Exploratory Study on the Association Between Pre-treatment Factors and Hematological Toxicity in Colorectal Cancer Patients Receiving CapeOX (Capecitabine Plus Oxaliplatin) Therapy

Background: The capecitabine plus oxaliplatin (CapeOX) regimen is commonly used for adjuvant treatment and selected first-line treatment settings in colorectal cancer.However, hematologic toxicities, such as leukopenia, neutropenia, anemia, and thrombocytopenia, may adversely affect treatment continuity, resulting in treatment delays, dose reductions, or treatment discontinuation.If these toxicities could be predicted based on pre-treatment blood test results and markers of inflammation and nutrition, it would lead to improved treatment continuity.In this study, we explored potential associations related to hematologic toxicities that occur at the end of the first cycle of CapeOX therapy.Methods: A retrospective analysis was conducted on 108 patients with colorectal cancer who began CapeOX therapy between September 2020 and October 2023.We evaluated hematologic toxicity (Grade ≥ 1) at the end of the first treatment cycle based on the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and examined its association with pre-treatment blood test results, nutritional indices (PNIs), and inflammatory markers (systemic inflammation response index (SIRI), systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR)).We performed multivariate logistic regression analysis on factors showing significant differences and calculated cutoff values using receiver operating characteristic (ROC) analysis.Results: An SII value of ≤496.8 was identified as a significant pretreatment factor associated with the development of leukopenia.For hemoglobin reduction, age ≥68 years, red blood cell count ≤394 × 10⁴/μL, and hemoglobin (Hb) ≤11.7 g/dL were associated; for thrombocytopenia, lymphocyte count ≤12.41 × 10²/μL and SII ≤477.9 were significantly associated.The identified associations may help generate hypotheses for future prospective studies of pre-treatment risk assessment and supportive-care strategies.Conclusions: Evidence suggests that some of the hematologic toxicities associated with CapeOX therapy show exploratory associations with pre-treatment blood tests and markers of inflammation and nutrition.These exploratory associations may help inform future hypothesis-generating research on pretreatment risk assessment and supportive-care strategies.