UGT1A1 and malignant colon neoplasm: The National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology: Colon Cancer (Version 5.2024) similarly states that the dose of CPT-11 should be individualized based on the UGT1A1 genotype and that the initial dose of the drug should be reduced for patients identified as carriers of UGT1A1*28 purists.