UGT1A1 Allele Test Not Only Minimizes the Toxicity But Also Maximizes the Therapeutic Effect of Irinotecan in the Treatment of Colorectal Cancer: A Narrative Review

BACKGROUND: Irinotecan is a first-line agent in the systematic treatment of colorectal cancer (CRC). Adjusting the dose of irinotecan according to the uridine diphosphate glucuronosyltransferase (UGT) 1A1 genotype reflects the principle of individualized and precision medicine, and may improve the chemotherapy response and survival of CRC. METHODS: To summarize the feasibility, efficacy and safety of high dose irinotecan in CRC patients with UGT1A1 wild-type or heterozygous alleles, PubMed, EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials online databases were searched from the date of creation to October 22, 2021. RESULTS: A total of 1,186 related literatures were searched, and 14 studies were included for review according to the inclusion criteria. The results indicated that the maximum tolerated dose of irinotecan in CRC patients with UGT1A1 wild-type or heterozygous variant was significantly higher than the conventional recommended dose. Chemotherapy based on high dose irinotecan improved the clinical efficacy in mCRC patients with UGT1A1*28 wild-type and heterozygous variant, and the toxicity was tolerated, as reflected in most studies. CONCLUSIONS: We are optimistic about the application of high dose irinotecan for mCRC patients with UGT1A1*28 wild-type or heterozygous variant, which will provide a relatively clear direction for future research and certain norms for clinical practice.