Background Acral melanoma (AM) is a highly aggressive skin cancer associated with high mortality. In this study, we measured inflammatory biomarkers, identified cutoff values, and developed a scoring system to predict mortality in patients with AM. Aims This study aimed to identify inflammatory biomarker cut-off points and factors in AM patients, introducing the Acral Melanoma Inflammatory Risk Index (AMIRI) to predict mortality. Methods In this retrospective cohort study, we analysed 394 patients diagnosed with AM. Demographic and clinicopathological data were obtained from medical records. Inflammatory markers (neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and absolute neutrophil count (ANC)) were measured at diagnosis. The AMIRI scoring system was used to categorise patients into three risk groups: low (AMIRI ≤ 1), intermediate (1 < AMIRI ≤ 2), and high (AMIRI > 2). We used logistic regression models to evaluate associations between inflammatory markers and mortality. Results The median age of the 394 AM patients was 67 years. The AMIRI scoring system effectively categorised patients into risk groups, with higher scores correlating with increased mortality risk. The Cox model showed a significant increase in 5-year mortality risk for moderate [OR 1.94] and high [OR 1.96] AMIRI risk groups compared to low-risk patients. Limitations This study has limitations, including its retrospective design, being conducted at a single center, incomplete data on adjuvant therapy, and the exclusion of immunotherapy from biomarker analysis, with potential biases from factors like steroid use and associated diseases. Conclusion Inflammatory biomarkers are valuable prognostic tools in AM. The AMIRI scoring system effectively stratifies patients, identifying those with higher mortality risk.
Keywords: Absolute neutrophil count; acral melanoma; inflammatory biomarkers; neutrophil-to-lymphocyte ratio; platelet-to-lymphocyte ratio.