Systemic redox imbalance correlates with clinical aggressiveness and poor prognosis in canine inflammatory mammary carcinoma

Introduction Canine inflammatory mammary carcinoma (IMC) is a highly aggressive neoplasm characterized by rapid clinical progression, high metastatic potential, and poor prognosis. Increasing evidence suggests that systemic redox imbalance, resulting from a disproportion between reactive oxygen species and antioxidant defenses, plays a key role in tumor progression. This study evaluated serum total antioxidant capacity (TAC) and malondialdehyde (MDA) as systemic biomarkers of redox status in female dogs with IMC and non-inflammatory mammary tumors (NIMTs). Methods Serum TAC and MDA levels were measured in 49 female dogs aged 8–18 years. The cohort included dogs with IMC ( n = 20) and dogs with NIMTs ( n = 29), the latter subdivided into aggressive tumors ( n = 11) and low-grade tumors ( n = 18). Biomarker levels were compared among groups and correlated with clinical aggressiveness and overall survival. Results Systemic redox imbalance was significantly more pronounced in dogs with IMC. Serum MDA levels were markedly higher in the IMC group (3558.9 nmol/mL) than in dogs with aggressive (53.3 nmol/mL) or low-grade tumors (48.3 nmol/mL) ( p < 0.001). In contrast, TAC levels were significantly lower in the IMC group (9.8 mmol/L) compared with the aggressive (14.0 mmol/L) and low-grade groups (12.6 mmol/L) ( p < 0.001). Survival analysis confirmed the extremely poor prognosis associated with IMC, with a median survival of 16 days and 100% mortality, whereas 94.4% of dogs with low-grade tumors survived until the study endpoint (698 days). Higher MDA levels were strongly associated with shorter survival and greater clinical aggressiveness in IMC cases (p < 0.001). Discussion These findings demonstrate that systemic redox imbalance is closely associated with the rapid progression and poor survival observed in canine IMC. Serum TAC and MDA may serve as valuable prognostic biomarkers and support the relevance of oxidative stress as a potential therapeutic target in aggressive mammary neoplasms. These results may also have comparative implications for human oncology.