Clinical value of chip-based digital-PCR platform for the detection of circulating DNA in metastatic colorectal cancer.

Abstract Background The detection of circulating DNA is considered a promising strategy in cancer patients. Digital PCR has emerged as a sensitive method able to quantify both circulating free and tumour DNA. Aim The aim of this study was to prospectively evaluate the clinical value of a chip-based digital PCR for the detection of circulating DNA. Methods Digital PCR was used in 34 metastatic colorectal cancer patients to detect and quantify circulating free and tumour DNA based on K-ras mutational status. Clinical outcomes were analyzed according to circulating DNA measurements. Results Digital PCR yielded a detection rate of 69% for circulating tumour DNA. The median concentrations of circulating free and tumour DNA were 20 and 6.8 ng/mL, respectively, with significant correlation between both biomarkers ( p 75% quartile) versus not reached in patients with a low level ( p  = 0.029). Moreover, median overall survival was significantly decreased in patients with detectable circulating tumour DNA compared to those without (respectively 11.8 months versus not reached, p  = 0.04). Conclusions Chip-based digital PCR is a simple and non-invasive method allowing the efficient detection of circulating DNA. Our results highlight that levels of these circulating markers may have a potential prognostic value.