to analyze the feasibility for patients with early luminal breast cancer to be compliant with a diet modification - ketogenic or proteins restricted diet - during 9 +/- 1 days, before breast cancer surgery.

It's a Pilot study, monocentric, randomized

Many patients are modifying their diet after the diagnosis of cancer. There is a supposedly benefit, among the general public, of starving cancer cells with several diet deprivations.

Due to the lack of coherent scientific data, no evidence base recommendations can be made regarding the optimal diet during cancer and its effect on cancer growth.

The objective of this trial is to analyze the feasibility for patients with early luminal breast cancer to be compliant with a diet modification - ketogenic or proteins restricted diet - during 9 +/- 1 days, before breast cancer surgery.

The primary objective of the trial is to evaluate the compliance to the proposed diet.

The study will be conducted in patients with luminal early breast cancer, candidate to primary surgery, in order to study an homogeneous population of patients, with good performance status and without nutritional deprivation.

Metabolic changes on the main metabolic pathways and the potential antitumor effects related to these metabolic changes following the diet will be analyzed as secondary objectives of the study. We hope to find biological hypotheses to further test in a next larger prospective trial.

The impact of the patient's beliefs, anxiety and/or depression on the compliance will be analyzed as well.

Inclusion Criteria:

• Women 18 to 80 years old
• Invasive breast carcinoma, non-metastatic, stage I to III, pathologically proven, ER and/or PR positive, HER2 negative (luminal)
• No treatment yet for the current breast cancer
• Candidate for primary surgery
• Body mass index (BMI) between 18.5 and 30 for women up to 70 years old and between 21 and 30 for women between 70 and 80 years old.
• For patient ≥ 70 years, score of the Oncodage G8 questionnaire > 14 (if score ≤ 14, consultation with an oncogeriatrician required to validate the possibility of following a diet
• No addiction (alcohol, tobacco, drug, electronic cigarette) that modifies the metabolism (alcohol : ≤ 2 glasses/d or ≤10 glasses/week ; tobacco : only occasional or stopped for ≥ 6 months)
• Performance status 0-1
• Fasting blood test :

Blood cell counts : Neutrophils > 1000/µL, Platelets > 100 000/µL, Hb > 11g/dL Hepatic biology: GOT, GPT, GGT, Phosphatases alcalines < 2x normal value Renal function : clearance > 60 mL /min Lipid profile : Total cholesterol < 1.5 x normal value, HDL>0.35g/L, LDL < 2.2 g/L (<5.7 mml/L), Triglycerides < 1.5 x normal value Fasting blood glucose < 1.26 g/l Measurement of electrolytes: Potassium, Sodium, Calcium, Magnesium (according to normal laboratory values)

• ECG with a QTc interval ≤ 450 msec
• Patient able to understand, participate and give a written consent for participation to the study

Exclusion Criteria:

• Metabolic disease or other disease impairing the metabolism analysis
• High level athlete
• Unintentional weight loss ≥ 5% during the last month, or 10% during the last 6 months or compared to usual weight
• Unjustified dietary supplement (not justified by a measured deficiency) during the last month
• Restricted of unbalanced diet (vegan diet, restricted hypocaloric, hyper or hypo protein…) during the last month
• Practice of fasting during the last 3 months
• Corticoids that can't be stopped or not stopped for 2 weeks
• Mellitus diabetes (with or without insulin)
• Hypercholesterolemia requiring a treatment
• Invasive lobular carcinoma
• Pregnant or breast-feeding women
• Participation to another study with an investigational treatment during the last 30 days
• Individuals under the protection of a conservator
• Unaffiliated patient to Social Protection System.

All data will be available after publication of the results in peer-reviewed revues, and in national and international meetings. It includes all disidentified participants' data, the study protocol, the statistical analysis plan, the clinical study report and the analytic code. The corresponding author will provide data and datasets generated and/or analyzed during the study upon reasonable request.

Access to study data upon written detailed request sent to the institute of Montpellier Cancer (ICM), following publication and until 5 years after publication of summary data.

The data shared will be limited to that required for independent mandated verification of the published results, the applicant will need authorization from ICM for personal access, and data will only be transferred after signing of a data access agreement.