Systemic inflammation in response to malignancy can be quantified using the peripheral blood neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and lymphocyte-monocyte ratio (LMR). These biomarkers are strongly associated with adverse outcomes in advanced melanoma and other disseminated cancers, but the evidence is limited in relation to early stage melanoma. This study sought to investigate the association between these biomarkers and survival in stage I-III cutaneous melanoma.
This retrospective cohort study describes a consecutive series of patients who underwent wide excision and sentinel lymph node biopsy (SLNB) for cutaneous melanoma at a single institution over 10 years. We generated adjusted hazard ratios (HR) for overall survival and melanoma specific survival, with 95% confidence intervals (CI), for baseline NLR, PLR and LMR.
Five hundred and sixty-nine patients were included. The median follow up was 2·86 years (IQR, 1·67, 4·72; minimum 8 months, maximum 10·7 years). During surveillance, 67 (11·8%) participants died of which 57 (10%) were attributable to melanoma. Increased NLR was associated with increasing age and regression of the primary tumour. Improved overall survival was associated with a baseline NLR <2·5 (HR 3·49 [95% CI 1·36, 8·93], p=0·009) and PLR <100 (HR 2·78 [1·23, 6·32], p=0·014), whereas LMR was unrelated. A combined high NLR/PLR ratio was strongly predictive of overall survival (p=0.001). Peripheral blood biomarkers were not associated with melanoma-specific survival.
A decreased baseline NLR and PLR was associated with worse overall survival, which is dissimilar to previous studies and strengthens the hypothesis that the host immune response limits spread. Further studies are warranted to validate these findings.