Fasting-mimicking diet: a metabolic approach for the treatment of breast cancer

Purpose of review Metabolic reprogramming is a new and potentially targetable hallmark of cancer. In recent years, fasting and fasting-mimicking diets (FMDs) have been tested as anticancer strategies both in preclinical experiments and in clinical trials. In this review, we aim at summarizing the available evidence about the antitumour activity of these approaches in preclinical breast cancer models, as well as results from clinical trials investigating fasting/FMD in breast cancer patients. Recent findings Preclinical evidence demonstrated that nutrient deprivation boosts the antitumor activity of chemotherapy, immunotherapy or targeted therapies in triple-negative breast cancer (TNBC) and HR+/HER2 models through both cell-autonomous antitumour effects in cancer cells and favourable modifications in intratumor immune cells. Several clinical experiences demonstrated that fasting/FMD is feasible and well tolerated in combination with standard treatments in BC patients, and that it could reduce chemotherapy-related toxicities. Finally, despite the absence of randomized trials demonstrating the antitumor activity of fasting/FMD in breast cancer patients, preliminary clinical reports suggest that this experimental nutritional strategy may enhance chemotherapy activity. Randomized clinical trials are ongoing to validate these results at a larger scale. Summary Fasting/FMD is a promising therapeutic approach in patients with breast cancer; ongoing and future trials will confirm their role in improving breast cancer care.