Systemic inflammatory markers: Predictors of survival in mucinous appendix cancer patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

<h2>Abstract</h2><h3>Introduction</h3> Inflammatory markers have been investigated as predictors of prognosis in various malignancies, but their role in mucinous appendix cancer (MAC) remains controversial. We evaluated the association between complete blood count-derived markers and survival in MAC patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). <h3>Methods</h3> We conducted a retrospective analysis of a single-center database (1998–2023) including newly diagnosed MAC patients who underwent complete (CC-0/1) CRS/HIPEC. Preoperative values of neutrophil-to-lymphocyte ratio (NLR), derived NLR, platelets-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) were calculated. For markers strongly associated with survival, we used time-dependent ROC analysis to define cutoffs to predict 5-year overall survival (OS). The Kaplan-Meier method with and Cox regression were employed for survival analysis. <h3>Results</h3> Of 626 CRS/HIPEC cases, 211 were eligible. NLR (p=0.049), dNLR (p=0.049), and MLR (p<0.001) were significantly associated with OS, while PLR was not. MLR demonstrated the strongest prognostic power (AUC=0.682) with the optimal cut-off 0.29. There were no significant differences in age, grade, or peritoneal cancer index (PCI) between patients with MLR<0.29 and MLR≥0.29. Five-year progression-free (PFS) and OS were 72.2 % and 83.2 % for MLR<0.29 and 54.2 % and 66.6 % for MLR≥0.29, respectively. After adjusting for age, PCI, and grade, MLR≥0.29 was associated with worse 3-year PFS (hazard ratio [HR] 1.74, 95 % confidence interval [CI]:1.02–2.97, p=0.044) and 3-year and 5-year OS (HR 1.87, 95 %CI: 1.00–3.47, p=0.049). <h3>Conclusion</h3> MLR has emerged as an independent predictor of survival in MAC patients undergoing CRS/HIPEC. Along with other prognostic factors, MLR≥0.29 may be potentially used for preoperative risk stratification.