This is a phase IV multicenter trial to evaluate real-world health outcomes, economic impact and resistance mechanisms of panitumumab in the treatment of patients with chemotherapy-refractory metastatic colorectal cancer (mCRC).

This study will address two anticipated issues surrounding personalized medicine and treatment with panitumumab. First, it will enable to assess the economic impact of panitumumab in a real-life setting (HEOR study). Second, it will identify new blood-based mechanisms of resistance, which may lead to new avenues for combination therapy in metastatic colorectal cancer (Blood study).

The primary objective is to collect information on quality of life and health care resource utilization by patients diagnosed with metastatic colorectal cancer. The secondary objectives are to confirm survival data, to assess the quality of life of patients and to assess the health care resource utilization of patients. The blood biomarker study objective is to determine blood-based biomarkers of response or resistance to panitumumab.

Patients with a mutated KRAS gene will be treated with standard-of-care (SOC) and will participate to the HEOR study only. Patients with a non-mutated (wild type) KRAS gene will be treated with panitumumab and will participate to the HEOR study and to the blood biomarker study.

During the course of the study, data will be collected on quality of life and work productivity. Patients will be asked to fill a set of questionnaires at their recruitment in the study and at every 3 months after treatment initiation. For patients participating to the blood study (patients with a wild type KRAS), blood samples will be collected before patients start their treatment, at every treatment and when they discontinue their treatment.

Inclusion Criteria:

• Patients with a histologically confirmed diagnosis of mCRC.
• Immunohistochemical evidence of EGFR expression.
• ECOG performance status of 0, 1 or 2.
• Patients refractory to fluoropyrimidine, oxaliplatin, and irinotecan chemotherapy regimens
• Patients with a wt KRAS scheduled to receive panitumumab as a single agent for the third-line treatment of mCRC or patients with a mt KRAS scheduled to receive SOC for third-line treatment of mCRC.
• Signed and dated IRB-approved informed consent document.
• Ability to read and understand English or French.
• 18 years of age or older.

Exclusion Criteria:

• Acquired immunodeficiency syndrome (AIDS-related illnesses) or known HIV disease.

Patients with chemotherapy-refractory metastatic colorectal cancer from participating hospitals in Quebec.