Circulating tumour DNA in patients with colorectal cancer undergoing curative-intent LIver MEtastases Surgery in France: a prospective, multicentre GERCOR G-118 CLIMES PRODIGE 77 cohort study protocol.

Curative-intent resection of colorectal cancer (CRC) liver metastasis (CRLM), combined with perioperative chemotherapy, is the standard of treatment for selected patients.

However, accurately predicting which patients will benefit from this strategy remains challenging. Circulating tumour DNA (ctDNA) has emerged as a promising non-invasive biomarker for detecting minimal residual disease and predicting prognosis.

This study aims to evaluate the prognostic value of ctDNA in patients with CRC undergoing surgery for CRLM. CRC patients undergoing LIver curative-intent MEtastasis Surgery is a prospective multicentre, observational cohort study designed to enrol 232 patients with upfront or potentially resectable CRLM. All patients will receive standard-of-care treatment. Serial blood samples will be collected at multiple time points: before chemotherapy (baseline, if applicable), before surgery, after surgery and during follow-up.

The primary objective is to assess the association between preoperative ctDNA status and disease-free survival. Secondary objectives include evaluating ctDNA dynamics over time, exploring associations with clinical and pathological features and identifying prognostic factors for recurrence and survival. ctDNA will be analysed using targeted next-generation sequencing and digital droplet PCR. Outcomes will be assessed using Kaplan-Meier survival analysis, Cox proportional hazards models and multivariable regression modelling. This protocol was approved by the Comités de Protection des Personnes Ouest-I Ethics Committee (N°2022-A02593-40) on 31 January 2023.

Study findings will be disseminated through peer-reviewed publications and relevant national and international conference presentations.

This study was registered in ClinicalTrials.gov (NCT05627681).