Preclinical multi‐physiologic monitoring of immediate‐early responses to diverse treatment strategies in breast cancer by optoacoustic imaging

Optoacoustic imaging enables the measurement of tissue oxygen saturation (sO2) and blood perfusion while being utilized for detecting tumor microenvironments. Our aim was to employ multispectral optoacoustic tomography (MSOT) to assess immediate‐early changes of hemoglobin level and sO2 within breast tumors during diverse treatments. Mouse breast cancer models were allocated into four groups: control, everolimus (EVE), paclitaxel (PTX), and photodynamic therapy (PDT). Hemoglobin was quantified daily, as well as sO2 and blood perfusion were verified by immunohistochemical (IHC) staining. MSOT showed a temporal window of enhanced oxygenation and improved perfusion in EVE and PTX groups, while sO2 consistently remained below baseline in PDT. The same results were obtained for the IHC. Therefore, MSOT can monitor tumor hypoxia and indirectly reflect blood perfusion in a non‐invasive and non‐labeled way, which has the potential to monitor breast cancer progression early and enable individualized treatment in clinical practice. MSOT was used to assess immediate‐early changes in hemoglobin levels and oxygen saturation during different treatments. Optoacoustic imaging holds promise as a non‐invasive and non‐labeled technique for monitoring breast cancer progression early and evaluating efficacy.