Fasting for Breast Cancer

(GAMMER Trial)

Recruiting at 1 trial location

Overseen By Jennifer Sheng, MD

Age: 18+

Sex: Female

Trial Phase: Academic

Sponsor: Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins

Must not be taking: Food-required medications

Disqualifiers: Diabetes, Eating disorder, Uncontrolled conditions, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 7

30 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether fasting for 24-48 hours with only water can enhance chemotherapy's effectiveness for breast cancer patients. It focuses on patients receiving therapy either before or after surgery to determine if fasting improves chemotherapy outcomes. Participants will fast before their chemotherapy sessions to test this hypothesis. This trial suits those diagnosed with stage I-III breast cancer, planning specific chemotherapy treatments, and willing to make dietary changes. As an unphased trial, it offers a unique opportunity for patients to contribute to innovative research that could improve future cancer treatments.

Will I have to stop taking my current medications?

If you are taking medications that must be taken with food, such as aspirin, lithium, or prednisone, you may need to stop them to participate in this trial. The protocol does not specify other medication restrictions.

What prior data suggests that fasting is safe for breast cancer patients undergoing chemotherapy?

Research suggests that fasting might be safe for people with cancer. Early studies show that fasting for extended periods can be safe and may help lessen chemotherapy side effects. For instance, one study found that fasting was safe and beneficial for individuals with long-term illnesses like rheumatic diseases.

Notably, fasting has been linked to a lower risk of breast cancer recurrence. Those who fasted for 13 hours or more had a 36% lower chance of the cancer returning compared to those who fasted for shorter periods. While more research is needed, current studies indicate that fasting could be a safe option during cancer treatment. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about fasting as a treatment for breast cancer because it offers a completely different approach compared to traditional therapies like chemotherapy and targeted drugs. Fasting prior to chemotherapy might enhance the treatment's effectiveness by putting stress on cancer cells while protecting normal cells, potentially leading to fewer side effects. This technique is simple and doesn't involve new drugs or complex procedures, allowing it to be easily integrated with existing cancer treatments. Plus, if proven effective, fasting could provide a cost-effective and accessible way to improve cancer care outcomes.

What evidence suggests that fasting might be an effective treatment for breast cancer?

This trial will evaluate the effects of fasting before chemotherapy for breast cancer patients. Studies have shown that fasting might reduce chemotherapy side effects in some cancer patients. Research suggests that fasting could protect healthy cells and make cancer cells more sensitive to treatment. Early findings indicate that fasting might be safe and could lower the risk of breast cancer recurrence. While more research is needed, fasting appears promising for enhancing chemotherapy's effectiveness in breast cancer patients. ^{1 2 3 4 5}

Who Is on the Research Team?

Jennifer Sheng, MD

Principal Investigator

Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins

Are You a Good Fit for This Trial?

This trial is for individuals undergoing chemotherapy for breast cancer, either before or after surgery. Participants will try water-only fasting for 24-48 hours to see if it helps with the treatment.

Inclusion Criteria

Provider physical exam within 4 weeks of consent

BMI ≥ 19.5 kg/m2 (as per most recent visit documented in medical record)

Willingness to change diet, and provide fecal sample 3 times during study

Exclusion Criteria

I have diabetes.

BMI <19.5 kg/m2

Pregnant or nursing

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Dose Finding

Participants undergo a dose finding for fasting, requiring at least one successful 24-hour fast with a maximum of three trials allowed.

1-3 weeks

Up to 3 visits (in-person)

Chemotherapy with Fasting

Participants receive chemotherapy with a fasting regimen, consisting of 4 cycles of chemotherapy with fasting interventions.

8-12 weeks

4 visits (in-person) for chemotherapy cycles

Follow-up

Participants are monitored for safety and effectiveness after treatment, including assessments of cytokines, metabolites, and gut microbiome.

6-8 months

What Are the Treatments Tested in This Trial?

Interventions

• Fasting

Trial Overview The study is testing whether short-term fasting can make chemotherapy more effective in treating breast cancer. Patients will fast for one to two days during their chemo cycles.

How Is the Trial Designed?

