e14142 Background: Although FOLFOX regimen is shown to be effective to suppress the recurrence of stage III colorectal cancer (CRC) who received curative resection, the prophylactic effect of has not fully been investigated in adjuvant setting of stage IV CRC cases, namely, after curative resection of distant metastases. Methods: This is a retrospective study including 116 CRC patients with synchronous metastases and 91 with metachronous metastases who received curative resection in our hospital between 2000 and 2009. Pathological parameters of primary CRC, postoperative chemotherapeutic regimen, relapse-free survival (RFS) were analyzed retrospectively. Results: After resection of CRC and synchronous metastases, 53 (84%) out of 63 patients without chemotherapy, and 38 (83%) out of 46 that received oral or intravenous 5-fluorouracil (5-FU) alone or with leucovorin (LV) developed recurrent tumors. By contrast, only single patient (17%) among 6 who underwent FOLFOX showed recurrence. With a median follow-up period of 775 days, the FOLFOX group exhibited a significantly improved RFS as compared to the 5-FU(+LV) or surgery alone group (p=0.03, p=0.007, respectively). The 5-year OS rates of the surgery alone, 5-FU(+LV), and FOLFOX group were 67%, 75%, and 100%. In CRC cases with metachronous metastases, on the other hand, the recurrence rate of the group without chemotherapy was 63%, and that of the 5-FU (+LV) group 55%. In 7 patients who underwent FOLFOX chemotherapy (5 cases of FOLFOX4 and 2 cases of mFOLFOX6, no antibody therapy) after metastasectomy, 71% (5 patients) relapsed afterward. Thus, the tumor-relapse rate after metastasectomy was similar among patients who received no postoperative chemotherapy. The median RFSs of the surgery alone, 5-FU(+LV), and FOLFOX groups were 323, 917, and 322 days, respectively. Conclusions: Adjuvant FOLFOX is certainly beneficial for stage IV CRC patients with synchronous metastasis who received curative resection. In contrast, the prophylactic effect of FOLFOX is not superior to other follow-up strategies in patients who received complete resection of metachronous metastases.