# ERGO2: ketogenic diet and fasting during re-irradiation of recurrent glioma

Source: https://onco.cc/trials/ergo2/  
OnCo record `ergo2` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The only randomised trial of a ketogenic diet in brain tumours found no benefit. Patients could follow the diet and their ketone levels rose, but progression came just as quickly.

## Summary

50 patients were randomised 1:1. The intervention was feasible and safe: glucose fell and ketones rose as intended, and the diet was well tolerated over nine days. Progression-free survival at 6 months, the primary endpoint, did not differ (20% vs 16%; median PFS 3.2 vs 3.4 months), nor did overall survival (median 11.1 vs 10.5 months). The trial is small and the dietary exposure brief, so it cannot exclude a benefit from sustained ketosis; equally, longer feasibility studies (KETOCAN, modified Atkins with standard chemoradiation) show adherence declining by three months. Together they define the current state: ketogenic diets in glioma are feasible, unproven, and widely promoted to patients as if they were not.

## Fields

- Kind: Trial
- Status: negative
- Last checked: 2026-09-08
- Registry id: NCT01754350
- Phase: 2
- Setting: Recurrent glioblastoma and other malignant gliomas undergoing re-irradiation: 6-day calorie-restricted ketogenic diet plus 3-day fasting during radiotherapy vs standard diet
- Sponsor: Goethe University Frankfurt
- Enrolled: 50
- Result: 6-month PFS 20% vs 16%; median OS 11.1 vs 10.5 months; no benefit.
- Outcomes: Progression-free survival at 6 months: Ketogenic diet + fasting 20% vs Standard diet 16%
- Replication: No adequately powered trial exists. Feasibility studies concordant on tolerability, silent on efficacy.

## Sources

- ClinicalTrials.gov NCT01754350: https://clinicaltrials.gov/study/NCT01754350
- Voss et al. (Int J Radiat Oncol Biol Phys 2020): https://doi.org/10.1016/j.ijrobp.2020.06.021

## Connected records

- ideas: [One definitive ketogenic diet trial in glioblastoma, then stop](https://onco.cc/ideas/idea-nl-ketogenic-gbm-definitive-trial/)
- cancers: [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/)
- fronts: [Diet, Exercise & Lifestyle](https://onco.cc/fronts/nutrition-lifestyle/)
- technologies: [Ketogenic diets in glioblastoma](https://onco.cc/technologies/ketogenic-diet-glioblastoma/), [Metabolic therapy: starving the tumour of a nutrient](https://onco.cc/technologies/metabolic-therapy/)
- terms: [Metabolic theory of cancer: from Warburg to oncometabolites](https://onco.cc/terms/metabolic-theory-of-cancer/), [Progression-free survival (PFS)](https://onco.cc/terms/pfs/), [Warburg effect](https://onco.cc/terms/warburg-effect/), [Warburg-effect diet claims ('sugar feeds cancer')](https://onco.cc/terms/warburg-effect-diet-claims/)
- bottlenecks: [Failures are hidden](https://onco.cc/bottlenecks/b-negative-results/), [Misinformation and unproven therapies](https://onco.cc/bottlenecks/b-misinformation/)
- key papers: [ERGO2: A Prospective, Randomized Trial of Calorie-Restricted Ketogenic Diet and Fasting in Addition to Reirradiation for Malignant Glioma](https://onco.cc/key-papers/paper-voss-int-j-radiat-oncol-biol-phys/)
- roadmaps: [Diet, exercise and lifestyle roadmap: causes established → interventions that disappointed → exercise proven as treatment](https://onco.cc/roadmaps/nutrition-lifestyle-roadmap/)

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