Need for new review of article on ketogenic dietary regimes for cancer patients

Ketogenic diets consumed during radio-chemotherapy have beneficial effects on quality of life and metabolic health in patients with rectal cancer

PURPOSE

Interest in ketogenic diets (KDs) as complementary nutritional treatments for cancer patients is rising, although some skepticism about their safety exists. We, therefore, studied the effects of KDs on quality of life and blood parameters in rectal cancer patients undergoing radio-chemotherapy.

METHODS

EORTC-QLQ30 questionnaire scores and different metabolic and hormonal blood parameters were obtained prior to, in the middle of and at the end of radiotherapy within the KETOCOMP study (ClinicalTrials.gov Identifier: NCT02516501). A total of 18 patients consuming a KD were compared to 23 patients consuming their standard diet (SD). Baseline-end differences were measured using Wilcoxon tests, and repeated measures analysis was performed using linear mixed effects models.

RESULTS

Eighty-nine percent of patients on the KD reported subjectively feeling good or very good, but roughly half of them rated the daily routine implementation as difficult. Only the SD group experienced significant declines in physical and role functioning, while the KD group improved in role (p = 0.045), emotional (p = 0.018) and social functioning (p = 0.009).Urinary frequency, buttock pain and fatigue significantly increased in the SD group, but to a much lesser extent in the KD group. Several biomarkers of metabolic health (gamma-glutamyl-transpeptidase, triglyceride-glucose index, HDL cholesterol/triglyceride ratio, and free T3) improved in the KD, but not the SD group.

CONCLUSIONS

Despite being perceived as difficult to implement by ≈50% of patients, KDs are feasible as complementary therapies alongside radio-chemotherapy and associated with subjective well-being. The hypothesis that they exert beneficial effects on quality of life and metabolic health in rectal cancer patients is supported by our data.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02516501, registered Aug 6th 2015.

Ketogenic diet: a tool for the management of neuroendocrine neoplasms?

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms, whose incidence has rapidly increased in the last years. Nutrition plays an important role in their management; indeed, malnutrition negatively impacts on rates of complications, hospitalization, hospital stay, costs and mortality. Furthermore, it has been reported that a poor nutritional status could influence the outcome of patients with pancreatic NENs. Moreover, obesity, predisposing to insulin resistance and compensatory hyperinsulinemia, could stimulate the growth of these neoplasms. Ketogenic diet (KD), a high-fat, low-carbohydrate diet with adequate amounts of protein, has been reported to be a promising approach for the management of several types of cancer, mostly gynecological and neurological ones. Indeed, it appears to sensitize most cancers to standard treatment by exploiting the reprogramed metabolism of cancer cells and thus resulting in a promising candidate as an adjuvant cancer therapy. Thus, the aim of this review is to provide an overview on the importance of nutrition in cancer management and in particular in NENs' setting. Furthermore, we reported the current evidence on the efficacy of KD in the management of cancer and based on molecular mechanisms; we also hypothesize the potential use of this nutritional pattern in the management of NENs.

Ketogenic diets in medical oncology: a systematic review with focus on clinical outcomes

Preclinical data provide evidence for synergism between ketogenic diets (KDs) and other oncological therapies. The aim of this systematic review was to summarize data from clinical studies that have tested KDs along with other treatments used within medical oncology. The PubMed database was searched using the key words "ketogenic" AND ("cancer" OR "glioblastoma"). A secondary search was conducted by screening the reference lists of relevant articles on this topic. Relevant studies for this review were defined as studies in which KDs were used complementary to surgery, radio-, chemo-, or targeted therapy and at least one of the following four outcomes were reported: (i) Overall survival (OS); (ii) progression-free survival (PFS); (iii) local control rate; (iv) body composition changes. Twelve papers reporting on 13 clinical studies were identified. Nine studies were prospective and six had a control group, but only two were randomized. KD prescription varied widely between studies and was described only rudimentarily in most papers. Adverse events attributed to the diet were rare and only minor (grade 1-2) except for one possibly diet-related grade 4 event. Studies reporting body composition changes found beneficial effects of KDs in both overweight and frail patient populations. Beneficial effects of KDs on OS and/or PFS were found in four studies including one randomized controlled trial. Studies in high-grade glioma patients were not sufficiently powered to prove efficacy. Evidence for beneficial effects of KDs during cancer therapy is accumulating, but more high-quality studies are needed to assess the overall strength of evidence.

