Metabolomic signatures of long-term risk of breast and prostate cancers and diet in the SU.VI.MAX cohort : New insights from metabolomics applied to nutritional epidemiology

Les cancers du sein et de la prostate sont parmi les cancers ayant la plus forte incidence dans le monde,notamment dans les pays occidentaux. Les principaux défis actuels sont d’améliorer la compréhension des relations nutrition/santé et l’identification des personnes à plus haut risque bien avant l’apparition du cancer afin de mettre en place des actions de préventions. De nombreux facteurs influencent la mise en place et la progression du cancer. Parmi eux, la nutrition apparaît comme un facteur clé, puisqu’il s’agit d’un facteur modifiable sur lequel il est possible d'agir via des interventions, il est donc essentiel d’évaluer sa contribution. Pour cela, une mesure précise de l'apport nutritionnel est nécessaire. La métabolomique permettant l’identification de potentiels biomarqueurs endogènes, exogènes et microbiens ouvre donc de nouvelles perspectives en épidémiologie nutritionnelle. A ce jour, encore très peu d’études ont investigué l’impact de l’alimentation globale sur le métabolisme et le risque de cancer du sein et de la prostate par profilage métabolomique. Dans le cadre de cette thèse, nous avons donc conduit des études cas-témoins nichées et transversales dans la cohorte SU.VI.MAX afin de mettre en évidence des signatures plasmatiques du risque de cancers du sein et de la prostate et de l’alimentation globale. Les échantillons plasmatiques ont été collectés à l’inclusion dans la cohorte et analysés par deux méthodes complémentaires : la spectrométrie de masse couplée à la chromatographie liquide et la résonance magnétique nucléaire du proton. Les habitudes alimentaires des participants ont été estimées grâce à des enregistrements alimentaires de 24h répétés et les données socio-démographiques et de mode de vie ont été obtenues grâce à des questionnaires autodéclarés. Ces recherches ont permis de mettre en évidence des métabolites endogènes et issus du métabolisme microbien associés à l’alimentation globale et également des biomarqueurs candidats d’une exposition alimentaire spécifique. Nous avons également identifié des métabolites associés au risque de cancers du sein et de la prostate, endogènes, exogènes et microbiens suggérant une perturbation métabolique jusqu’à 13 ans avant le diagnostic du cancer. Par ailleurs, l’alimentation semble jouer un rôle dans la variation des taux plasmatiques de certains métabolites permettant de discriminer les individus à plus haut risque de développer un cancer du sein ou de la prostate. Ces résultats devront être répliqués dans d’autres études indépendantes d’observation et d’intervention.A terme, l’identification de signatures métaboliques robustes du risque de cancers du sein et de la prostate, de l’impact de l’alimentation sur le métabolisme et la cancérogenèse et de l’apport alimentaire pourraient permettre de contribuer à l’amélioration de la compréhension des relations entre environnement et santé, de l’évaluation de l’exposition nutritionnelle voire à la mise en place de nouvelles recommandations en matière de santé publique en vue de la diminution de l’incidence de ces pathologies.Breast and prostate cancers are among the cancers with the highest incidence worldwide and notably in Western countries. The main current challenges lie in the improvement of understanding of nutrition/health relationships and in the identification of individuals at higher risk long before the development of overt cancer to set up prevention actions. A variety of factors exert an impact on the onset and progression of cancer. Among these, nutrition appears as a key factor, in that it can be modified and acted upon through interventions. It is therefore crucial to assess its contribution. For this purpose,detailed and accurate assessment of nutritional intake is essential. Metabolomics, allowing the identification of endogenous, exogenous and microbial biomarkers, opens new perspectives in nutritional epidemiology. So far, few have studies investigated the impact of overall diet on metabolism and risk of breast and prostate cancer through metabolomic profiling. As part of this thesis, we conducted nested case-controls and cross-sectional studies within the SU.VI.MAX cohort to highlight plasma signatures of breast and prostate cancer risks and of overall diet. Plasma samples were collected at baseline and were analysed using two complementary methods : mass spectrometry coupled with liquid chromatography and proton nuclear magnetic resonance. Participants dietary habits were estimated using repeated 24h dietary records and socio-demographic and lifestyle data were collected from self-administered questionnaires.These investigations highlighted endogenous and microbial metabolites associated with overall diet as well as candidate biomarkers of specific dietary exposures. We also identified endogenous, exogenous and microbial metabolites associated with breast and prostate cancers risk suggesting a metabolic disruption up to 13 years before cancer diagnostic. Furthermore, diet appears to be implicated in the variation in plasma levels of some metabolites discriminating individuals at higher risk of developing breast or prostate cancers. These results need to be replicated in future independent observational and interventional studies. In the future, the identification of robust metabolic signatures of breast and prostate cancers risk, of the impact of diet on metabolism and carcinogenesis, and food intake would contribute to better understand health and environment relationships, to better estimate nutritional exposure or even to contribute to the set-up of new public health recommendations in order to reduce the incidence of these pathologies

