Samatya Ratio: A Novel Prognostic Indicator for Rectal Cancer.

Objective: To evaluate the prognostic potential of a new parameter, the Samatya ratio, calculated by dividing tumour volume by the albumin-derived neutrophil-to-lymphocyte ratio (Alb-dNLR), in rectal cancer patients.

Study design: Descriptive study. Place and Duration of the Study: Department of General Surgery, Istanbul Education and Research Hospital, Istanbul, Turkiye, from January 2019 to October 2023.

Methodology: The analysis was conducted involving 86 patients diagnosed with rectal cancer who underwent surgery. Patients with ileus, tumour perforation or other confounding factors were excluded. Tumour volumes were calculated using MRI-based automated segmentation, while Alb-dNLR was obtained from preoperative laboratory data. The Samatya ratio was computed and analysed using ROC curve analysis, and its diagnostic performance was assessed for tumour perforation and carbohydrate antigen 19-9 (CA 19-9) marker elevation. Statistical significance was set at p <0.05.

Results: The mean Samatya ratio was 1177.64 ± 161. It was significantly associated with elevated CA 19-9 levels (p = 0.031) and tumour perforation (p = 0.003). At a cut-off value of >1069.34, the Samatya ratio demonstrated 72.7% sensitivity and 69.3% specificity for CA 19-9 levels (p <0.05), and at a cut-off value of >771.25, it demonstrated 84.6% sensitivity and 56.1% specificity for tumour perforation (p <0.05).

Conclusion: The results suggest that the Samatya ratio is a promising prognostic marker for rectal cancer, particularly in predicting tumour perforation and CA 19-9 levels. Its preoperative calculation may enhance prognostic assessment and guide clinical decision-making in oncology practice.

Key words: Rectal cancer, Alb-dNLR, Tumour volume, CA 19-9, Tumour perforation.