3562 Background: Angiogenesis has been correlated with increased invasion and metastases in a variety of human neoplasms. Inadequate inhibition of the growth of tumor microvessels by anticancer agents may result in treatment failure, rated clinically as progressive or stable disease. We designed this trial to investigate if Vascular Endothelial Growth Factor (VEGF) circulating levels modifications may be related with clinical response and outcome in advanced colorectal cancer patients during treatment with a weekly combination of cetuximab plus irinotecan. Methods: 45 heavily pretreated metastatic colorectal cancer patients were prospectively evaluated for circulating levels of VEGF during the treatment with cetuximab (initial dose of 400 mg per square meter, followed by weekly infusions of 250 mg per square meter) plus weekly irinotecan (90 mg per square meter). VEGF circulating levels were assessed at the following time-points: just before and at 1, 21, 50 and 92 days after the start of cetuximab plus irinotecan treatment. Results: Basal serum VEGF median levels were significantly decreased just at the first day (after the first treatment infusion (P=0.016). The VEGF persisted at the following time points reaching the highest statistical significance 92 days after the first infusion (P<0.0001). Twenty-two patients showed a reduction in median VEGF circulating levels of at least 50% 92 days after the first infusion respect to the basal time point. In the group of patients with at least 50% reduction of VEGF levels the response rate was 59.1% vs 21.7% in the non reduced VEGF group (P=0.024). Moreover, the median time to progression was 6.12 months (95% C.I.: 3.9 - 7.1) in the reduced VEGF group vs 2.3 months (95% C.I.: 1.6 - 3.5) in the other patients (P=0.001). Finally, also overall survival was longer in patients who developed VEGF reduction (12.3 months; 95% C.I.: 8.65 - 15.9) than this recorded in patients without the reduction (6.4 months; 95% C.I.: 5.6 - 8.4) (P=0.05). Conclusions: The present data represent the first evidence that suggest a role of VEGF reduction in the prediction of efficacy of treatment with cetuximab plus weekly irinotecan in heavily pretreated advanced colorectal cancer patients. No significant financial relationships to disclose.
Abstract No. 26 Combined portal vein and hepatic vein embolization in heavily pretreated colorectal cancer patients undergoing major hepatic resection: experience in a single cancer US center
