The case of the best performing glioblastoma patient in the world and Frontiers in Nutrition

The case of the best performing glioblastoma patient in the world and Frontiers in Nutrition

The case of the best performing glioblastoma patient in the world and Frontiers in Nutrition

Dr. Csaba Tóth,  Dr. Zsófia Clemens


The case of the best performing glioblastoma patient in the world and Frontiers in Nutrition

It seems that “prestigious” medical journals are notoriously hindering reliable scientific medical information. This is, of course, nothing new and also applies to less prestigeous journals. Yet, still shocking when it comes to a cure of a deadly disease, namely glioblastoma. Here we tell the story in the form of questions and answers.


What kind of disease is glioblastoma?

Glioblastoma is one of, if not, the deadliest cancer type. Glioblastoma results in epileptic seizures, nausea, vomiting, trouble with walking, paralysis of the muscles, personality changes, problems with speaking and memory. In more advanced stages of the disease, it causes an inability to swallow, incontinence, somnolence, unstoppable epileptic seizures, coma, and ultimately death. This is the disease that took the life of John McKain, Edward Kennedy, and Beau Biden, son of the current American president. As shown by the so-called Kaplan-Meier curves, glioblastoma survival after 4 years is less than 3%. The below figure also shows the ”on the diet” survival and overall survival of our glioblastoma patient.

Figure: Our glioblastoma case vs. the Kaplan-Meier curve for survival

To what extent is glioblastoma affecting people?

There are 250,000 new cases in the world annually, and the numbers are increasing.


Why do you use an unconventional approach to treat glioblastoma when you are supposed to use the standard one?

Because we know from experience that the standard therapy (chemotherapy and radiotherapy) only worsens the outcome. We also know that the PKD (paleolithic ketogenic diet) gives the best chances to live as long as possible. As a physician, you took an oath (aka Hippocratic Oath) to strive for your patients’ recovery and life. The Hippocratic Oath is about the patient’s interest and not about following certain guidelines and standards.


What does recurrent glioblastoma mean?

“Reccurent” means that cancer has already been treated by standard modalities (surgery, chemotherapy, and radiotherapy), but despite all these “efforts” the disease recurred. 


What are the prospects with recurrent glioblastoma?

Somebody with a new glioblastoma diagnosis has six months to live on average. When we first met this patient it was already 8 months after his initial diagnosis. You can do the math about the prospects of this patient. 


What are the results you had with this patient?

The patient had remained progression-free, completely seizure-free, completely medication-free, and completely symptom-free. Currently, already for 4 and a half years.

Figure: MRI and CT scans performed during the course of the disease. 


What was the reaction from your colleagues when they learned about the unusual survival time of your patient?

  • You are going to kill this patient!
  • You are irresponsible! 
  • Don’t be too happy. The patient will die “in the end”.
  • This is a miracle from God
  • It is ok that the patient is still alive, but he cannot live without his antiepileptic medication
  • The initial diagnosis was wrong
  • The patient has a rare genetic feature that predisposed him to live that long despite glioblastoma


What reactions did you get from laypeople?

Mixed ones. More negative than positive ones. A lot of people were outraged and reacted in a highly offensive way. When we started the diet therapy with this patient back in 2016, we were the only ones saying that stopping eating plants is the way to go if you want to stay alive with glioblastoma or any other advanced cancer. Today’s carnivore influencers were nowhere at that time, so we were quite alone with our opinion. Some of these carnivore influencers were still following a vegetarian diet at this point. We were also the only ones telling the patients that chemotherapy and radiotherapy would shorten their lives. As a result, we received an immense amount of emotionally charged attacks.


Why did you want to publish in a scientific journal? Why is it not enough that you know you saved this patient?

Because we aim to help as many patients as possible. Publishing in a scientific journal is normally the way to introduce new scientific results in the field. This is how you disseminate your scientific result if you are a scientist. It is also the Health Law that tells you that publishing at scientific forums is the preferred way to make your results visible. Of course, nobody will pay you for the unique contribution that you want to share with others. On the contrary, you have to pay a large amount of money to get your article published. If you are not particularly wealthy, you may not be able to cover the publishing fee yourself. 


Where did you try to publish your results? 

We tried Frontiers in Nutrition.


Why did you pick Frontiers in Nutrition?

As the journal’s name implies, we thought that this journal is interested in publishing cutting-edge research. Also, because it is known as a low-carb friendly journal, we thought they would not immediately decline our manuscript with a knee-jerk reaction. An additional reason for picking Frontiers in Nutrition is because this journal was suggested by the author of the “other” case report that we will speak about later.


Did you publish your paper as a preprint beforehand?

