It is a randomized phase II study to determine the efficacy and safety of particle therapy with or without apatinib as induction therapy for the treatment of head and neck adenoid cystic carcinoma. Participants will be randomized to arm 1: receiving apatinib for 6 weekly followed by particle radiotherapy; arm 2: particle radiotherapy alone.

The purpose of this study is to determine the efficacy and safety of particle therapy with or without apatinib as induction therapy for the treatment of head and neck adenoid cystic carcinoma. It is a randomized phase II clinical trial with single phase and 2 experimental arms. Participants will be randomized to arm 1, receiving apatinib (0.5g, daily) for 6 weekly followed by particle radiotherapy (proton: 56 GyE/28 Fx, plus carbon: 15 GyE/5 Fx for boost); arm 2: particle radiotherapy alone (proton: 56 GyE/28 Fx, plus carbon: 15 GyE/5 Fx for boost). The short term response will be evaluated using RECIST criteria. And the acute and late toxicities will be evaluated according to NCI CTCAE v4.03.

Inclusion Criteria:

• Pathologically confirmed ACC
• Inoperable disease or postoperative residual disease detected by imaging studies
• Age ≥ 18 and ≤ 65 years of age
• ECOG < 2, no significant active concurrent medical illnesses
• Adequate laboratory values within 30 dyas of enrollment to study defined as follows: N > 2000/mm^3; PLT > 100,000/mm^3; total bilirubin < 1.5mg/dl; AST/ALT < 1.5 ULN; SCr < 1.5mg/dl; CCR > 60ml/min
• Willing to accept adequate contraception for women with childbearing potential
• Ability to understand character and individual consequences of the clinical trial
• Willing to sign the written informed consent; Informed consent must be signed before the enrollment in the trial

Exclusion Criteria:

• Presence of distant metastasis
• Pregnant or lactating women
• A diagnosis of malignancy other than CIS of the cervix, BCC and SCC of the skin within the past 5 years
• Refusal of the patient to participate into the study