Maintenance Tegafur-uracil in Resected Oral Cavity Cancer With ECS+

Inclusion Criteria: * Patient must have histologically confirmed squamous cell carcinoma with primary site in the oral cavity. * Patient must have no distant metastasis in the pre-adjuvant radiotherapy evaluation. * Patient must have received surgical treatment with pathologically documented extracapsular spreading of lymph node. * Patient must have no CTCAE 4.0 grading≧2 acute adverse events from previous definite treatment at enrollment. * Patient must can be enrolled within 1 to 3 months after definite treatment. * Age between 20 and 70 years old; * Patient must have ECOG performance status score 0 or 1; * Patient must have adequate hematopoietic function which is defined as below: 1. white blood cell (WBC) ≥ 4,000/mm3; 2. platelet count ≥ 100,000/mm3; 3. absolute neutrophil count (ANC) ≥ 1,500/mm3; * Patients must have adequate hepatic function which is defined as below: 1. serum bilirubin level \< 1.5 mg/dl; 2. sGOT and sGPT \< 2.5 x ULN; 3. serum creatinine level \< 1.5 x ULN; * All women of childbearing potential must have a negative serum or urine pregnancy test prior to the start of study medication; * Patient with childbearing potential must agree to use a reliable contraceptive method during their participation in the study; * Patient must have the ability to understand and willingness to sign a written informed consent document. Exclusion Criteria: * Patient who has distant metastasis; * Patient who has serious concomitant illness which might be aggravated by chemotherapy; * Other malignancy within 5 years prior to study entry with exception of curative treated basal or squamous cell skin cancer or cervical carcinoma in situ. * Female patient who is pregnant or breast feeding.