Yes, we published the manuscript preprint at in 2019. To tell you the whole story, first also rejected publishing the manuscript, we guess, as a knee-jerk reaction. Since there was no formal reason to reject it, after some correspondence, they did post it.

Figure: Preprint


Why is it important to publish a paper as a preprint?

Because if you publish your manuscript as a preprint, then it becomes citable to other researchers.


Have you presented the case of this patient elsewhere?

Yes, we did present this case at several international conferences, including Italy, Germany, and the US.


What was the reaction at these conferences?

We tell you one typical story. In 2019, the Low Carb Denver Conference committee first declined the abstract of our poster, saying that it is highly “controversial” that the patient received no chemotherapy and radiotherapy. Later on, they did accept it.


What did you expect from Frontiers in Nutrition?

We expected that the publication process would be complicated, but we thought it would be fair.


Did you receive positive reviews from Frontiers in Nutrition reviewers?

The first reviewer said “everything is a limitation” then answered 13 times “no” to the 13 review questions. That was the whole review in this prestigious journal. The other review was correct. After this first round, the Editor decided to decline the manuscript based on the review’s suggestions. We decided to appeal the Editor’s decision and replied to the journal that that review may have included certain flaws and maliciousness, and we would appreciate another reviewer who can be fair. After this, a new Editor was appointed, and new reviewers were invited, altogether 4 more reviewers. Some of them were quite positive.


How long was the publication process at Frontiers in Nutrition?

It was 18 months long. It included two editors, six reviewers, and four rounds of resubmission. We were in the midst of preparing the 5th revision of the manuscript. We have to do so as one of the reviewers raised concerns about the diagnosis (at 14 months after initial submission!) and asked for additional histopathological exams from a sample that was more than 5 years old at this time. The reviewer specifically asked for checking for IDH mutation and MGMT methylation status. Considering all the associated legal aspects, this is a huge task because this necessitated obtaining a bunch of approvals from many parties. With all this amid the corona pandemic, we needed more time and asked for an extension of the deadline. Interesting things started to happen at this point.


What kind of interesting things happened?

Frontiers in Nutrition wrote that they are unwilling to extend the deadline because the review process has already been “too long”. After a few days, another interesting thing happened. Frontiers in Nutrition published a case study with a very long glioblastoma survival due to a ketogenic diet therapy. It was not our case report.


Was there anything else interesting with this paper?

Honestly, this alone was quite a shock. Moreover, there was no reference to our glioblastoma manuscript in this paper, even though our manuscript is formally citable as a preprint. 


Not that that’s not enough, but has there been anything else interesting?

Yes. We sent the case of our glioblastoma patient to one of the authors of this group in January 2018 (that is 3 and half years ago!). In an absolutely selfless way, we provided very specific information to this other group. Upon the request of this group, we sent original, yet unpublished data too. We genuinely thought that we should not withhold any crucial information from like-minded colleagues. Very soon after this, the first version of our glioblastoma manuscript was also sent to this group. The “other” case report not only did not reference our glioblastoma manuscript, but there was no reference to any of our previous case reports in the context of cancer. We also have a paper where we discussed the standard therapy vs. no standard therapy.

approach in cancer, which was a first of its kind that points to the likely adverse effects on cancer, based on direct clinical experience. Although the “other” case study also attributed long-term survival to not having chemo- and radiotherapy, the authors did not cite this paper either.


Has there been anything else as an “interesting” circumstance?

Yes, it was quite interesting to see that the last reviewer of our manuscript asked for checking for IDH status in our patient while the “other” case report was about a glioblastoma patient with IDH 1-mutant glioblastoma. This is an interesting coincidence that may raise the possibility of a conflict of interest. Of course, reviewers are anonymous, and we cannot be entirely sure about this. Anyway, the IDH status, in our opinion, is not at all a central issue, or we should rather say, is entirely irrelevant. Also, it is not too frequently discussed elsewhere as an attribute of glioblastoma.


Why do you think IDH status is irrelevant?

In our opinion, the IDH status and the other two molecular markers the reviewer asked for are irrelevant. In our experience, no matter what mutation the glioblastoma patient has, this will not affect the outcome of the diet therapy. It is only diet adherence and the presence/absence of other standard treatments that matter. Despite all these, we opted to do this additional histopathological exam to accommodate the reviewer, even if we knew this would significantly delay publication.



Why did the reviewer ask about the IDH status?

This was also about the correctness of the diagnosis. This reviewer also asked whether the histopathologist was independent from us. We assured the reviewer that the histopathologist who did the report was completely independent from us, as it was 8 months before we met the patient himself. We also replied that the diagnosis of glioblastoma, as stated in the histopathological report, was presented at the specialists’ consultation where all the attendant specialists of the hospital agreed with the diagnosis of glioblastoma (WHO grade IV). Apart from this, the review was very positive.


