Use of combined biomarkers analysis to predict response to chemotherapy in colorectal cancer: A single-institution feasibility study

11074 Background: Treatment options for patients (pts) with colorectal cancer (CRC) have increased in the last years. However, there are no validated prospective molecular markers in CRC to select which agents are better to treat any individual case. The aim of this study was to determine the feasibility of developing an implementing a biomarker panel to guide treatment selection in this setting. Methods: Colorectal cancer tumors were prospectively analyzed with a predefined set of 11 molecular targets, including: KRas and PI3K mutations, EGFR amplification (FISH), and ERCC-1, TS, TP expression by IHC. Clinical characteristics and response to chemotherapy were registered. To establish the utility of this panel, we determine as congruent-treatment if the panel predict the best treatment in patients with more of 1 chemotherapy line and no-congruent-treatment if do not. Results: A total of 84 patients were studied. Only 6 % required a repeated biopsy to obtain sufficient tumor for marker analysis. In 81 % of patients was feasible to study almost 8/11 targets. There were 29 pts (39%) with KRas mutant CRC; 3 pts with PI3K mutations (4%, all of them with KRas mutation); and 2 patients with EGFR amplification. ERCC-1 was positive in 5/78 (6.4%) and TS was positive in 47%. None of 54 pts had TP positivity. Clinical floow up was available in 66 pts (44 males, median age 59, 93% ECOG 0–1). Nineteen patients had early CRC; 23 with metastatic CRC treated with a first line chemotherapy and 24 with advanced CRC treated with 2 or more prior regimens. In this last group for whom the response to multiple agents is known, the panel predictive the most effective treatment in 14 of 24 cases. Conclusions: This targeted-therapy-panel is feasible to implement and should be explore to predict treatment response to CRC . No significant financial relationships to disclose.