This is an observational, retrospective, international and multicenter study funded by Fondazione Oncologia Niguarda ETS to assess the efficacy of anti-EGFR rechallenge regimens in the largest real-world cohort of MSS mCRC patients screened for RAS/BRAF/PIK3CA ctDNA status on liquid biopsy within the MEN1611-02 C-PRECISE-01 trial. The study will collect molecular, clinical and outcome data of patients already available at participating centers.

Patient's data to be collected include: age, gender, ethnicity; Eastern Cooperative Oncology Group scale performance status (ECOGPS); date of first diagnosis and date of advanced CRC diagnosis; primary tumor histology; timing of collection of FFPE and liquid biopsy samples; molecular profile data both from archival solid tissue and liquid biopsy; number and sites of metastasis at the time of liquid biopsy draw; medical treatment regimens, lines and locoregional approaches pursued, focusing on the first treatment received by patients following ctDNA analysis; date of death or last follow up. Response evaluation to therapies have to be assessed according to Response Evaluation Criteria in solid tumors (RECIST v1.1) criteria. Information will be provided about resposne to standard treatments (RR and DCR), duration of response (DOR), progression-free survival (PFS), time-to-treatment failure (TTF), OS.

Inclusion criteria

1. Patients diagnosed with MSS RAS and BRAF wild-type (on solid tissue) mCRC and screened by ctDNA within the MEN1611-02 clinical trial;
2. Informed consent signature from alive patient;
3. Availability of clinical data detailing the outcome to the first treatment received by patients following the blood draw for ctDNA analysis performed as per screening procedures within the MEN1611-02 clinical trial;
4. Signed informed consent for molecular screening within the MEN1611-02 clinical trial.
5. Age ≥ 18.

Exclusion criteria

1. No data available detailing the outcome to the first treatment received by patients following the blood draw for ctDNA analysis performed as per screening procedures within the MEN1611-02 clinical trial.
2. Patients enrolled and treated within the MEN1611-02 clinical trial.

Patients diagnosed with MSS RAS and BRAF wild-type (on solid tissue) mCRC

not yet decided