Why do you think Frontiers in Nutrition favored this glioblastoma manuscript over yours?

We don’t know. Our case report is superior over the “other” case as regards all relevant medical aspects. Our overwhelming experience is that journals massively sabotage researchers from Eastern-Europe and Russia.


Why do you think your glioblastoma case is superior to the “other” one?

First of all, our patient remained completely progression-free now already for 4 and a half years. At the same time, the “other” case, even if slowly, continuously progressed over the years.


In what other aspects is your case superior to the “other” case?

Our patient did not receive any other treatment after starting the diet therapy. The other patient underwent surgery because of tumor progression. Our patient did not have a single epileptic seizure in the last 4 and half years. The other patient did have seizures. Our patient did not receive antiepileptic or any other medicines. The other patient has been receiving antiepileptic and other medicines. Our patient is indeed “our” patient, meaning that we advised and followed him very closely and continuously, including several hundreds of email exchanges, phone and personal consultations during the 4 and half years. The “other” patient self-applied the diet without any professional guidance but relied on internet-based information of variable reliability, some of them not even qualifying as being scientific. The thing is that our patient is currently the best performing glioblastoma patient that ever received a dietary therapy in the world (but likely also the best performing one considered all other glioblastoma patients).


Your case report was reviewed for 18 months without a result. How long was the other case report reviewed?

The other paper took only 2 and half months to be published from submission.


Aren’t you happy about the result from the other case?

We are not happy with Frontiers in Nutrition very trickily delaying the publication of our manuscript for 1 and half years. This is 3 times the rest of your life if you are a glioblastoma patient. Given the annual number of new cases worldwide, this information theoretically could have affected 375,000 glioblastoma patients. What if it is your mother, wife or daughter the one who could have benefited out of these 375,000 patients? Of course, we are glad that there are other research groups on the same side, even if these groups are, as it turned out, “rival” research groups. It is ok if results, ideas, and methodologies compete with each other. But this should be done in an ethical and correct way. We think it is entirely unacceptable from a publisher or a journal to deceive and silence a research group and favor another.


Do you have any other glioblastoma patient who is that successful?

Yes, we do have many who are progression-free for a long time, not taking medications, and experience a high quality of life. Only in the last 12 months, we had more than 10 new glioblastoma patients. And many more with brain cancers of other types. Most of them are progression-free, medicine-free, and symptom-free. As you can imagine, with a dietary and non-standard therapy, the “human factor” is enormous. Therefore not all patients are adherent enough to the diet or the medical suggestions given to them, and not all patients are as successful as the patient from the case report.


Why did you go public about this issue?

The “other” case study was published “publicly”. Why shouldn’t we react publicly?


Are you going to publish about your other glioblastoma cases after all?

What would be your suggestion? 



  Journal Decision What did we do?
07.12.2019 Preprints   Submitted
09.12.2019   Declined without explanation Asked for explanation
10.12.2019   Answered that we did not upload one of the documents  
10.12.2019     We answered that we did upload the requested document
17.12.2019   Accepted the preprint  
26.12.2021 Frontiers in Nutrition   1st submission
      2 reviewers involved
05.02.2020   Rejected by the Editor  
14.03.2021     We raised concerns about serious “flaws” in the review process: one reviewer answered “no” 13 times, that was the review!
24.04.2020   New Editor was assigned and review started again with 2 new reviewers  
    Asked for revision We did the revision
17.09.2020     2nd submission
    Asked for revision Did the revisions
15.10.2020     3rd submission
    Asked for revision Did the revisions
11.02.2020     4th submission
    Asked for revision, reviewer questioned the diagnosis of the patient, and asked for additional histopathology. Started working on the revision including doing the new histopathology
      We asked for deadline extension because the scale of the requested extra work was impossible to finish in time
20.05.2020   Frontiers declined deadline extension because of the “delayed” state of the manuscript  
20.05.2020     We asked for considering deadline extension after all, because of the scale of the modifications asked by the reviewer
31.05.2021   Case study got accepted by Frontiers in Nutrition!!! The only “problem” that it was not ours, it was another glioblastoma case study but with a strikingly similar methodology. This case study took only 2.5 months to review! This case study included no reference to our study, even though the online preprint is citable.  
02.06.2021   Frontier in Nutrition wrote that we may complete the revision and submit the new version of the manuscript ???

