Prognostic significance of inflammatory response markers for locally advanced squamous cell carcinoma of the external auditory canal and middle ear

We investigated the prognostic significance and treatment outcomes of pretreatment inflammatory response markers for locally advanced squamous cell carcinoma (SCC) of the external auditory canal (EAC) and middle ear (ME). Between July 2003 and July 2019, 21 patients with SCC of the EAC (n = 18) or ME (n = 3) who received radiotherapy with or without surgery or systemic therapy (radiotherapy alone [n = 2], radiotherapy + systemic therapy [n = 6], radiotherapy + surgery [n = 7], radiotherapy + surgery + systemic therapy [n = 6]) were retrospectively examined. The median radiation dose was 66.0 (range, 50.4-70.0) Gy, with daily fractions of 1.8-2.0 Gy. The median follow-up period was 25 months (range, 6-137). The two-year overall survival (OS), progression-free survival (PFS), and locoregional control (LC) rates were 61%, 48%, and 55%, respectively. OS, PFS, and LC did not differ significantly according to patient- (age, sex), tumor- (Pittsburgh stage, pretreatment neurological findings), and treatment-related (surgery or systemic therapy, radiation dose, prophylactic neck irradiation) factors. Conversely, there were significant differences in OS, PFS, and LC between patients with high and low pretreatment C-reactive protein-to-albumin ratios (p = 0.002, 0.003, and 0.004, respectively). OS also differed significantly between patients with high and low pretreatment neutrophil-to-lymphocyte ratios (NLR; p = 0.037). Other inflammatory response markers, including platelet-to-lymphocyte ratio (PLR) and albumin-to-globulin ratio (AGR), did not influence OS, PFS, or LC. Our findings suggest that pretreatment C-reactive protein-to-albumin ratio and NLRs have a significant impact on treatment outcomes in patients with locally advanced SCC of the EAC and ME.