Monitoring levels of circulating cell‐free DNA in patients with metastatic colorectal cancer as a potential biomarker of responses to regorafenib treatment oleh Brice Pastor, Thierry André, Julie Henriques, Isabelle Trouilloud, Christophe Tournigand, Marine Jary, Thibault Mazard, Christophe Louvet, Simon Azan, Audrey Bauer, Benoit Roch, Cynthia Sanchez, Dewi Vernerey, Alain R. Thierry, Antoine Adenis