Table: Overview of the 18-months review process at Frontiers in Nutrition


Dr. Zsófia Clemens and Dr. Csaba Tóth


How to cite:

Tóth, C.; Dabóczi, A.; Chanrai, M.; Schimmer, M.; Horváth, K.; Clemens, Z. 4-Year Long Progression-Free and Symptom-Free Survival of a Patient with Recurrent Glioblastoma Multiforme: A Case Report of the Paleolithic Ketogenic Diet (PKD) Used as a Stand-Alone Treatment After Failed Standard Oncotherapy. Preprints 2019, 2019120264 (doi: 10.20944/preprints201912.0264.v2).


4-year long progression-free and symptom-free survival of a patient with recurrent glioblastoma multiforme

4-year long progression-free and symptom-free survival of a patient with recurrent glioblastoma multiforme

4-year long progression-free and symptom-free survival of a patient with recurrent glioblastoma multiforme:

A case report of the Paleolithic Ketogenic Diet (PKD) used as a stand-alone treatment after failed standard oncotherapy

Csaba Tóth, Andrea Dabóczi, Madhvi Chanrai, Mária Schimmer, Katalin Horváth, Zsófia Clemens
4-year long progression-free and symptom-free survival of a patient with recurrent glioblastoma multiforme: A case report of the Paleolithic Ketogenic Diet (PKD) used as a stand-alone treatment after failed standard oncotherapy


Csaba Tóth1, Andrea Dabóczi1, Madhvi Chanrai2, Mária Schimmer1, Katalin Horváth3, Zsófia Clemens1*

1 International Center for Medical Nutritional Intervention – Paleomedicina Hungary Ltd., Budapest, Hungary

2 Independent researcher

3 County Hospital Zala, Zalaegerszeg, Department of Radiology and Radioisotope Diagnostics


*Corresponding author: Zsófia Clemens, PhD


Keywords: glioblastoma, brain tumor, paleolithic diet, ketogenic diet, paleolithic ketogenic diet, metabolic therapy, intestinal permeability, cancer treatment




Studies in animal models have suggested that the ketogenic diet may be effective in the treatment of cancer. However, human cohort studies on the ketogenic diet have, thus far, failed to show benefits in cancer survival or in any other hard clinical endpoints of the disease. This paper presents a case report of a patient with glioblastoma multiforme. The patient had initially been treated with standard oncotherapy including surgery, radiotherapy and chemotherapy. Despite standard treatment, the patient experienced a recurrence of the glioblastoma seven months later. Subsequently, the patient refused radiotherapy and chemotherapy and opted to use the paleolithic ketogenic diet (PKD) as a stand-alone therapy. Following the adoption of the PKD, progression of the disease has been completely halted. At the time of writing, the patient has remained in remission for 48 months, is without side-effects and experiences an excellent quality of life without the use of any drugs. 




In recent years there has been a surge of interest in the use of ketogenic diets as a potential treatment for cancer (Klement, 2017). The idea that ketogenic diets may have antitumor effects was initially put forward following the positive findings that emerged from animal studies (Zhou et al., 2007). Clinical studies with the ketogenic diet, have however, repeatedly failed to show benefits in any clinical hard endpoints such as progression-free survival and overall survival.

The authors of this paper have adopted an evolutionary approach to health and to the treatment of disease. Hence, we have developed and have been using the paleolithic ketogenic diet (PKD) in the treatment of several chronic diseases in more than 5000 patients for the last 10 years. The PKD is a diet that is based on animal fat and meat and is similar to the diet that was originally proposed by Voegtlin (1975). 


In the classic ketogenic diet, the source of the foods is not stipulated; whereas in the PKD the source of the fats and proteins is of the utmost importance. In practical terms this means that the PKD excludes all dairy products, cereal grains, plant oils, nightshades, legumes and dietary supplements; i.e. all foods that were not routinely available before the advent of agriculture 10,000 years ago.


The classic ketogenic diet (and its variants), typically contain unrestricted amounts of dairy products, nuts and plant oils, which are normally excluded in the PKD. In our opinion, this difference accounts for the additional benefits conferred by the PKD as compared to the classic ketogenic diet. We believe that excluding the non-PKD food components results in the normalization of intestinal permeability, which is a critical factor in the mechanism of action of the PKD in cancer (Tóth et al., 2017).


Thus far, we have published several case reports of patients who have been successfully treated with the PKD. These include: type 2 (Tóth and Clemens, 2015a) and type 1 diabetes (Tóth and Clemens, 2014; 2015b); Crohn’s disease (Tóth et al, 2016); Gilbert’s syndrome (Tóth and Clemens, 2015c); epilepsy (Clemens et al., 2013, 2015); complete reversal of cervical intraepithelial neoplasia (Tóth et al., 2018); halted progression of soft palate cancer (Tóth and Clemens, 2016) and regression of rectal cancer  ((Tóth and Clemens, 2017)


Here we present a case report of a patient with glioblastoma multiforme. Initially, the patient had been treated with standard oncotherapy including surgery, radiotherapy and chemotherapy. Despite standard treatment, the patient experienced a recurrence of the glioblastoma seven months later. Subsequently, the patient refused standard oncotherapy and opted to use the PKD as a stand-alone therapy. Since initiating the PKD, progression of the disease has been completely halted. At the time of writing, the patient has remained in remission for 4 years, and that too without the use of any drugs. Furthermore, besides being progression-free, the patient has also been symptom-free.




