Introduction Excess oxidative stress is generated by inflammation and cancer, and it is involved in the development and metastasis of colorectal cancer. However, there are few reports on the relationship between blood oxidative stress and prognosis. This study examined the usefulness of derivatives of reactive oxygen metabolites (d-ROMs), a measure of oxidative stress, and the neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, as prognostic markers in colorectal cancer. Methods The study enrolled 163 patients who underwent colorectal cancer resection at our institution between 2013 and 2018. Blood samples were taken preoperatively to measure d-ROMs and NLR. Spearman’s correlation analysis was used to examine the relationships between d-ROMs and NLR, and Cox regression analysis was performed to identify factors associated with d-ROMs and NLR. The Kaplan–Meier method was used to calculate disease-specific survival (DSS). Results There was no correlation between d-ROMs and NLR. Tumor size was significantly associated with d-ROMs and NLR. DSS was significantly worse among patients with high d-ROMs or high NLR, although patients with high d-ROMs and high NLR had the worst DSS. In the multivariate analysis, distant metastasis and the high d-ROM/NLR combination were significant factors associated with DSS (P < 0.001, hazard ratio [HR] = 22.880 and P = 0.049, HR = 2.391, respectively). Conclusion Preoperative d-ROMs and NLR reflect the tumor size among patients with colorectal cancer. The combination of d-ROMs and NLR may effectively predict prognosis in patients with colorectal cancer.

Introduction: Extramural vascular invasion in patients with rectal cancer is a poor prognostic factor associated with distant metastasis; thus, accurate preoperative diagnosis is important. However, the accurate detection of extramural vascular invasion using magnetic resonance imaging is difficult, and an improved diagnostic modality is required. In addition, the factors involved in the formation of EMVI remain unclear. In this study, we aimed to examine the ability of [18F] FDG PET/MRI to detect EMVI and　elucidate the factors involved in EMVI. Methods: Thirty-one patients with rectal cancer were enrolled in this study between 2017 and 2021. We preoperatively evaluated the pelvic 18F-fluorodeoxyglucose positron emission tomography/ magnetic resonance imaging([18F] FDG PET/MRI) to detect extramural vascular invasion ([18F] FDG PET/MR-defined EMVI: pmrEMVI). To investigate the factors related to pmrEMVI, we confirmed the desmoplastic reaction and TWIST expression in the primary lesions of rectal cancer and examined its relationship with pmrEMVI. Results: Six of the 31 patients were pmrEMVI-positive. Four pmrEMVI-positive patients had distant metastases. The levels of immature desmoplastic reaction and TWIST1 expression were significantly higher in cases with pmrEMVI positivity. Conclusion: PmrEMVI is a useful biomarker for predicting distant metastasis. In addition, pmrEMVI was significantly correlated with factors related to tumor invasiveness.