The impact of ketogenic diet and psychological factors on tumor shrinkage in breast cancer patients receiving neoadjuvant chemotherapy: A prospective clinical trial.

e23287 Background: The response to neoadjuvant chemotherapy (NAC) in breast cancer (BC) is influenced by metabolic and psychosocial factors. Although ketogenic diets (KD) are thought to increase chemotherapy sensitivity, the predictive value of quality of life (QoL) on pathological response remains unclear. This study investigated the impact of KD intervention and QOL (particularly anxiety and emotional functioning) on tumor shrinkage in patients with BC receiving NAC. Methods: The study included overweight and obese women (aged 19–64 years) diagnosed with BC who were scheduled to receive NAC. All patients received NAC containing anthracycline and taxane as a standard procedure. After anthracycline treatment, patients (n:38) were randomly divided into two group (1:1): the first group (n:19) received KD, and the second group (n:19) received healthy diet. Patients were evaluated before treatment (T0), after anthracycline treatment (T1), and after taxane treatment (T2). Waist to hip ratio and body fat percent were measured. Serum biomarkers, including glucose, insulin, HOMA-IR, and oxidative stress indices (TAC/TOS), were analysis. The QOL was assessed using EORTC QLQ-C30 and EORTC QLQ-BR23. The data were evaluated using the SPSS 22 statistical package program. Predictors of tumor response were identified using univariate regression, followed by two multivariate models: Model 1 (baseline factors only) and Model 2 (baseline and dynamic change factors). Results: Ketogenic diet use did not significantly predict tumor shrinkage (β = -0.06, t = -0.38, p = 0.704). In a multivariate regression model focusing on baseline factors, future anxiety was the only independent predictor of the of tumor shrinkage (β = -0.32, t = -2.05, p = 0.048), where higher anxiety was associated with reduced treatment benefit. When baseline (T0) and dynamic factors (change between T0 and T2) were analyzed together, the only independently significant predictor of tumor shrinkage was the change in emotional functioning (β = 0.39, t = 2.51, p = 0.017). Improvements in emotional functioning over time were positively correlated with greater tumor regression. Other factors, including waist to hip ratio, body fat percents, serum biomarkers, showed no significant association with response in multivariate models. Conclusions: While KD did not directly influence the magnitude of tumor shrinkage in this study, psychological and emotional factors emerged as significant independent predictors of treatment response. The negative impact of future anxiety and the benefit of improved emotional functioning suggest that providing support to improve QOL during treatment may be beneficial in terms of treatment response for BC patients receiving NAC. Clinical trial information: NCT05234502 .