Irinotecan

Definition

Irinotecan is a chemotherapeutic agent derived from the plant alkaloid camptothecin, primarily used in the treatment of colorectal cancer. It works by inhibiting the enzyme topoisomerase I, which is essential for DNA replication and transcription, ultimately leading to cancer cell death. This makes irinotecan an important component of combination therapies for various malignancies, especially in the context of colorectal cancer.

5 Must Know Facts For Your Next Test

1. Irinotecan is commonly used in combination with other chemotherapy agents, such as fluorouracil and leucovorin, to enhance treatment efficacy for colorectal cancer.
2. It can cause side effects like diarrhea and neutropenia, which are important to manage during treatment.
3. The drug is administered intravenously and may be given either as a continuous infusion or as a short-term infusion depending on the treatment regimen.
4. Patients may require genetic testing to determine their ability to metabolize irinotecan effectively due to variations in the UGT1A1 gene.
5. Irinotecan's mechanism of action involves trapping the topoisomerase I-DNA complex, leading to DNA damage and triggering apoptosis in cancer cells.

Review Questions

• How does irinotecan function at the molecular level to treat cancer, and why is this important for patient outcomes?
  • Irinotecan functions by inhibiting topoisomerase I, an enzyme crucial for DNA replication. By trapping the topoisomerase I-DNA complex, it causes irreversible DNA damage which ultimately leads to cell death. Understanding this mechanism is vital because it informs how the drug can be effectively combined with other agents and helps predict which patients may respond better based on their genetic makeup.
• Discuss the significance of genetic testing for UGT1A1 when using irinotecan and its implications on treatment plans.
  • Genetic testing for UGT1A1 is significant when using irinotecan because variations in this gene can affect how well patients metabolize the drug. Individuals with certain genetic polymorphisms may experience increased toxicity or reduced efficacy from standard doses. This information can guide oncologists in customizing treatment regimens, ensuring optimal dosing and minimizing adverse effects for better patient outcomes.
• Evaluate the role of irinotecan in combination therapy for colorectal cancer and how this approach influences overall survival rates.
  • Irinotecan plays a critical role in combination therapy for colorectal cancer, particularly when paired with fluorouracil and leucovorin. This multi-drug approach enhances therapeutic efficacy by targeting cancer cells through different mechanisms simultaneously. Clinical studies have demonstrated that such combinations can significantly improve overall survival rates compared to single-agent therapies, showcasing the importance of irinotecan within comprehensive treatment strategies for more effective management of advanced colorectal cancer.

Related terms

Topoisomerase I: An enzyme that helps to relieve torsional strain in DNA by making temporary cuts, allowing for proper DNA replication and transcription.

Camptothecin: A natural alkaloid that serves as the parent compound for several derivatives, including irinotecan, known for its anticancer properties.

Colorectal cancer: A type of cancer that starts in the colon or rectum, often treated with chemotherapy agents like irinotecan as part of a broader treatment strategy.