Observational, non randomized study aimed at measuring the effect of chemotherapy in the urinary concentrations of physiological modified nucleosides in 30 patients with metastatic colorectal cancer.

Inclusion Criteria:

• Histologically-confirmed metastatic colorectal cancer;
• 0 to 3 prior chemotherapy lines;
• Signed informed consent;
• Good understanding of the protocol and of the follow-up;
• Estimated life expectancy exceeding 3 months;
• At least one measurable metastatic lesion (RECIST criteria);
• Performance Status (WHO) of 0 to 2;
• Good haematological, hepatic and renal functions.

Exclusion Criteria:

• More than 2 surgical resections of metastases from colorectal cancer;
• Poor performance status (>2);
• Poor haematological, hepatic or renal functions;
• Uncontrolled chronic disease;
• Serious unhealed wound, ulcer or fracture within the previous month;
• Clinical or laboratory finding suggesting possible abnormalities in nucleosides urinary excretion;
• Pregnancy or breast-feeding during the previous month;
• Transmeridian trip of more than 4 time zones within the prior 2 weeks;
• Person with legal restriction to participate into clinical research, according to the current law in France.

Patients with metastatic colorectal cancer treated at the Department of Medical Oncology of Paul Brousse Hospital