The only curative option for pancreatic cancer patients is surgery, but the patients within 20% of them are possible for a radical surgery. Accordingly, concurrent chemo-radiation therapy is generally used for palliation of unresectable pancreatic cancer patients. So far, the use of 5-fluorouracil (5-FU) was the traditional method of chemotherapy. However, these days, oral anti-cancer medicine, capecitabine(Xeloda®), was developed and considered as an alternative medicine of 5-fluorouracil (5-FU). Furthermore, according to the recent results of clinical trials, the clinical use of capecitabine(Xeloda®) with radiation therapy was proved to be very effective and safe. The purpose of this trial is to improve the therapeutic effects by using proton therapy and chemotherapy concurrently.

Inclusion Criteria:

• There is no evidence of metastatic disease in the major viscera and no peritoneal seeding
• Patients with biliary or gastroduodenal obstruction must have drainage prior to starting chemoradiation
• All malignant disease must be encompassable within a single irradiation field (15x15cm maximum)
• All patients must have radiographically assessable disease
• No previous irradiation to the planned field
• Age of ≥18 years
• performance status of 0 to 2 on the Eastern Cooperative Oncology Group (ECOG) score
• Required Entry Laboratory Parameters WBC count ≥ 2,000/mm3;(ANC>1,000), hemoglobin level ≥ 7.5 g/dL; platelet count ≥ 100,000/mm3; total bilirubin ≤ 3.0 mg/dL (Patients with elevated bilirubin due to obstruction should be stented and their bilirubin should be decreas ≤ 3.0 mg/dL prior to study entry); creatinine ≤ 3.0 mg/dL
• Oral intake (including J-tube feeding) of ≥ 1,500 calories/day should be maintained.

Exclusion Criteria:

• There is evidence of metastasis in the major viscera or peritoneal seeding.
• Age of <18 years
• Previous history of RT adjacent to planned field
• poor performance status of 3 to 4 on the Eastern Cooperative Oncology Group (ECOG) score
• pregnant or breast feeding status
• previous history of uncontrolled other malignancies within 2 years