LAUSR

Cancer immunotherapy using immune checkpoint blockers (ICBs) has revolutionized clinical oncology. In exceptional respond-ers, checkpoint inhibition enables long- term remission and potentially a cure, even in the metastatic setting, whereas there is still a significant proportion of patients without prolonged benefit. The complexity regulating the likelihood of ICB response can at least in part be explained by baseline variables such as tumor mutational burden, 1 immune checkpoint molecule expression levels (e.g., PD- 1/PD- L1) 2 and tumor T- cell infiltration. 3 Unfortunately, these factors cannot be deliberately modulated therapeuti-cally and therefore play only a minor role when envisioning treatment- enhancing strategies. Alternatively, emerging variables may easily be amenable to manipulation to optimize ICB response rates and durability. In this regard, nonpharmacological ap-proaches such as specific health interventions and treatment timing have recently gained momentum, proposing a more holistic framework for cancer immunotherapy and management within an interdisciplinary, cross- functional environment. Because diet influences the host microbiome, 4 which in turn affects ICB efficacy, 5,6 targeted dietary interventions represent a promising strategy to specifically modulate the microbial landscape and optimize cancer immunotherapy. 7 This concept is underscored by recent work in melanoma demonstrating an association of high fiber intake (i.e., ≥ 20 g/d) with improved progression- free survival under ICB therapy. 8 Mechanistically, a high- fiber diet promotes tumor T- cell infiltration as well as the expression of genes related to T- cell activation and effector function in murine models. 8 The concept of modulating ICB efficacy by dietary habits is further supported by prospective data from 101 patients with cancer on a fasting- mimicking diet (FMD) (NCT03340935). 9 The cyclic, 5- day dietary intervention was