Decline of Lactate in Tumor Tissue After Ketogenic Diet: In Vivo Microdialysis Study in Patients with Head and Neck Cancer

In head and neck squamous cell carcinoma (HNSCC) aerobic glycolysis is the key feature for energy supply of the tumor. Quantitative microdialysis (D) offers an online method to measure parameters of the carbohydrate metabolism in vivo. The aim was to standardize a quantitative D-study in patients with HNSCC and to prove if a ketogenic diet would differently influence the carbohydrate metabolism of the tumor tissue. Commercially available 100kDa-CMA71-D- catheters were implanted in tumor-free and in tumor tissue in patients with HNSCC for simultaneous measurements up to 5days. The metabolic pattern and circadian rhythm of urea, glucose, lactate, and pyruvate was monitored during 24h of western diet and subsequent up to 4days of ketogenic diet. After 3days of ketogenic diet the mean lactate concentration declines to a greater extent in the tumor tissue than in the tumor-free mucosa, whereas the mean glucose and pyruvate concentrations rise. The in vivo glucose metabolism of the tumor tissue is clearly influenced by nutrition. The decline of mean lactate concentration in the tumor tissue after ketogenic diet supports the hypothesis that HNSCC tumor cells might use lactate as fuel for oxidative glucose metabolism.