Phase I Study of TS-1 With Concurrent Radiotherapy to Treat Pancreatic Cancer

Inclusion Criteria: * histologically or cytologically proven, newly diagnosed pancreatic adenocarcinoma or adenosquamous carcinoma * no previous radiotherapy, chemotherapy, targeted therapy, curative surgery, or immunotherapy used for pancreatic cancer * presence of at least one measurable lesion, which must meet the criteria of being ≥ 20 mm in at least one dimension by conventional CT/MRI or ≥ 10 mm by spiral CT scan * age between 20 and 79 years at registration * ECOG PS of 0 or 1 * adequate major organ functions * ability to take the oral study medication (TS-1) * no clinically significant abnormal ECG findings within 28 days (4 weeks) prior to registration * voluntarily signed the written informed consent form Exclusion Criteria: * pulmonary fibrosis or interstitial pneumonitis diagnosed within 28 days prior to registration * presence of diarrhea ≥ CTCAE v.4.03 grade 2 * concomitant active infection or significant co-morbid medical conditions * moderate or severe ascites or pleural effusion that requires drainage * central nervous system metastasis * prior or concurrent malignancies within the last 3 years * concomitant treatment with flucytosine, phenytoin or warfarin * pregnant women or nursing mothers, or positive pregnancy test * severe mental disorder * judged ineligible by physician for participation in the study due to safety concern