# Unlocking the predictive value of post-neoadjuvant immune biomarkers in breast cancer: neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII)

## TL;DR

This study explores how immune biomarkers like NLR and SII after chemotherapy relate to breast cancer outcomes, finding some links to treatment response but not survival.

## Contribution

The study introduces post-neoadjuvant NLR and SII as potential predictors of pathological complete response in breast cancer.

## Key findings

- Post-neoadjuvant NLR and SII are independently associated with pathological complete response.
- Baseline NLR and SII correlate with patient characteristics like age and cancer subtype.
- Neither biomarker significantly impacts overall or progression-free survival.

## Abstract

To evaluate the potential prognostic value of two peripheral immune biomarkers—neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII)—in breast cancer patients treated with neoadjuvant chemotherapy, and to assess their association with pathological complete response (pCR) and other predictive factors. In addition, to determine whether prognostic or predictive differences exist between baseline and post-neoadjuvant values of these biomarkers.

We analyzed 801 women with early breast cancer treated with neoadjuvant chemotherapy, evaluating clinical and pathological data, survival outcomes, NLR (continuous and categorical) and SII.

Baseline NLR was significantly higher in younger patients, in those with positive pathological nodes, and in the HER2 + /HR − subtype, while baseline SII was elevated in the triple-negative subtype. Post-neoadjuvant chemotherapy (post-NCT) NLR and SII showed only weak associations with estrogen receptor expression, yet both were independently associated with pCR (post-NCT NLR: OR = 0.91; 95% CI: 0.84–0.98; p = 0.02; post-NCT SII: OR = 0.65; 95% CI: 0.47–0.89; p = 0.008). Neither biomarker showed a significant impact on overall or progression-free survival.

Post-treatment NLR and SII may reflect chemotherapy-induced immune changes and are associated with pathological complete response, but their additional predictive value is uncertain, and no prognostic impact was observed.

The online version contains supplementary material available at 10.1007/s10549-026-07928-2.