• To compare the efficacy of Iodine-125 radioactive seeds implantation versus IMRT to treat inoperable salivary gland carcinoma.
• To compare the safety of Iodine-125 radioactive seeds implantation versus IMRT to treat inoperable salivary gland carcinoma.

The target population are those patients with inoperable salivary gland derived primary or recurrent cancer, including local advanced primary salivary gland cancer which could not be resected completely; recurrent salivary gland cancer which could not be resected completely; T3/T4 tumor which could not tolerate surgery due to severe combined disease. The subjects would be divided into Iodine-125 radioactive seeds permanent interstitial implantation brachytherapy and intensity-modulated radiation therapy randomly. During the follow-up period, the efficacy and the safety index would be monitored.

Inclusion Criteria:

• Patients are diagnosed histologically as primary or recurrent salivary gland cancers that may occur in either major salivary glands or minor salivary glands.
• The inoperable circumstance include: Primary or recurrent salivary gland cancers that could not be resected completely or could not get negative incision.
• T3/T4 tumor patients with severe medical comorbidities could not accept the high risk of perioperative complications.
• At least one measurable tumor or focus (according to RESIST 1.1 Standard).
• Karnofsky score> 60.
• Survival time predicted ≥ 3months;
• HGB≥9 g/dL, WBC≥3.0×10^9/L, NEUT≥1.5×10^9/L, platelet count (PLT)≥ 100×10^9/L; TBIL≤1.5 upper limit of normal, Alanine aminotransferase (ALT)/AST≤3 upper limit of normal; Cera≤1.5 upper limit of normal.
• Male or female with fertility in the experiment are willing to take contraceptive measures.

Exclusion Criteria:

• Radioactive therapy history of head and neck.
• Suffering from other malignant tumor in recent five years, except skin basal cell carcinoma or carcinoma in situs of cervix.
• Chemotherapy history.
• Receiving other effective therapy.
• Distant metastases.
• Pathologic result as squamous cell carcinoma.
• Neurological or mental abnormalities which affect cognitive ability.
• Severe cardiovascular and cerebrovascular diseases, such as heart failure (NYHA III-IV class), uncontrolled coronary heart disease, cardiomyopathy, uncontrolled arrhythmias, uncontrolled hypertension, myocardial infarction or cerebral infarction within past six months.
• Active serious clinical infections :> Class 2 NCI-Common Toxicity Criteria for Adverse Effects (CTCAE) Version 4.0 within 14 days before randomization, including active tuberculosis.
• HIV infection or active hepatitis B or hepatitis C.
• Uncontrolled systemic diseases, such as poorly controlled diabetes mellitus.
• Medical history of interstitial lung disease, such as interstitial pneumonia, pulmonary fibrosis, or baseline chest X-ray / CT showed evidence of interstitial lung disease;
• Pregnancy (via urine β-human chorionic gonadotropin test to determine) or breastfeeding.