Purpose: To analyse the prognostic role of the immunohistochemical expression of pKDR in patients with advanced colorectal cancer treated with oxaliplatin and fluoropyrimidines combination chemotherapy with or without bevacizumab.
Methods: Retrospective multicentre study, carried out at four hospitals in the Valencian Community (Spain). Patients evolution was compared based on the immunohistochemical expression of pKDR, classified using 4 categories: 0 (undetectable), 1 (mild), 2 (moderate) and 3 (high intensity). Patients were divided into two groups for the analysis: group 1 with low expression (0-1) vs. group 2 with high expression (2-3).
Results: Histological samples for the pKDR analysis were available for 84 of the 112 patients selected. Seven (8.3 %) had undetectable or mild expression of pKDR (Group 1) and 77 (91.7 %) showed moderate or high expression of pKDR (Group 2). Response rate in Group 1 was 100 % compared to 54.2 % in Group 2 (p = 0.019). Progression-free survival (PFS) (15 vs. 12 months, p = 0.4) and overall survival (OS) (28 vs. 22 months, p = 0.09) were numerically but not significantly higher in patients from Group 1 vs. Group 2. Patients from Group 2 who received bevacizumab presented a significantly higher PFS (13 vs. 11, p = 0.015) and a numerically higher OS (23 vs. 17 months, p = 0.27) than those treated exclusively with chemotherapy.
Conclusions: Our results suggest that the absence or low expression of pKDR is associated with a better prognostic profile in patients with advanced colorectal cancer treated with chemotherapy and bevacizumab. Patients with a high pKDR expression benefit from the combination of chemotherapy with bevacizumab.
Keywords: Bevacizumab; Biomarkers; Colorectal cancer; pKDR.