Efficacy and safety of irinotecan-based chemotherapy for advanced colorectal cancer outside clinical trials: an observational study.

Background: This prospective observational study in typical community-based outpatient clinics evaluated the efficacy and toxicity of weekly and biweekly irinotecan-based chemotherapies and their compatibility depending on age.

Methods: 601 patients with advanced or metastatic colorectal cancer receiving first-, second-, or third-line irinotecan-based therapy were regularly analyzed for response and toxicity until the end of therapy.

Results: The median age was 65 (28-87) years, approximately one-third of the patients were ≥70 years old. Of all patients, 405 were treated weekly and 68 biweekly. Median overall survival (OS) for first-line therapy was 26.5 months for the <70-year-old patients and 19.4 months for the ≥70-year-old patients. Toxicities were moderate in all groups. Tumor growth control rates (TCR) and median time to progression (TTP) were marginally better for patients <70 years old. Median TTP was 9.9 months in first-line therapy, 9.8 months after adjuvant therapy, 7.7 months in second-line, and 6.4 months in third-line therapy.

Conclusions: Toxicity and response data from this observational study clearly confirm the positive results from previous clinical studies and show a slight ad-vantage in efficacy for the <70-year-old patients.