Direct Observation of Retinal Microvessels in Cancer Patients After Systemic Administration of Bevacizumab and Oxaliplatin

Background/Aim: Antiangiogenic chemotherapy is the backbone of the various anticancer therapies. To date no practical biomarker predicting their antitumor effects and toxicity has been reported. We aimed to determine the feasibility of direct retinal observation as a practical biomarker in antiangiogenic chemotherapy. Patients and Methods: By direct retinal observation using a nonmydriatic retinal camera, we measured retinal microvessel diameters in 10 patients with colorectal cancer before and after intravenous infusion of bevacizumab and oxaliplatin. All patients also received oral capecitabine during their therapy. Results: Retinal microvessel diameters were decreased from baseline temporarily by 14.5±6.5% after infusion of bevacizumab and oxaliplatin in five patients who responded to treatment and 8.8±6.2% in the other five patients (p=0.008). Conclusion: Measurement of retinal microvessel diameters by direct observation appears to be feasible in patients receiving systemic chemotherapy. The decrease of retinal microvessel diameters might indicate improved tumor response to treatment with bevacizumab-containing systemic chemotherapy.