Signatures métabolomiques associées au risque à long terme de cancers du sein et de la prostate et à l’alimentation dans la cohorte SU.VI.MAX : Nouveaux horizons ouverts par la métabolomique appliquée à l’épidémiologie nutritionnelle

Breast and prostate cancers are among the cancers with the highest incidence worldwide and notably in Western countries. The main current challenges lie in the improvement of understanding of nutrition/health relationships and in the identification of individuals at higher risk long before the development of overt cancer to set up prevention actions. A variety of factors exert an impact on the onset and progression of cancer. Among these, nutrition appears as a key factor, in that it can be modified and acted upon through interventions. It is therefore crucial to assess its contribution. For this purpose,detailed and accurate assessment of nutritional intake is essential. Metabolomics, allowing the identification of endogenous, exogenous and microbial biomarkers, opens new perspectives in nutritional epidemiology. So far, few have studies investigated the impact of overall diet on metabolism and risk of breast and prostate cancer through metabolomic profiling. As part of this thesis, we conducted nested case-controls and cross-sectional studies within the SU.VI.MAX cohort to highlight plasma signatures of breast and prostate cancer risks and of overall diet. Plasma samples were collected at baseline and were analysed using two complementary methods : mass spectrometry coupled with liquid chromatography and proton nuclear magnetic resonance. Participants dietary habits were estimated using repeated 24h dietary records and socio-demographic and lifestyle data were collected from self-administered questionnaires.These investigations highlighted endogenous and microbial metabolites associated with overall diet as well as candidate biomarkers of specific dietary exposures. We also identified endogenous, exogenous and microbial metabolites associated with breast and prostate cancers risk suggesting a metabolic disruption up to 13 years before cancer diagnostic. Furthermore, diet appears to be implicated in the variation in plasma levels of some metabolites discriminating individuals at higher risk of developing breast or prostate cancers. These results need to be replicated in future independent observational and interventional studies. In the future, the identification of robust metabolic signatures of breast and prostate cancers risk, of the impact of diet on metabolism and carcinogenesis, and food intake would contribute to better understand health and environment relationships, to better estimate nutritional exposure or even to contribute to the set-up of new public health recommendations in order to reduce the incidence of these pathologies.Les cancers du sein et de la prostate sont parmi les cancers ayant la plus forte incidence dans le monde,notamment dans les pays occidentaux. Les principaux défis actuels sont d’améliorer la compréhension des relations nutrition/santé et l’identification des personnes à plus haut risque bien avant l’apparition du cancer afin de mettre en place des actions de préventions. De nombreux facteurs influencent la mise en place et la progression du cancer. Parmi eux, la nutrition apparaît comme un facteur clé, puisqu’il s’agit d’un facteur modifiable sur lequel il est possible d'agir via des interventions, il est donc essentiel d’évaluer sa contribution. Pour cela, une mesure précise de l'apport nutritionnel est nécessaire. La métabolomique permettant l’identification de potentiels biomarqueurs endogènes, exogènes et microbiens ouvre donc de nouvelles perspectives en épidémiologie nutritionnelle. A ce jour, encore très peu d’études ont investigué l’impact de l’alimentation globale sur le métabolisme et le risque de cancer du sein et de la prostate par profilage métabolomique. Dans le cadre de cette thèse, nous avons donc conduit des études cas-témoins nichées et transversales dans la cohorte SU.VI.MAX afin de mettre en évidence des signatures plasmatiques du risque de cancers du sein et de la prostate et de l’alimentation globale. Les échantillons plasmatiques ont été collectés à l’inclusion dans la cohorte et analysés par deux méthodes complémentaires : la spectrométrie de masse couplée à la chromatographie liquide et la résonance magnétique nucléaire du proton. Les habitudes alimentaires des participants ont été estimées grâce à des enregistrements alimentaires de 24h répétés et les données socio-démographiques et de mode de vie ont été obtenues grâce à des questionnaires autodéclarés. Ces recherches ont permis de mettre en évidence des métabolites endogènes et issus du métabolisme microbien associés à l’alimentation globale et également des biomarqueurs candidats d’une exposition alimentaire spécifique. Nous avons également identifié des métabolites associés au risque de cancers du sein et de la prostate, endogènes, exogènes et microbiens suggérant une perturbation métabolique jusqu’à 13 ans avant le diagnostic du cancer. Par ailleurs, l’alimentation semble jouer un rôle dans la variation des taux plasmatiques de certains métabolites permettant de discriminer les individus à plus haut risque de développer un cancer du sein ou de la prostate. Ces résultats devront être répliqués dans d’autres études indépendantes d’observation et d’intervention.A terme, l’identification de signatures métaboliques robustes du risque de cancers du sein et de la prostate, de l’impact de l’alimentation sur le métabolisme et la cancérogenèse et de l’apport alimentaire pourraient permettre de contribuer à l’amélioration de la compréhension des relations entre environnement et santé, de l’évaluation de l’exposition nutritionnelle voire à la mise en place de nouvelles recommandations en matière de santé publique en vue de la diminution de l’incidence de ces pathologies

