Impact of a ketogenic diet intervention during radiotherapy on body composition: I. Initial clinical experience with six prospectively studied patients

Abstract

Background: Based on promising preclinical data, ketogenic diets (KDs) have been proposed as supplementary measures for cancer patients undergoing standard-of-care therapy. However, data is still scarce on the tolerability and effects of KDs on cancer patients undergoing radiotherapy (RT). Here we present six cases of patients who underwent RT and concurrently consumed a self-administered KD in our clinic within a busy community hospital setting.

Methods: All patients were followed prospectively with measurements of blood parameters, quality of life and body weight and composition using bioelectrical impedance analysis.

Results: No adverse diet-related side effects occurred. Two patients had no elevated ketone body levels in serum despite self-reporting compliance to the diet. There was consensus that the KD was satiating and weight loss occurred in all patients, although this was only significant in two patients. Our data indicate that weight loss was mainly due to fat mass loss with concurrent preservation of muscle mass. Overall quality of life remained fairly stable, and all subjects reported feeling good on the diet. Tumor regression occurred as expected in five patients with early stage disease; however one subject with metastatic small cell lung cancer experienced slight progression during three cycles of combined chemotherapy + KD and progressed rapidly after ending the KD.

Conclusions: Our data lend support to the hypothesis that KDs administered as supportive measures during standard therapy are safe and might be helpful in preservation of muscle mass. Further studies with control groups are needed to confirm these findings and address questions regarding any putative anti-tumor effects. Based on the experience with these six cases we implemented further steps to improve issues with KD compliance and initiated a clinical study that is described in a companion paper.

Fig. 1

Body composition changes over the course of combined RT and KD. The symbols represent measured data in relation to the time on the KD, while the lines are drawn only for the duration of RT based on the linear regression fits with p values indicated for each fitted trend. Estimation of FM and ICW was unreliable for patients 2 and 4, so their data was omitted from the lower panels

Fig. 2

Similar to Fig. 1, but only for patient 5. Each panel includes a vertical line which indicates the transition from a KD to a low-CHO diet. Trends have only been computed and drawn for the time on the KD. The arrows indicate the start of 3 day chemotherapy cycles (Ch) with cisplatin/etoposide (C + E) or topotecan (Top), respectively. RT for a metastasis in the right humerus occurred between C + E cycles 2 and 3