Should we consider Systemic Inflammatory Response Index (SIRI) as a new diagnostic marker for rectal cancer?

Purpose The Systemic Inflammatory Response Index (SIRI), which depends on peripheral neutrophil, monocyte, and lymphocyte count, was found to be an effective prognostic indicator for various malignancies. In this study, we aimed to investigate the diagnostic value and the prognostic impact of SIRI on rectal cancer patients. Method The medical records of patients underwent sphincter-sparing rectal cancer surgery at general surgery between 2017 and 2022 were examined retrospectively. Patient demographics, operation types, neoadjuvant chemo/radiotherapies, pathological results, and complications were recorded. A total number of 99 patients who operated with diagnoses other than cancer were conducted as a control group. SIRI was calculated from preoperative peripheral blood samples' neutrophil, lymphocyte, and monocyte count. The optimal cut-off value for SIRI was found to be 1.38. The clinicopathological outcomes and Overall Survival (OS) were analyzed under two groups according to the SIRI values lower or higher than 1.38. Results The number of eligible patients was 104. The median age of the entire cohort was 62 (31-89). The median follow-up time was 33 (1-62) months. The median SIRI value in the study group was significantly higher compared with the control group. The study group was examined under two groups: SIRI 1.38 and SIRI > 1.38. The male gender was significantly more frequent in the high SIRI group. The remaining patient demographics and operation types were similar between the groups. The pathological outcomes were similar between the two groups. Overall Survival rate was better in the low SIRI group than those higher. The higher group had significantly higher complication rates than the lower SIRI group (p: 0.004). Conclusion SIRI may be a valuable diagnostic marker in rectal cancer patients. Higher SIRI levels were also associated with poorer prognosis and increased complication rates. Still, further prospective studies with a larger number of patients are needed.