Plasma metabolomic signatures associated with long-term breast cancer risk in the SU.VI.MAX prospective cohort.

International audienceBackground: Breast cancer is a major cause of death in occidental women. Mechanisms involved in its etiology remain misunderstood. Metabolomics is a powerful tool which may help elucidating novel biological pathways and identify new biomarkers in order to predict breast cancer well before symptoms appear. The aim of this project was to investigate whether untargeted metabolomic signatures from blood draws of healthy women could contribute to better understand and predict the long-term risk of developing breast cancer. Methods: A nested case-control study was conducted within the SU.VI.MAX prospective cohort (13 years of follow-up) to analyze baseline plasma samples of 211 incident breast cancer cases and one or two matched controls by case using LC-MS mass spectrometry and NMR. Multivariable conditional logistic regression models were computed. Results: Several metabolites were associated with breast cancer risk. Notably, we observed that lower plasma levels of O-succinyl-homoserine (microbial metabolite), lipoproteins, lipids, glycoproteins, acetone, glycerol-derived compounds and unsaturated lipids and higher plasma levels of valine/norvaline, glutamine/isoglutamine, lysine, arginine, creatine, creatinine, 5-aminovaleric acid, phenylalanine, tryptophan, γ-glutamyl-threonine, ATBC (acetyltributylcitrate – a plasticizer contaminant), 2-amino-cyanobutanoic acid (microbial metabolite), pregnene-triol sulfate, and glucose were associated with an increased risk of developing breast cancer during follow-up. Conclusions: Several pre-diagnostic plasmatic metabolites are strongly associated with long-term breast cancer risk. If confirmed in other independent cohort studies, these results could help to identify healthy women at higher risk of developing breast cancer in the subsequent decade and to propose a better understanding of the complex mechanisms involved in its etiology. We are studying the role of diet (a modifiable risk factor) on metabolism and breast cancer etiology using notably penalized regression methods (LASSO, Elastic Net) which could help to improve personalized prevention strategies

NMR metabolomic analysis of breast cancer risk in the SU.VI.MAX prospective cohort study

International audienceBackground: Application of metabolomics to the field of nutritional epidemiology opens new perspectives for ground-breaking discoveries. To our knowledge, no prospective study had been conducted to investigate the relationship between baseline non-targeted metabolomics profiles and subsequent long-term breast cancer risk. This project investigates whether metabolomic signatures, established from a simple blood draw, could contribute to better understand and predict the risk of developing female breast cancer in the following decade.Methods: A nested case-control study was set up in the SU.VI.MAX cohort (1994-2007), involving 206 breast cancer cases and 396 matched controls. Non-targeted NMR metabolomic profiles were assessed on baseline plasma samples. Multivariable conditional logistic regression models were used. Predictive performance was assessed using the NRI indicator (Net Reclassification Improvement). Results: For the NOESY sequence, 237 buckets were obtained after NMR spectrum division with “intelligent bucketing”, among which 25 were significantly associated with breast cancer risk in logistic models (228/27 buckets for the CPMG sequence, respectively). The corresponding P-values ranged from 0.00007 (for the bucket 5.1869 ppm, corresponding to methine moieties of glyceryl, ORT3vsT1=0.37 [0.23-0.61]) to 0.04 (for the bucket 2.429 ppm, corresponding to glutamine, ORT3vsT1=1.62 [1.02-2.57]). Lipoproteins, lipids (including unsaturated fatty acids, glycerides and glycerophospholipids and derived compounds) and glycoproteins were associated with decreased breast cancer risk, whereas several amino acids and derived compounds (valine, leucine, glutamine, creatine, creatinine and threonine) and beta-glucose were associated with increased risk. Most metabolites significantly improved the predictive performance of the models.Conclusion: This pioneering study suggests that several metabolites (some of which pertaining to the food metabolome) would be involved in breast cancer etiology. Similar analyses based on mass spectrometry metabolomics are underway in the study, as well as the assessment of the correlations between metabolomic profiles and detailed food and nutrient intakes

