Ketogenic Diet with Letrozole in Treating Patients with Estrogen Receptor Positive Breast Cancer

Inclusion Criteria

• All participants must be female and at least 18 years of age.
• All participants must provide written informed consent.
• Patients must have histologically confirmed primary invasive mammary carcinoma. * The tumor must be estrogen receptor positive. * The tumor must be HER2 negative (negative immunohistochemistry [IHC] or fluorescence in situ hybridization [FISH]). * The primary tumor size must be at least 2 mm in size.
• Patients must be post-menopausal defined by any of the following: * Subjects at least 55 years of age. * Subjects younger than 55 years of age and amenorrheic for at least 12 months or serum follicle-stimulating hormone (FSH) levels and estradiol levels in the post-menopausal range by local lab criteria * Subjects with history of bilateral oophorectomy or prior radiation castration with amenorrhea for at least 6 months.
• Patients must have clinical stage I, II, or III invasive mammary carcinoma planning to undergo surgical treatment with either segmental resection or total mastectomy.
• Patients must have body mass index (BMI) >= 30.
• A core biopsy from the time of diagnosis must be available.
• Mammogram or ultrasound required prior to screening
• Serum creatinine =< 1.5 x upper limit of normal (ULN). (Measured any time within 120 days prior to study entry)
• Serum glutamic-oxaloacetic transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) =< 4 x ULN (unless known steatohepatitis). (Measured any time within 120 days prior to study entry)
• Serum albumin >= 2.0 g/dL. (Measured any time within 120 days prior to study entry)
• Total serum bilirubin =< 1.5 x ULN (or =< 3 x ULN if known Gilbert’s syndrome). (Measured any time within 120 days prior to study entry).

Exclusion Criteria

• Patients with locally advanced disease who are candidates for other preoperative (chemo)therapy at the time of initial evaluation. This includes patients with inflammatory breast cancer.
• Evidence of distant metastatic disease (stage IV).
• Serious medical illness that in the judgment of the treating physician places the patient at high risk of operative mortality.
• Serious medical illness that in the judgment of the treating physician would preclude the use of a ketogenic diet.
• Severe uncontrolled malabsorption condition or disease (e.g. grade II/III diarrhea, severe malnutrition, short gut syndrome).
• Diabetes mellitus requiring insulin therapy.
• Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent.
• Participation in any other neoadjuvant therapeutic clinical trial.
• Concurrent anti-cancer therapy other than endocrine therapy (e.g. chemotherapy, radiotherapy, immunotherapy, or any other biologic therapy).
• Concurrent treatment with an investigational agent.
• Use of an investigational drug within 30 days or 5 half-lives, whichever is longer, preceding the first day of dietary intervention.