The chemotherapy monitoring is currently based on radiological (RECIST 1.1 guideline) and
clinical evaluation every 3 months. Circulating markers as Carcino Embryonic Antigen (CEA),
circulating tumour DNA and total cell free DNA represent an alternative approach to evaluate
the response. In the field of metastatic colorectal cancer (mCRC) recent studies suggest that
early evaluation could be clinically relevant. Indeed, early tumoral response seems to be
correlated to overall survival. Moreover, post-operative morbidity increases with the number
of prior chemotherapy treatments. Early evaluation could allow to modify chemotherapy
regimens when response appears to be insufficient.
The aim of the present study is to evaluate, in a prospective cohort of patients treated with
systemic IV chemotherapy (5 Fluorouracil +/- oxaliplatin +/- irinotecan) +/- targeted therapy
as first line treatment for a mCRC, the correlation between early variations of circulating
tumour markers including CEA, circulating tumour DNA and total cell free DNA, and the 3
months objective response as defined in the RECIST 1.1 guideline.