Apports alimentaires, via les compléments alimentaires et totaux en antioxydants et risque de cancers digestifs dans la cohorte prospective NutriNet-Santé

Introduction et but de l’étude De nombreuses études expérimentales ont montré un effet bénéfique des antioxydants dans la prévention des cancers digestifs. Toutefois, les études épidémiologiques restent contrastées. En outre, relativement peu disposent des doses d’apport incluant une mesure quantitative de la consommation via les compléments alimentaires. L’objectif était d’étudier les associations entre les apports en vitamines C et E, bêta-carotène et sélénium (alimentaires, via les compléments alimentaires et totaux) et le risque de cancers digestifs, ainsi qu’une potentielle modulation par l’apport en alcool et le statut tabagique. Matériel et méthodes Cette étude prospective incluait 38 812 sujets âgés de 45 ans et plus, de la cohorte NutriNet-Santé. Cent-soixante-sept cas de cancers digestifs incidents (120 côlon-rectum, 26 pancréas, neuf oesophages, sept estomacs et cinq foies) ont été diagnostiqués entre 2009 et 2016. Les données alimentaires étaient recueillies par des enregistrements de 24h répétés. Un questionnaire spécifique estimait la consommation de compléments alimentaires sur une période de 12 mois. Une base de données de composition contenant 8000 compléments a été développée. Les associations entre apports en antioxydants et risque de cancers digestifs ont été caractérisées par des modèles de Cox multivariés. Résultats et Analyse statistique Les apports en vitamine C alimentaires (HRQ4 contre Q1=0,55 (0,34–0,91), p-tendance=0,01) et totaux (HRQ4 contre Q1=0,51 (0,30–0,84), p-tendance=0,008) étaient associés à une diminution du risque de cancers digestifs, de même pour les apports en vitamine E alimentaires (HRQ4 contre Q1=0,56 (0,34–0,92), p-tendance=0,005) et totaux (HRQ4 contre.Q1=0,58 (0,36–0,94), ptendance=0,003) et les apports en sélénium alimentaires (HRper 1-unit increment=0,99 (0,98-1,00), p=0,04) et totaux (HRper 1-unit increment=0,99 (0,98–1,00), p=0,03). Des interactions significatives entre les apports alimentaires et totaux en sélénium et l’apport en alcool, et entre l’apport total en vitamine E et le statut tabagique ont été observées. Conclusion Cette large étude prospective, incluant une évaluation quantitative des apports via les compléments alimentaires, suggère un possible effet protecteur des antioxydants (vitaminesC et E et sélénium) sur le risque de cancers digestifs. Elle suggère également une modulation de certaines de ces relations par la consommation d’alcool et le statut tabagique

Apports en vitamines du groupe B et risque de cancer du sein : résultats de la cohorte prospective NutriNet-Santé

