Clinical Trial of Chemosensitivity Test

Chemosensitivity Test to Evaluate the Effect of Adjuvant Cancer Chemotherapy (S-1) After Gastric Surgery

To evaluate the usefulness of chemosensitivity test in evaluating the appropriate adjuvant cancer chemotherapy after gastric surgery

Patients: clinical Stage III gastric cancer patients. Informed consent will be obtained before surgery. Eligible patients: surgical Stage II, IIIA and IIIB gastric cancer patients. Chemosensitivity test: The surgical specimen will be sent Mitsubishi BCL, Co. Ltd. to be tested by CD-DST chemosensitivity test and RT-PCR for thymidylate synthetase and dihydropyrimidine dehydrogenase mRNA. The test results will be blinded for the doctors on duty.

Treatment: All the patients will be treated with S-1 at a dose of 80 mg/m2 b.i.d. for 4 weeks followed by 2 weeks rest. The treatment will be continued until the recurrence or 1 year after operation.

Primary endpoint: 3-years disease-free survival rate Secondary endpoint: 3-years overall survival rate and side effect (CTCAE v3.0) Evaluation of chemosensitivity test: The cutoff condition will be determined based on the accumulated data of CD-DST and mRNAs.

Hypothesis: The responder detected by CD-DST and/or TS, DPD mRNA will have a favorable survival outcome comparing with resistant cases.

Inclusion Criteria:

• histologically proven gastric cancer
• PS (ECOG) 0 or 2
• D2 dissection, curability B or more
• surgical Stage IIIA and IIIB
• negative peritoneal cytology
• no previous radiotherapy, chemotherapy and hormone therapy
• possible peroral intake at 6 POW
• no severe surgical complication
• normal bone marrow, liver and renal function
• complete chemosensitivity test
• written informed consent

Exclusion Criteria:

• multiple cancer
• contraindication for S-1
• history of drug allergy (grade 3)
• severe complication
• watery diarrhea
• pregnant
• scirrhous gastric cancer
• the other patients who was judged as inadequate for trial by doctor on duty