The medical history of the patient included bladder cancer operated in 2012. He also had hypertension treated with antihypertensives. The patient presented with severe headache in late January 2016 at the age of 52 years old. A subsequent MRI on the 28th of January 2016 showed a cystic lesion of 44 x 60 x 55 mm in the right parieto-temporo-occipital region with T2 hyperintensity, and edema resulting in a 10-mm midline shift at the level of the lateral ventricles (Fig. 1.). Histopathology showed polymorph cells, including giant and multi-nucleated cells as well as necrotic tissue. Immunohistochemistry showed GFAP positivity, Ki-67 labeling above 15% and significant p53 positivity suggesting glioblastoma multiforme.

Subtotal surgery was performed the next day. Histopathology indicated glioblastoma multiforme. A follow-up CT scan on 02 Mar 2016 showed a cystic mass of 49 x 29.9 mm containing another, 33 x 14 mm mass (Fig. 1.). Between March and May 2016 the patient underwent radiochemotherapy along with temozolomide treatment. An MRI in August 2016 showed tumor recurrence (Fig. 1.), whereupon the patient decided to stop standard treatment and contacted us for medical guidance.


Paleolithic ketogenic diet


In agreement with the patient, we started the PKD on the 2nd September 2016. The PKD is an animal fat-meat based diet with a fat:protein ratio of approximately 2:1 (in grams). The diet excludes cereal grains, dairy products, nightshades, legumes, plant oils (including coconut oil and olive oil), nuts, refined sugars, artificial sweeteners, food additives and all types of dietary supplements. Red and fatty meats were the predominant foods in the patient’s diet, with regular consumption of organ meat from cattle and pork as well. Although the PKD may include some plant foods in certain cases, in this patient’s case all plant foods were excluded in order to maximize the effectiveness of the PKD. The patient had two meals a day. He was suggested to eat when hungry, drink when thirsty, and to eat until satiation. The patient has been working full time during his entire follow-up. He was not doing any major exercise or workout. A sample daily menu is presented in Table 1.


Food items
Breakfast Braised calves liver: 150 g

Smoked slab from pork: 50 g

Dinner Pork shoulder steak: 150 g

Crispy fried bacon: 50 g


Table 1.

Sample daily menu on the paleolithic ketogenic diet. The patient typically eats twice a day. Meat, meat products are obtained from organic sources and are without additives.




The patient was under our close control with frequent personal visits, as well as e-mail and phone communication. 


Laboratory workup and urinary ketones


The patient was followed-up with regular laboratory workups and brain MRI. The patient occasionally checked urinary ketones for his own feedback but did not keep track of these data.


Oct 2016 Feb 2017 Aug 2017 Feb 2018 Aug 2018 Jan


Reference Unit
Glucose 6.6 4.6 5.4 4.1 5 4.9 3.4-6.1 mmol/L
Cholesterol 4.6 7.6 7 6.9 6.5 5.9 3.5-6.5 mmol/L
Triglyceride 0.76 1.51 0.94 0.78 0.7 0.8 0.55-1.85 mmol/L
HDL chol. 1.63 1.79 2.08 0.9-1.7 mmol/L
LDL chol. 2.82 5.51 4.73 <3.35 mmol/L
Uric acid 254 430 393 180-440 umol/L
TSH 3.97 3.64 0.4-4.5 mIU/L


Table 2.

Laboratory workup: metabolic parameters. The value that can be regarded as a positive outlier is indicated in red.


Oct 2016 Feb 2017 Aug 2017 Feb 2018 Aug 2018 Jan 2019 Reference Unit
Sodium 139 140 139 144 139 140 133-145 mmol/l
Potassium 3.8 4.9 5.7 3.6 4.3 4,1 3.5-5.5 mmol/l
Chloride 101 98 98 100 99 102 97-110 mmol/l
Calcium 2.33 2.3 2.36 2.47 2.39 2-2.6 mmol/l
Iron 12.8 14.8 13.2 16.9 14-30 µmol/l
Magnesium 0.9 0.99 1.02 0.84 0.78-1.03 mmol/l
Folic acid 36.8 20.7 14.2 37.4 2.4-45.4 nmol/l
Vit. B12 403 >738 505 349 142-725 pmol/l
Vit. D 84.2 50.4 62.7 54.5 >75 nmol/l


Table 3.