National audienceIntroduction et but de l’étude Des études expérimentales ont suggéré un effet protecteur des vitamines B vis-à-vis du cancer du sein, potentiellement modulé par l’apport en alcool. Cependant, les études épidémiologiques sont limitées, en particulier concernant les vitamines du groupe B hors folates. En outre, relativement peu d’études disposent des doses d’apport incluant une mesure quantitative de la consommation via les compléments alimentaires. L’objectif était d’étudier les associations entre les apports en vitamines B (alimentaires, via les compléments alimentaires et totaux) et le risque de cancer du sein, ainsi qu’une potentielle modulation par l’apport en alcool. Matériel et méthodes Cette étude prospective incluait 27 853 femmes âgées de 45 ans et plus, de la cohorte NutriNet-Santé. Quatre cent soixante-trois cas de cancer du sein incidents ont été diagnostiqués entre 2009 et 2016. Les données alimentaires étaient recueillies par des enregistrements de 24h répétés. Un questionnaire spécifique estimait la consommation de compléments alimentaires sur une période de 12 mois. Une base de données de composition contenant 8000 compléments a été développée. Les associations entre apports en vitamines B et risque de cancer du sein ont été caractérisées par des modèles de Cox multivariés. Résultats Les apports en vitamine B6 alimentaires (HRQ4 contre Q1=0,73 (0,54–0,99), p-tendance=0,04), via les compléments alimentaires (HRQ4 contre Q1=0,61 (0,38–0,99), ptendance=0,05) et totaux (HRQ4 contre Q1=0,67 (0,50–0,90), ptendance=0,01) étaient inversement associés au risque de cancer du sein. L’apport total en vitamine B1 était inversement associé au risque de cancer du sein (HRper 1-unit increment=0,78 (0,61–1,00), p=0,05). Une interaction significative entre les apports en chaque vitamine B via les compléments alimentaires et l’apport en alcool a été observée, suggérant une association inverse entre ces vitamines et le risque de cancer du sein chez les femmes consommant pas ou peu d’alcool. Conclusion Cette large étude prospective, incluant une évaluation quantitative des apports via les compléments alimentaires, suggère un possible effet protecteur des vitamines B1 et B6 sur le risque de cancer du sein. Elle suggère également une potentielle modulation par la consommation d’alcool des relations entre la prise de compléments alimentaires en vitamine B et le risque de cancer du sein

Analysis method of omics data for metabolic interactions modeling in predictive carcinogenesis

SESSION 1 - EPIDEMIOLOGY - NUTRITIONAL PREVENTION AND CANCER RISKBackground:Currently research focus on the identification of precoce biomarkers is important in the field of Health especially in carcinogenesis. Indeed, specific biomarkers could be crucial to predict the first steps of cancer appearance and to improve cancer prevention and care. In that goal, omic approaches are massively used generating a large amount of data. Our understanding of these data flows become difficult, so it is necessary to develop adaptive tools in order to treat and apprehend them. In many omic studies on cancer-metabolism profiling, discriminant compounds are implicated in energetic pathways such as lipids, glutamin and creatin. For example, lipids are largely used for cancer cell membranes building and undergo a lesser energetic oxidation. Thus, lipids could be used to help for detection of precancer steps.Objective and Methods:This study aims to discern the role of metabolic biomarkers of interest in the first step ofcarcinogenesis. After identification of biomolecules from MS and NMR metabolomic data, we will modelize using softwares allowing dynamic view such as Metaboflux which analyzes flux distribution in metabolic networks, Cytoscape, an open source software, or MetExplore a web server linking metabolomic experiments and genome-scale metabolic networks. We will compare the limits of each software in order to implement the most appropriate to modelize metabolic interactions in predictive carcinogenesis. In this aim, three file formats i.e. Systems Biology Markup Language, JavaScript Object Notation and MAT a format for MATLAB, will be tested.Conclusion:Despite of the existing softwares, most of them do not allow a dynamic visualization of metabolic pathways. That’s why our study plans to implement the most appropriate tool in order to optimize the dynamic modeling of metabolic interaction

Nutrition and cancer in primary prevention: new insights from circadian regulation

International audienceBackground and objectives: Circadian disruption, resulting from shiftwork, has been classified as probably carcinogenic to humans by the International Agency for Research on Cancer. The biological circadian clock is subject to environmental effects, particularly light exposure and rhythmic food intake. However, the association between circadian nutritional behaviors and cancers has never been well explored. We investigated the prospective associations between time of the last eating episode, number of eating episodes, night-time fasting duration and the nutritional quality of the last eating episode, with overall, breast and prostate cancer risks. Methods: This prospective study included 41,389 men and women of the French population-based NutriNet-Santé cohort (2009-2016) who completed at least three 24h-dietary records during the first two years of follow-up. The risk of developing cancer was compared across different groups using multivariable Cox models. Results: 1,732 first primary incident cancer cases were diagnosed during follow-up, among which 428 breast cancers and 179 prostate cancers. Late eaters (last eating episode after 9:30 pm) had an increased risk of breast cancer (HR=1.48 (1.02-2.17), p=0.03) and prostate cancer (HR=2.20 (1.28-3.78), p=0.004); on the other hand, early eaters (last eating episode before 7 pm) had a lower risk of overall cancers (HR=0.78 (0.63-0.96), p=0.02). No association was observed between the number of eating episodes, nighttime fasting duration and the nutritional quality of the last eating episode, with cancer risk. Conclusions: This large cohort study suggests that circadian disruption associated with late time of last food intake may be involved in carcinogenesis at different locations. Beyond nutritional quality of food intake, targeting time of food intake might be interesting in cancer prevention