Beta-Hydroxybutyrate Promotes Proliferation, Migration and Stemness in a Subpopulation of 5FU Treated SW480 Cells: Evidence for Metabolic Plasticity in Colon Cancer

Background: Beta-hydroxybutyrate (BHB) as a ketone body is the metabolic fuel in oxidative phosphorylation pathway. So far the effects of BHB on the biology of tumor cells is contradictory. Therefore, we investigated the effect of BHB on viability, metabolism, proliferation and migration of 5FU treated SW480 colon cancer cell line. Methods: we treated the SW480 cells with IC50 dose of 5-fluorouracil (5FU) for 72 h to isolate a subpopulation of 5FU treated cells that were resistant to it. Effects of BHB on cell viability was investigated by MTT assay. Measurement of oxygen consumption rate (OCR) in parallel with extracellular acidification rate (ECAR) upon BHB treatment was used for determination of metabolic profile of these cells. Investigating the relationship between metabolic phenotype and the status of differentiation and stemness was done by analyzing the expression of PGC-1α, c-MYC, NANOG, ALPi and KRT20 genes by qRT-PCR. Clonogenic and scratch assay were performed to determine the proliferation and migration abilities of incubated with BHB compared to untreated cells. Results: BHB increased cell viability in SW480 and 5FU treated SW480 cells. The results showed a significantly decreased ECAR and increased OCR in both cell types following BHB treatment reflecting the superiority of oxidative phosphorylation profile compared to glycolysis in both cell types. Also, treatment with BHB increases the expression of genes normally associated with stemness and mitochondrial biogenesis and decreases the expression of genes related to glycolytic program and differentiation in 5FU treated cells. Self-renewal and migration potential of BHB treated cells increased significantly. Conclusion: These findings suggest that BHB utilization via oxidative mitochondrial metabolism can fuel proliferation, migration and stemness in 5FU treated SW480 colon cancer cells.

Application of Bayesian evidence synthesis to modelling the effect of ketogenic therapy on survival of high grade glioma patients

Background

Ketogenic therapy in the form of ketogenic diets or calorie restriction has been proposed as a metabolic treatment of high grade glioma (HGG) brain tumors based on mechanistic reasoning obtained mainly from animal experiments. Given the paucity of clinical studies of this relatively new approach, our goal is to extrapolate evidence from the greater number of animal studies and synthesize it with the available human data in order to estimate the expected effects of ketogenic therapy on survival in HGG patients. At the same time we are using this analysis as an example for demonstrating how Bayesianism can be applied in the spirit of a circular view of evidence.

Results

A Bayesian hierarchical model was developed. Data from three human cohort studies and 17 animal experiments were included to estimate the effects of four ketogenic interventions (calorie restriction/ketogenic diets as monotherapy/combination therapy) on the restricted mean survival time ratio in humans using various assumptions for the relationships between humans, rats and mice. The impact of different biological assumptions about the relevance of animal data for humans as well as external information based on mechanistic reasoning or case studies was evaluated by specifying appropriate priors. We provide statistical and philosophical arguments for why our approach is an improvement over existing (frequentist) methods for evidence synthesis as it is able to utilize evidence from a variety of sources. Depending on the prior assumptions, a 30–70% restricted mean survival time prolongation in HGG patients was predicted by the models. The highest probability of a benefit (> 90%) for all four ketogenic interventions was obtained when adopting an enthusiastic prior based on previous case reports together with assuming synergism between ketogenic therapies with other forms of treatment. Combinations with other treatments were generally found more effective than ketogenic monotherapy.

Conclusions

Combining evidence from both human and animal studies is statistically possible using a Bayesian approach. We found an overall survival-prolonging effect of ketogenic therapy in HGG patients. Our approach is best compatible with a circular instead of hierarchical view of evidence and easy to update once more data become available.

Electronic supplementary material

The online version of this article (10.1186/s12976-018-0084-y) contains supplementary material, which is available to authorized users.

