Purpose: To clarify the clinical significance of determining plasma levels of vascular endothelial growth factor (VEGF) and soluble fms-like tyrosine kinase 1 (sFlt-1) in colorectal cancer, changes in plasma levels of VEGF and sFIt 1 during hepatic arterial chemotherapy were investigated in patients with liver metastases of colorectal cancer.
Patients and methods: The relationship between plasma level of VEGF or sFlt-1 and serum level of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), or the efficacy of hepatic arterial chemotherapy was investigated in patients with liver metastases of colorectal cancer (n=19). Plasma levels of VEGF and sFlt-1 were determined by the enzyme linked immunosorbent assay.
Results: There was a positive relationship between plasma level of sFlt-1 and serum level of CEA (p = 0.13). The other combinations did not show any statistical correlations. Also, in terms of the doubling time (DT), there was a positive relationship between the sFlt1-DT and the CEA-DT (p = 0.04). The levels of VEGF tended to change in accordance with the efficacy of chemotherapy. In contrast, plasma levels of sFlt-1 increased in patients with the progressive disease, whereas the levels did not decrease in patients with the partial response.
Conclusions: These results suggested that (1) VEGF may be a useful tumor marker during the chemotherapy in patients, whose CEA and CA19-9 are below the cutoff, and (2) the shrinkage of liver metastases may not cause a decrease in sFlt-1 or the half-life of sFlt-1 may be considerably long.