Sociodemographic and economic factors are associated with weight gain between before and after cancer diagnosis: results from the prospective population-based NutriNet-Santé cohort

Background and objectives: While many cancer patients are affected by weight loss, others tend to gain weight, which may impact prognosis and risk of recurrence and of second cancer. The aim of this prospective study was to investigate weight variation between before and after cancer diagnosis and socio-demographic, economic, lifestyle and clinical factors associated with moderate-to-severe weight gain. Methods: 1051 incident cases of first primary cancer were diagnosed in the NutriNet-Santé cohort between 2009 and 2015. Weight was prospectively collected every 6 months since subjects’ inclusion (i.e. an average of 2y before diagnosis). Mean weights before and after cancer diagnosis were compared with paired Student’s t-test. Factors associated with moderate-to-severe weight gain (≥5% of initial weight) were investigated by age and sex-adjusted logistic regression. Results: Weight loss was observed in men (-3.54±4.39kg in those who lost weight, p=0.0002) and in colorectal cancer patients (-3.94±4.40kg,p=0.001). Weight gain was observed in breast and skin cancers (2.83±3.21kg,p=0.04, and 2.96±2.75kg,p=0.04 respectively). Women (OR=1.75[1.06-2.87],p=0.03), younger patients (2.44[1.51-3.70],p<0.0001), those with lower income (OR=1.30[1.01-1.72],p-trend=0.007), lower education (OR=1.32[1.03-2.70],p-trend=0.03), excess weight before diagnosis (OR=1.64[1.12-2.42],p=0.01), lower physical activity (OR=1.28[1.01-1.64],p=0.04) and those who stopped smoking (OR=4.31[1.99-9.35],p=0.005]) were more likely to gain weight. In breast cancer patients, induced menopause was associated with weight gain (OR=4.12[1.76-9.67]), but no association was detected for tumor characteristics or treatments. Conclusions: This large prospective cohort provided original results on weight variation between before and after cancer diagnosis, highlighting different weight trajectories. Socio-demographic and economic factors appeared to influence the risk of weight gain, illustrating social inequalities in health

Fasting and restrictive diet to lose weight among cancer survivors: profiles, sources of nutritional information, knowledges and opinions: results from the NutriNet-Santé cohort

Background and objectives: Cancer survivors need to get more actively involved in their disease, notably through their nutritional behavior. For instance restrictive diets may be considered, including fasting practice or restrictive diets to lose weight. For the moment, no previous study has investigated theses both types of restrictive diets among cancer survivors. Aims of this study were to describe profiles of patients having practiced fasting or restrictive diet to lose weight after cancer diagnosis and to investigate knowledges/opinions of these patients and their sources of nutritional information, among cancer survivors in a large web based cohort. Methods: In the NutriNet-Santé cohort, 10,309 cancer survivors received the “Sources of information and knowledges/opinions about nutrition” questionnaire in June 2016. Among them 2,942 completed it in October 2016. Associations were explored by multivariate logistic regression adjusted for socio-professional and lifestyle factors. Results: 4.5% of participants had already practiced fasting practices since their diagnosis. They were more likely to be women (p=0.01), youngers (p=0.03), with higher educational level (p=0.003), lower incomes (p=0.004), to use dietary supplements (p=0.03) and practice higher physical activity (p=0.01). 32.2% of patients had practiced restrictive diet to lose weight since diagnosis with higher proportion of women (p<0.0001), professionally active (p<0.05), breast cancer (p=0.0008), overweight (p<0.0001), and of patients using dietary supplements (p=0.0002). Logically, patients reporting believe to the effect of fasting on improved cancer prognosis were more likely to practice fasting (p<0.0001). Contrary, there was no relation between patient’s knowledges of the links between overweight and cancer prognosis and tendency to practice restrictive diet (p=0.4). Patients who practiced fasting after cancer diagnosis were less likely to have receive nutritional information by a healthcare professional (p=0.001) and less likely to be proposed nutritional monitoring (p=0.002). Patients who practiced diet after cancer diagnosis were less likely to have received nutritional information by a healthcare professional (p<0.0001) and less likely to be proposed nutritional monitoring (p=0.0002). Conclusions: These results show that fasting was practiced for its impact on their disease, while diet was not practiced to their cancer. Discussing this matter with a healthcare professional or following a nutritional program would have an impact on practicing a restrictive diet