LAUSR

577 Background: Vascular endothelial growth factor (VEGF) signals may change during colorectal cancer (CRC) treatment, but monitoring real time changes has not been conducted. Methods: Blood monitoring was carried out to track changes in the status of VEGF ligands (A, C, and D) in CRC patients. Expression was determined by ELISA. Results: VEGF-A monitoring was performed in 148 CRC patients preoperatively and VEGF-C and -D monitoring was performed in 52 metastatic CRC patients. Patients with high VEGF-A had significantly shorter recurrence free survival (p = 0.00438). Univariate analysis associating with recurrence detected high VEGF-A, high pathological stage, and with lymph node metastasis were risk factors, and high VEGF-A was identified as an independent risk factor of recurrence by multivariate analysis. There was no significant difference in prognosis between metastatic CRC patients with high and low VEGF-D in early-line treatment, however, in late line patients with high VEGF-D had significantly worse prognosis than those with low VEGF-D (p = 0.0121). When they had treatment with bevacizumab, same result was seen in late line (p = 0.0416). VEGF-C showed no significant correlation with prognosis. Conclusions: Preoperative high VEGF-A is an important risk factor of recurrence and VEGF targeting drugs might be useful as an adjuvant chemotherapy for the patients with high VEGF-A. In late line chemotherapy, patients with high VEGF-D had poor prognosis in regardless of bevacizumab, therefore, they will be candidates of other anti-VEGF drugs than bevacizumab in late line chemotherapy. Measurement of plasma VEGF level can have benefit for the treatment of CRC patients to predict their recurrence and prognosis. It would be helpful for VEGF targeting drug selection and provide useful information for better treatment strategy.