Laboratory workup: minerals, ions and vitamins. Values that can be regarded as negative outliers are indicated in blue.


Oct 2016 Feb 2017 Aug 2017 Jan 2018 Feb 2018 Jun 2018 Aug 2018 Jan 2019 Reference Unit
ESR 13 13 13 13 20 18 44 12 <15 mm/h
CRP 0.4 5.2 0.1 0-5 mg/l
Fibrinogen 4.25 1.76 3.41 2.05 2-4 g/l
TNF-alpha 5.9 1.6 6.09 6.85 1-12,4 pg/ml
IL-6 3 <2  4.8 0-3,4 pg/ml


Table 4.

Laboratory workup: inflammatory markers. Values that can be regarded as positive outliers are indicated in red.


Glucose levels were low except for the first measurement shortly after starting the diet. Cholesterol, HDL and LDL cholesterol tended to be slightly elevated. Triglyceride and uric acid were in the normal range (Table 2.). Mineral, ion and vitamin levels were also in the normal range except for the iron being slightly low on two measurements and vitamin D being low upon the last measurement (Table 3.). Inflammatory markers were generally low except for the ESR being elevated on three measurements (Table 4.). Blood work was used to give feedback to the patient on how to fine-tune the diet.   


Adherence level


The patient showed a generally high level of adherence throughout the entire follow-up. This was ascertained by blood work and feedback from the patient. Although the patient did not deviate from the major rules of the PKD he tended to overeat periodically. This may explain the TSH being closer to the upper limit of the normal range, which in our experience indicates relative overeating (Table 2.). The patient also reported having consumed coffee from time to time despite recommendations against drinking coffee. This was reflected in the slightly decreased iron levels; coffee consumption has a known effect of lowering iron (Morck et al., 1983).


MRI scans


During the follow-up of 48 months, nine consecutive MRI scans were performed 3-6 months apart. Each of them showed stable sizes of the tumor and the associated cyst (Figure 1.) except for the last three MRI which indicated a small but gradual decrease in the size of the cyst.

Figure 1.

MRI and CT scans performed during the course of the disease. Upper row: MRI showing the tumor with the associated cyst upon diagnosis; postoperative CT; 4-weeks postoperative CT; 5-months postoperative MRI.

Manual outline of the cystic tumor is in red. Manual outline of the edema is in yellow.

Middle row and bottom row: MRI scan one month before starting the PKD and nine consecutive follow-up MRI scans. Note that there is no change in the size of the tumor and the associated cyst across the first seven MRI scans, but there is a small but gradual decrease in the size of the cyst across the last three MRI scans. Red arrows indicate the cystic tumor while the yellow arrows indicate the edema.


General condition


Upon diet initiation the patient was mildly overweight (82 kg; 179 cm; BMI: 25.6). During the first six months of the diet he was continuously losing weight. In six months, he lost 10 kg (BMI: 22.5). Thereafter his weight fluctuated between 72 and 82 kg. The patient was free of symptoms attributable to the brain tumor during the entire follow-up. The patient did not experience epileptic seizures, nor any other neurological symptoms. The patient’s blood pressure normalized within one week of starting the diet. His antihypertensive medication was therefore stopped, and his blood pressure has remained normal without medication. The patient retained his physical strength and full work capacity during the entire follow-up. No side-effects of the diet were seen during the 4-year follow-up.


Intestinal permeability test (PEG400 challenge test)


Intestinal permeability was assessed using a polyethylene glycol (PEG 400) challenge test based on the method of Chadwick et al (1977). PEG 400 contains a mixture of inert water-soluble molecules of at least 11 different sizes. PEG 400 is also nontoxic, not degraded by intestinal bacteria, not metabolized by tissues, and rapidly excreted in urine. After a 3.0-gram oral dose of PEG, the subject makes a six-hour urine collection. Components were separated and quantified by high-performance liquid chromatography (HPLC). The percentage of each fraction of PEG excreted over 6 hours is calculated.


The PEG400 challenge test that was performed in January 2018 (at 17 months on the diet) showed normal intestinal permeability for each of the molecular sizes (Figure 2). This timing corresponded to a time period of not drinking coffee. 

Figure 2.

Result of the PEG400 challenge test. The test was done on 21 Jan 2018, at 17 months on the diet. This timing corresponds to a time period of not drinking coffee. Note that intestinal permeability was normal for all the molecular sizes.


Patient Consent

Written informed consent was obtained from the patient for publication of this case report.




