Current guidelines for nutrition therapy in cancer: The arrival of a long journey or the starting point?

Large epidemiological data reveal that cancer is progressively becoming a chronic and disabling disease. Implementation in daily practice of early therapies aiming at addressing patients' needs is imperative. Nutrition is a major determinant of patients' quality of life, yet it is frequently neglected. Hopefully, reverting this skeptical clinical approach to nutrition, clinical practice guidelines of nutrition care in patients with cancer have been developed and published by international oncology and nutrition societies. By analyzing the more recent guidelines, it appears that a number of issues may contribute to their insufficient implementation in daily practice. Among them are heterogeneity of recommendations across different guidelines and insufficient robustness of evidence, as well as questionable generalization of recommendations. Future guidelines should aim at providing tumor-specific recommendations for the whole clinical journey of patients with cancer. Also, new, interesting areas should be covered, including fasting metabolism and circadian rhythmicity.