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ORIGINAL RESEARCH article

Front. Oncol.

Sec. Gastrointestinal Cancers: Colorectal Cancer

This article is part of the Research TopicMetallodrugs in Cancer TherapyView all 5 articles

Oxaliplatin versus Irinotecan as First-Line Therapy in Metastatic Colorectal Cancer with Prior Adjuvant Treatment: A Retrospective Study on Efficacy, Sequential Therapy, and the Impact of Thrombocytopenia

Provisionally accepted
  • Shanghai Cancer Center, Fudan University, Shanghai, China

The final, formatted version of the article will be published soon.

Background: The comparative efficacy of oxaliplatin versus irinotecan as first-line therapy in mCRC patients with prior adjuvant treatment remains unclear. Objectives: To compare the efficacy of first-line oxaliplatin-based versus irinotecan-based chemotherapy in metastatic colorectal cancer (mCRC) patients with prior adjuvant treatment and explore factors influencing survival outcomes. Methods: This retrospective single-center study analyzed 227 mCRC patients (2005–2014) receiving oxaliplatin (n=106) or irinotecan (n=121) as first-line therapy. Survival outcomes, treatment sequences, and adverse events were evaluated via multivariate analysis. Results: Compared with the irinotecan group, the oxaliplatin group had a numerically longer median OS (29.9 vs. 23.0 months; HR=0.75, p=0.043) but comparable PFS (9.2 vs. 9.4 months; p=0.722). Subgroup analysis confirmed consistent OS benefits with oxaliplatin regardless of prior adjuvant regimens. The chemotherapy interchange rates differed significantly (47% oxaliplatin→irinotecan vs. 28% irinotecan→oxaliplatin, p=0.004), although the treatment sequence did not affect OS (30.4 vs. 32.1 months; p=0.351). Thrombocytopenia during prior adjuvant therapy was more common in the irinotecan group (29% vs. 15%, p=0.016), which was correlated with oxaliplatin avoidance in subsequent lines. Multivariate analysis revealed that thrombocytopaenia itself was not an independent risk factor but influenced treatment selection. Conclusion: Despite the limitations of a retrospective, single-center design, first-line oxaliplatin provides superior OS in mCRC patients with prior adjuvant therapy, independent of the treatment sequence. The OS disparity stems from the differential use of chemotherapy interchange, driven by oxaliplatin-induced thrombocytopenia during adjuvant treatment, which may lead to premature regimen abandonment. Clinicians should prioritize thrombocytopenia prevention and avoid arbitrary oxaliplatin discontinuation. These findings highlight the importance of managing oxaliplatin-associated toxicity to preserve subsequent treatment options, though they require validation in prospective studies.

Keywords: metastatic colorectal cancer 1, oxaliplatin 2, irinotecan 3, first-line chemotherapy 4, adjuvant chemotherapy 5

Received: 29 May 2025; Accepted: 29 Oct 2025.

Copyright: © 2025 Shan, Huang, Zhou, Wang and Du. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Qiong Du, dujoan-88@163.com

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