Glioblastoma is the most aggressive form of brain tumor in adults with a prognosis of a median survival of 15 months after standard therapy (Thakkar et al., 2014). Currently, the standard of care for glioblastoma includes surgical debulking along with concurrent chemotherapy and radiotherapy. After diagnosis, our patient was also treated with temozolomide and concomitant radiotherapy, despite which a recurrence occurred after seven months. The patient then stopped using standard oncotherapy and started using the PKD as a stand-alone therapy. On this regime, the patient has been progression-free, symptom-free and medicine-free for 48 months.


We have to emphasize that the PKD that we use in the treatment of cancer patients differs from the classic version of the ketogenic diet that has traditionally been used in epilepsy (Kossoff and Rho, 2009) as well as in clinical trials with cancer patients (for a review, see: Klement et al., 2017). The main difference between the classic ketogenic diet (and its variants) and the PKD is that while the classic ketogenic diet is based on plant oils, dairy products and supplements, the PKD is based on animal meat, fat and organ meats. 


Despite the popularity of the ketogenic diet, clinical studies with the classic ketogenic diet repeatedly failed to provide evidence that it significantly improves cancer survival (Klement et al., 2017). For example, the ERGO trial, a prospective trial of the ketogenic diet in recurrent glioblastoma, failed to find a meaningful survival benefit (Rieger et al., 2014) while in another study with the ketogenic diet in glioblastoma (van der Louw et al., 2019) overall survival was only 12.8 months. 


Currently, there are only case studies that report on long-term survival benefit in cancer due to the ketogenic diet. One case study about two children with astrocytoma dates back to 1995 (Nebeling et al., 1995). Another study reported stable disease while the diet was sustained for seven months (Zuccoli et al., 2010). A recent study using the ketogenic diet along with drugs and hyperbaric oxygen therapy reported two-year survival in a glioblastoma patient (Elsakka et al., 20l8), while another one reported complete therapeutic response in a breast cancer patient (İyikesici et al., 2017). 


Previously, we have published three cancer case reports, where the PKD resulted in regression or stable disease. In a patient with recurrent cervical intraepithelial neoplasia, the PKD resulted in complete reversal (Tóth et al., 2018). In another patient with an aggressive soft palate cancer, the PKD resulted in progression-free status (Tóth and Clemens, 2016). The two patients are still progression-free at 49 and 59 months after diet onset. In the third patient with rectal cancer, the PKD resulted in a gradual regression while the PKD was highly adhered to (Tóth and Clemens, 2016). We have also reported on other cancer patients with progression-free survival beyond 2 years (Tóth et al., 2017; Clemens et al., 2019). These successful cases share the PKD as stand-alone therapy administered to the patients (Tóth et al., 2017; Clemens et al., 2019). 


In general, ketogenic diets are thought to convey an anticancer effect through targeting the Warburg phenomenon (Seyfried., 2012). Shifting away from a carbohydrate-based metabolism toward a fat-based one has been shown to slow down tumor growth in animal models although it has not been shown to stop cancer growth (Seyfried, 2012). 


As we have recently pointed out (Tóth et al., 2017), the general lack of efficacy of the classic ketogenic diet in cancer patients may be due to the fact that the classic ketogenic diet may not convey all the benefits that are associated with the PKD. 


Most importantly, a key beneficial mechanism of the PKD over other ketogenic diets is the normalization of intestinal permeability (Tóth et al., 2017). Besides the metabolic improvements, it may be this amelioration of intestinal permeability that is crucial to halting cancer progression. We have previously shown that it is the normalization of intestinal permeability rather than the shift to ketosis that is pivotal in the PKD treatment of Crohn’s disease and in autoimmune diseases (Tóth et al., 2017). In our experience, certain plant foods prevent complete normalization of intestinal permeability, which is why all plant foods were excluded from this patient’s diet.


In another patient with Hodgkin’s lymphoma, elevated intestinal permeability was shown to normalize after switching from the classic ketogenic diet to the PKD (Clemens and Tóth, 2019). 


Intestinal permeability is a membrane-related phenomenon that prevails at several levels of the organization of the body. Membrane permeability is crucial in defining cell-to-cell communication and in ensuring physiological contact inhibition within tissues. Loss of contact inhibition is known to be associated with a cancerous transformation of tissues (Kojima, 1993). Increased intestinal permeability has been suggested to promote tumorigenesis (Lin et al., 2012) and has been described as being associated with various tumor types (e.g. Soler et al 1999; Melichar, 2007). In 2016 we provided evidence that increased intestinal permeability normalized on the PKD in a Crohn’s disease patient in parallel with full recovery from the disease (Tóth et al., 2016). Yet, so far, no dietary or other interventions have resulted in the normalization of intestinal membrane permeability (Oldenwald and Turner, 2013).


