Ketogenic diet before surgery for early-stage breast cancer

Impact of Ketogenic Diet on Tumor Microenvironment in Patients With Breast Cancer

Not applicable Interventional The University of Texas Health Science Center at San Antonio · NCT07574671

This will test whether following a ketogenic diet for three weeks before surgery changes the tumor environment in people with early-stage, postmenopausal breast cancer.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment12 (estimated)
Ages18 Years and up
SexAll
SponsorThe University of Texas Health Science Center at San Antonio Academic / other
Locations1 site (San Antonio, Texas)
Trial IDNCT07574671 on ClinicalTrials.gov

What this trial studies

Eligible participants will meet with a dietitian and receive education and materials to follow a ketogenic diet for three weeks before their planned breast surgery. Participants will measure blood glucose and ketones daily at home and keep a food and activity diary to document adherence. Surgical tissue from the planned upfront operation will be used to examine changes in the tumor microenvironment. The study enrolls adults with stage I–II disease who do not require preoperative systemic therapy and are able to follow the diet and remote monitoring procedures.

Who should consider this trial

Good fit: Ideal candidates are adults (≥18) who are postmenopausal with stage I–II breast cancer, plan for upfront surgery (no neoadjuvant therapy), have ECOG ≤2, and are willing and able to follow a ketogenic diet and daily home monitoring.

Not a fit: Patients who need neoadjuvant therapy, have more advanced or metastatic disease, are premenopausal, or cannot adhere to the diet or home monitoring are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, this could identify a low-cost dietary approach to alter tumor biology before surgery and guide future treatment strategies.

How similar studies have performed: Small pilot studies of ketogenic diets in cancer have shown mixed and limited results, so this approach remains experimental in breast cancer.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Be willing and able to provide consent for the study
* Age ≥ 18 on the day consent is obtained
* Eastern Cooperative Oncology Group (ECOG) score ≤ 2
* Patients must be postmenopausal the time of study entry
* Stage I or II breast cancer using Tumor, Nodes and Metastasis (TNM) stage groups per American Joint Committee on Cancer (AJCC) 8th edition
* Plan for upfront breast surgery with mastectomy or partial mastectomy and does not require pre-operative systemic therapy per standard of care
* Must have tissue available from initial breast biopsy performed per standard of care
* have the ability in the opinion of the investigator to adhere to a ketogenic diet and comply with study requirements such as ability to participate in telemedicine, utilize apps on a smart device, measure glucose/ketones at home, accurately log food intake and exercise, prepare food that is in line with ketogenic diet

Exclusion Criteria:

* Clinical indication for neoadjuvant therapy
* Partial mastectomy or mastectomy planned for less than 3 weeks from study entry
* Inability to comply with ketogenic diet
* Consistent use of ketogenic diet within past 3 months
* Participation in another diet program during study period
* Nonepithelial breast malignancy such as sarcoma or lymphoma
* Body Mass Index \< 18.5
* Comorbidities and/or active or ongoing illness that in the opinion of the investigator will limit patient's ability to safely participate in study
* Type I diabetes
* Use of insulin or other oral hypoglycemic drugs for diabetes
* Has had any of the following within the past 6 months

  * Myocardial infarction or unstable angina
  * Ventricular arrythmia
  * Acute decompensated heart failure
  * Cerebrovascular accident
  * Hypertensive emergency
* Uncontrolled hypertension despite antihypertensive use
* End-stage renal, liver, or cardiac disease
* genetic disorders that affect lipid metabolism (example: pyruvate carboxylase deficiency, porphyria, primary carnitine deficiency, carnitine palmitoyltransferase I or II deficiency, carnitine translocase deficiency, beta-oxidation defects, among others)
* G6PD (glucose-6-phosphate dehydrogenase) deficiency
* Malabsorption syndromes (such as but not limited to inflammatory bowel disease, history of gastric sleeve, prior bowel resection)
* History of recurrent kidney stones or predisposition to kidney stones
* Triglycerides ≥ 500
* Has known psychiatric or substance use disorders that would interfere with participation in the study

Where this trial is running

San Antonio, Texas

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Breast CancerKetogenic dietdietnutrition
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.