S-1-based regimens and the risk of leucopenic complications; a Meta-analysis with comparison to other fluoropyrimidines and non fluoropyrimidines

<b>Background</b>: We performed a meta-analysis oriented at the risk of leucopenic complications associated with S-1-based regimens. <b>Patients and methods</b>: The studies that were granted eligibility for inclusion include randomized phase II and III trials of patients with solid tumors on S-1; that entailed details of events of febrile neutropenia, all-grade and high-grade neutropenia and leucopenia. <b>Results</b>: After rejecting ineligible studies, a total of 28 clinical trials were elected eligible for further quantitative analysis. The RR of febrile neutropenia, all-grade and high-grade neutropenia for S-1 vs.non fluoropyrimidine controls was 0.27 [95% CI 0.16, 0.46; P <b>Conclusions</b>: The risk of febrile neutropenia, all-grade and high-grade neutropenia and leucopenia is less in S-1-based therapy than in non fluoropyrimidine regimens; yet comparable to the risk associated with infusional 5FU or capecitabine-based regimens.