Previous dietary intervention trials in cancer patients have not recognized the importance of the intestinal permeability. Also, attempts, until now, have failed to reverse elevated intestinal permeability. For example, a study with the regular paleolithic diet seemed to have no effect on intestinal permeability, nor did it decrease inflammation (Boers et al., 2014).


In cancer patients, a high level of inflammation is regarded as a negative predictor for survival (Strojnik et al., 2014). We put forward that normalizing intestinal permeability is key to controlling inflammation through the application of PKD. Accordingly, we generally see a decrease in the inflammatory markers after a shift toward the PKD (Tóth et al., 2018 and the referenced case studies with the PKD). In our glioblastoma patient, intestinal permeability, as measured by the PEG400 challenge test, also indicated normal intestinal permeability while on the PKD. In our patient, inflammatory markers were generally low, although they fluctuated to some degree during the follow-up. This fluctuation is likely to reflect periods of drinking coffee. The lowest level of the inflammatory markers was seen in the blood work from Jan 2019, a period corresponding to not drinking coffee. Inflammation level being elevated by coffee is indicated by the literature (Zampelas et a., 2004) and is also in accordance with our previous experience. 


We are not aware of published studies on intestinal permeability as regards the classical ketogenic diet. Yet, we assume that the classical ketogenic diet does not result in a normalization of the intestinal permeability. We opine that the exclusion of all non-PKD food items (dairy, vegetable oils and supplements which are typically found in the classical ketogenic diet) is a key to normalize intestinal permeability. This notion is supported by a previously published case where in a patient with Hodgkin’s lymphoma high intestinal permeability was reversed after shifting from the classical ketogenic diet to the PKD and stopping taking multiple supplements (Clemens and Tóth, 2019). 


Besides the fact that we used the PKD instead of the classic ketogenic diet, another important difference from previous studies is that we used the dietary therapy as a stand-alone treatment. Although it is generally believed that the standard care and dietary therapy can work in synergy (Woolf and Scheck, 2015), we believe that it is the absence of chemotherapy and radiotherapy which contributed to the unexpectedly long progression-free survival in our patient. 


Such an assumption agrees with the notion of Seyfried who pointed out that radiotherapy, chemotherapy and the use of steroids may hinder the effect of a metabolic therapy and paradoxically can result in boosting tumor growth through many different paths (Seyfried et al, 2010). Seyfried also raised the possibility that in the future metabolic therapies may become the standard of care in glioblastoma (Seyfried et al., 2019). We suggest that the predominance of chemotherapy and radiotherapy in current oncotherapy may also have prevented clinical trials of the ketogenic diet from major success. 


Publication Study type Patient number Diet type Overall survival Time to progression on the diet
Group studies Champ et al., 2014 Retrosp. 6 KD 4/6 patients alive at 12 months 5/6 patients progressed at 12 months
Rieger et al., 2014 Prosp. 17 KD Median survival 32 weeks; range: 6-86+ weeks All patients progressed. Median: 5 weeks; range: 3-13 weeks
van der Louw et al., 2019 Prosp. 9 KD Median survival 12.8 months; range 9.8-18 months Not reported
Woodhouse et al., 2019 Retrosp. 19 MAD 2-year survival 26.7% Not reported
Case studies Zuccoli et al., 2010 Case study 1 R-KD Not reported 10 months (stopped the diet at 7 months)
Schwartz et al., 2015 Case study 2 R-KD Not reported 1 and 3 months
Elsakka et al., 2018 Case study 1 KMT 24 months (at the time of writing the paper) No progression at 24 months 


Table 5.

Dietary intervention studies in glioblastoma multiforme. In the literature, the case with the longest progression-free survival to date is 24 months, as documented by Elsakka et al (2018) (24 months). 

KD: ketogenic diet; R-KD: restricted ketogenic diet; MAD: modified Atkins diet; KMT: ketogenic metabolic therapy


We put forward that the failure of previous ketogenic diet trials is not only down to the effect of radiotherapy and chemotherapy that elevate blood glucose levels, but also to the fact that chemotherapy (Keefe et al. 1997) and radiotherapy (Nejdfors et al., 2000) compromise the intestinal barrier and thereby may be counterproductive in cancer treatment.


Medium survival for glioblastoma patients without treatment is three months (Schapira, 2007). As far as we know, our patient is the first glioblastoma patient in the literature receiving a dietary therapy without any other treatment modalities (other than surgery). Currently, with his 48-months progression-free survival and 56 months overall survival (from diagnosis), he has the longest survival of all glioblastoma patients treated with a dietary therapy and published in the literature (Table 5.). 


Conflicts of Interest: The authors declare no conflict of interest.




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