Influenza Vaccination in Cancer Patients

Inclusion Criteria: 1. Patients who receive the scheduled cytotoxic chemotherapy every 3 weeks because of solid cancer. Specific definition of each term is like following: * The solid cancer includes various kinds of cancer except hematologic and lymphoid malignancies. * Cytotoxic chemotherapy includes adjuvant, neoadjuvant or palliative purpose of chemotherapy with the planned duration at least over 3 cycles every 3 weeks. * Targeted therapy drugs like as monoclonal antibody, tyrosine kinase inhibitor or oral chemotherapy drugs like as Xeloda are excluded. 2. Patients who did not receive the influenza vaccination yet in the current year. 3. Older than 19 years 4. Eastern Cooperative Oncology Group (ECOG) performance status is 0, 1, or 2 5. Cell blood count meets following criteria: * Neutrophile count ≥ 1.5 x 10\^9/L * Platelet count ≥ 100 x 10\^9/L * Hemoglobin ≥ 8 g/dL 6. Patients who can understand and agreed with the informed consents. Exclusion Criteria: 1. Patients who have any contraindication for influenza vaccination. 2. Patients who are supposed to receive the last chemotherapy at the enrollment 3. Patients who receive simultaneous radiation therapy with cytotoxic chemotherapy 4. Patients who receive any immunosuppressant (excluding steroid for anti-emetic effect) 5. Patients with HIV and low CD 4+ T cell count (\< 500/uL) 6. Patients with autoimmune disease who are anticipated to have a problem with immunogenicity for vaccine 7. Patients who have transplanted organ and receive immunosuppressants 8. Patients who are supposed to get prophylactic G-CSF after chemotherapy 9. Patients who are suspected to have active infectious disease.