Introduction: The purpose of this study was to determine the prognostic utility of vitamin D concentrations and BMI (body mass index) values and the systemic immune-inflammation index (SII), the systemic inflammation response index (SIRI) and the pan-immune-inflammation value (PIV) to predict the achievement of a complete response to neoadjuvant treatment (NAT) in patients with breast cancer. The correlations between systemic inflammatory response indices and vitamin D concentrations and BMI values were also analysed.
Material and methods: The study included 96 patients with breast cancer, prior to the start of NAT, of which 51 patients were diagnosed with triple-negative breast cancer (TNBC) and 45 patients with human epidermal growth factor receptor type 2 (HER2)-positive type.
Results: The SIRI and PIV indices were shown to be significantly higher in patients with TNBC (P = .001; P = .001) than in patients with HER2. There were no statistical differences in SII, SIRI, PIV, BMI, and vitamin D, according to the response to NAT treatment (pCR vs non-pCR). In the HER2+ group without pCR after NAT, there was a positive correlation of the SII coefficient with BMI values (R = .41; P = .045). Furthermore, in the entire HER2+ group (irrespective of the NAT response), SII values were negatively correlated with vitamin D levels (R = -0.39; P = .008).
Conclusions: In patients with breast cancer, high SIRI and PIV values may indicate the biological subtype of TNBC. In the HER2+ group, higher SII values were associated with low vitamin D concentrations and elevated BMI.
Keywords: body mass index; breast cancer; neoadjuvant chemotherapy; systemic inflammatory response indexes; vitamin D.
© The Author(s) 2025.