Beta-hydroxybutyrate (3-OHB) can influence the energetic phenotype of breast cancer cells, but does not impact their proliferation and the response to chemotherapy or radiation

Background

Ketogenic diets (KDs) or short-term fasting are popular trends amongst supportive approaches for cancer patients. Beta-hydroxybutyrate (3-OHB) is the main physiological ketone body, whose concentration can reach plasma levels of 2–6 mM during KDs or fasting. The impact of 3-OHB on the biology of tumor cells described so far is contradictory. Therefore, we investigated the effect of a physiological concentration of 3 mM 3-OHB on metabolism, proliferation, and viability of breast cancer (BC) cells in vitro.

Methods

Seven different human BC cell lines (BT20, BT474, HBL100, MCF-7, MDA-MB 231, MDA-MB 468, and T47D) were cultured in medium with 5 mM glucose in the presence of 3 mM 3-OHB at mild hypoxia (5% oxygen) or normoxia (21% oxygen). Metabolic profiling was performed by quantification of the turnover of glucose, lactate, and 3-OHB and by Seahorse metabolic flux analysis. Expression of key enzymes of ketolysis as well as the main monocarboxylic acid transporter MCT2 and the glucose-transporter GLUT1 was analyzed by RT-qPCR and Western blotting. The effect of 3-OHB on short- and long-term cell proliferation as well as chemo- and radiosensitivity were also analyzed.

Results

3-OHB significantly changed the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in BT20 cells resulting in a more oxidative energetic phenotype. MCF-7 and MDA-MB 468 cells had increased ECAR only in response to 3-OHB, while the other three cell types remained uninfluenced. All cells expressed MCT2 and GLUT1, thus being able to uptake the metabolites. The consumption of 3-OHB was not strongly linked to mRNA overexpression of key enzymes of ketolysis and did not correlate with lactate production and glucose consumption. Neither 3-OHB nor acetoacetate did interfere with proliferation. Further, 3-OHB incubation did not modify the response of the tested BC cell lines to chemotherapy or radiation.

Conclusions

We found that a physiological level of 3-OHB can change the energetic profile of some BC cell lines. However, 3-OHB failed to influence different biologic processes in these cells, e.g., cell proliferation and the response to common breast cancer chemotherapy and radiotherapy. Thus, we have no evidence that 3-OHB generally influences the biology of breast cancer cells in vitro.

Electronic supplementary material

The online version of this article (10.1186/s40170-018-0180-9) contains supplementary material, which is available to authorized users.

Issues with data and analyses: Errors, underlying themes, and potential solutions

Some aspects of science, taken at the broadest level, are universal in empirical research. These include collecting, analyzing, and reporting data. In each of these aspects, errors can and do occur. In this work, we first discuss the importance of focusing on statistical and data errors to continually improve the practice of science. We then describe underlying themes of the types of errors and postulate contributing factors. To do so, we describe a case series of relatively severe data and statistical errors coupled with surveys of some types of errors to better characterize the magnitude, frequency, and trends. Having examined these errors, we then discuss the consequences of specific errors or classes of errors. Finally, given the extracted themes, we discuss methodological, cultural, and system-level approaches to reducing the frequency of commonly observed errors. These approaches will plausibly contribute to the self-critical, self-correcting, ever-evolving practice of science, and ultimately to furthering knowledge.

Beneficial effects of ketogenic diets for cancer patients: a realist review with focus on evidence and confirmation

Ketogenic diets (KDs) have gained popularity among patients and researchers alike due to their putative anti-tumor mechanisms. However, the question remains which conclusions can be drawn from the available human data thus far concerning the safety and efficacy of KDs for cancer patients. A realist review utilizing a matrix analytical approach was conducted according to the RAMESES publication standards. All available human studies were systematically analyzed and supplemented with results from animal studies. Evidence and confirmation were treated as separate concepts. In total, 29 animal and 24 human studies were included in the analysis. The majority of animal studies (72%) yielded evidence for an anti-tumor effect of KDs. Evidential support for such effects in humans was weak and limited to individual cases, but a probabilistic argument shows that the available data strengthen the belief in the anti-tumor effect hypothesis at least for some individuals. Evidence for pro-tumor effects was lacking completely. Feasibility of KDs for cancer patients has been shown in various contexts. The probability of achieving an anti-tumor effect seems greater than that of causing serious side effects when offering KDs to cancer patients. Future controlled trials would provide stronger evidence for or against the anti-tumor effect hypothesis.