distant metastasis (M0)
• Blood routine examination: Hb≥80g/L, ANC≥1.0x10^9/L, PLT≥50x10^9/L
• Hepatic function: alanine transaminase(ALT) and aspartate transaminase(AST) ≤1.5 times ULN; or ALT ≤ULN and AST ≤6 times ULN exclude possibility of heart disease
• Renal function: creatinine(CRE) and blood urea nitrogen(BUN)≤1.5 times ULN
• Voluntary to participate and sign informed consent

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
• Duration from surgery ≥ 3 months