Investigators propose to assess, retrospectively (from 1/7/2009) and prospectively (up to 31/12/2013,) the safety and tolerability profile (number of participants with adverse events) of standard chemotherapy and anti-angiogenic agent bevacizumab (Avastin) as first line treatment of patients with metastatic Colorectal Cancer with or without KRAS mutation. All treatment schedules that are going to be assessed are considered by the international guidelines as standard therapy for patients with metastatic Colorectal Cancer.

In addition investigators propose to assess the compliance of patients to treatment and the efficacy of treatment. That means percentage of objective responses, duration of response, frequency of curative liver resection after the administration of treatment, progression free survival and estimation of overall survival

Inclusion Criteria:

• Written informed consent
• Histologically confirmed metastatic or locally advanced non-operable colorectal cancer
• No prior first line treatment for metastatic colorectal cancer
• Age ≥18 years
• One or more measurable lesions (≥1cm in diameter with spiral CT scan or ≥2cm with conventional techniques) according to RECIST criteria
• ECOG performance status ≤2
• Adequate haematological, renal and hepatic function
• Urine protein <2+ (dipstick)
• Life expectancy of ≥12 weeks

Exclusion Criteria:

• Previous first line treatment for metastatic colorectal cancer(progression >6 months after the end of adjuvant treatment)
• Previous radiotherapy to target lesions
• Patients with brain metastases and/or cancerous meningitis
• Metastatic infiltration >50% of the liver parenchyma
• Presence or history of other neoplasm except properly treated basal cell skin cancer or in situ cervical carcinoma
• Patients participating in interventional clinical trial

Clinics for cancer prevention