Calorie restriction in cancer patients undergoing chemotherapy: Facts, phantasy or misunderstanding

Experimental studies in cancer cell lines and tumour-bearing animals support the concept that a short-period fasting could potentiate the effect of antineoplastic chemotherapy due to a particular metabolic adaptation normal cells whereas cancer cells would remain particularly sensitive to the toxic effects of the therapy. The potential of such approach is actually emphasized by the media but data in humans are very scant and many oncologists fear that peri-chemotherapy fasting might worsen the patient nutritional status. The aim of this review is to focus on the benefits versus the adverse effects of the peri-chemotherapy fasting and to clarify if discrepancy of opinions regarding this approach relies on data from clinical trials or simply on misunderstandings or prejudices.We reviewed all the available literature regarding the peri-chemotherapy fasting in cancer patients with a special focus on compliance, adverse event prevalence and tumour response.Seven papers were available for the analysis. All studies included seemingly well-nourished patients and most of them had a breast or a gynaecologic cancer. Almost all concluded for the feasibility of the peri-chemotherapy fasting, with a good patient compliance. Weight loss was always reported but it was generally mild even if sometimes required a nutritional intervention between the cycles of chemotherapy. One RCT reported a better radiological response of the breast cancer at the neoadjuvant chemotherapy.Peri-chemotherapy fasting appears a safe procedure in well-nourished patients receiving a short-term chemotherapy. However claims of oncologic benefit are premature and rumors about its efficacy are presently unjustified.