This study is designed to compare the efficacy and safety of FOLFIRI regimen with irinotecan monodrug in the treatment of advanced colorectal cancer patients in the second-line setting.

Inclusion Criteria:

• aged 18-70 years with histologically or cytologically confirmed advanced colorectal adenocarcinoma
• Eastern Cooperative Oncology Group performance status of 0 to 2
• life expectancy of ≥ 3 months
• patients who had failed first-line treatment with either XELOX (capecitabine combined with oxaliplatin) or FOLFOX (5-fluorouracil/leucovorin with oxaliplatin)
• at least one measurable disease lesion according to the Response Evaluation Criteria in Solid Tumors (RECIST 1.1) criteria
• have adequate bone marrow, hepatic, and renal function

Exclusion Criteria:

• patients with previous chronic inflammatory bowel disease, chronic diarrhea or recurrent bowel obstruction
• patients with symptomatic brain metastases
• active clinical severe infection
• previously received irinotecan
• dihydropyrimidine dehydrogenase (DPD) enzyme adequate