Since the initial observations by Warburg in 1924, it has become clear in recent years that tumour cells require a high level of glucose to proliferate. Therefore, a ketogenic diet that provides the body with energy mainly through fat and proteins, but contains a reduced amount of carbohydrates, has become a dietary option for supporting tumour treatment and has exhibited promising results. In the present study, the first case series of such a treatment in general practice is presented, in which 78 patients with tumours were treated within a time window of 10 months. The patients were monitored regarding their levels of transketolase-like-1 (TKTL1), a novel tumour marker associated with aerobic glycolysis of tumour cells, and the patients' degree of adherence to a ketogenic diet. Tumour progression was documented according to oncologists' reports. Tumour status was correlated with TKTL1 expression (Kruskal-Wallis test, P<0.0001), indicating that more progressed and aggressive tumours may require a higher level of aerobic glycolysis. In palliative patients, a clear trend was observed in patients who adhered strictly to a ketogenic diet, with one patient experiencing a stagnation in tumour progression and others an improvement in their condition. The adoption of a ketogenic diet was also observed to affect the levels of TKTL1 in those patients. In conclusion, the results from the present case series in general practice suggest that it may be beneficial to advise tumour patients to adopt a ketogenic diet, and that those who adhere to it may have positive results from this type of diet. Thus, the use of a ketogenic diet as a complementary treatment to tumour therapy must be further studied in rigorously controlled trials.
Keywords: TKTL1; aerobic glycolysis; cancer; case series; diet; ketogenic diet.