Group I: Fasting prior to chemotherapy Experimental Treatment 1 Intervention

Prior to chemotherapy administration, a trial of a 24-hour water-only fast will be conducted; at least 1 successful 24-hour fast is required to proceed with the fasting intervention during chemotherapy. A total of 3 trials is allowed (for a maximum of 48 hours fasting).

Who Is Running the Clinical Trial?

Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins

Lead Sponsor

Trials

578

Recruited

33,600+

The Commonwealth Fund

Collaborator

Trials

13

Recruited

228,000+

Maryland Cigarette Restitution Fund

Collaborator

Trials

10

Recruited

900+

Published Research Related to This Trial

Habitual continuous energy restriction (CER) has been shown to effectively prevent breast tumor formation in both animal studies and observational studies in women, while intermittent energy restriction (IER) and intermittent fasting (IF) may offer easier and potentially more effective alternatives for weight control and cancer prevention.

Animal studies suggest that IER and IF can reduce mammary tumor formation and may have different mechanisms of action compared to CER, including greater reductions in fat stores and improved insulin sensitivity, but more research is needed to directly compare these methods in humans.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Energy restriction and the prevention of breast cancer. Harvie, M., Howell, A.[2013]

Intermittent fasting (IF) during chemotherapy for breast cancer patients significantly reduced gastrointestinal toxicity compared to a non-fasting group, suggesting a protective effect of fasting against chemotherapy side effects.

The study, involving 48 HER2-negative breast cancer patients, also indicated that IF improved metabolic profiles, as evidenced by lower insulin levels in the IF group, which may enhance the overall efficacy of chemotherapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent fasting during adjuvant chemotherapy may promote differential stress resistance in breast cancer patients. Omar, EM., Omran, GA., Mustafa, MF., et al.[2022]

Preliminary findings indicate that combining intermittent fasting or a fasting-mimicking diet with endocrine therapy may enhance the effectiveness of treatment for hormone receptor-positive breast cancer.

This combination approach could also help in reducing side effects associated with the endocrine therapy, suggesting a potential strategy for improving patient outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fasting May Complement Endocrine Therapy. [2021]

Intermittent energy restriction (IER) led to a significant weight loss of 4.8% and reduced insulin resistance by nearly 30% during restricted days in 23 overweight premenopausal women at high risk for breast cancer, suggesting potential metabolic benefits.

The study found variable transcriptional responses in breast tissue to IER, with some women showing beneficial gene expression changes related to breast epithelial cell differentiation, while others did not exhibit any significant changes, indicating that individual responses to IER may differ and warrant further investigation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent energy restriction induces changes in breast gene expression and systemic metabolism. Harvie, MN., Sims, AH., Pegington, M., et al.[2022]

Intermittent fasting (IF) during chemotherapy for breast cancer patients was found to be feasible and safe, potentially alleviating chemotherapy-induced adverse effects like fatigue and nausea, although the quality of the data was low.

While IF showed some promise in reducing chemotherapy-induced DNA damage and improving glycemic regulation, the review did not find significant benefits on quality of life or tumor recurrence, indicating that more rigorous studies are needed to confirm these effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent Fasting in Breast Cancer: A Systematic Review and Critical Update of Available Studies. Anemoulis, M., Vlastos, A., Kachtsidis, V., et al.[2023]

Periodic fasting enhances the effectiveness of endocrine treatments for hormone receptor-positive breast cancer by increasing their anti-cancer activity.

Fasting may help delay the development of resistance to these treatments by lowering levels of blood leptin, insulin, and insulin-like growth factor 1 (IGF1), suggesting a potential new strategy for improving breast cancer therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Enhancing endocrine therapy activity via fasting cycles: biological rationale and clinical feasibility. Caffa, I., Nencioni, A.[2021]

Intermittent energy restriction (IER) has been shown in animal studies to be more effective than continuous energy restriction (CER) in reducing tumor rates, suggesting potential anticancer benefits.

Limited human studies indicate that IER may improve insulin sensitivity more than CER in overweight and obese individuals, but more long-term research is needed to confirm these findings and assess safety and efficacy in both overweight and normal-weight populations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Could Intermittent Energy Restriction and Intermittent Fasting Reduce Rates of Cancer in Obese, Overweight, and Normal-Weight Subjects? A Summary of Evidence. Harvie, MN., Howell, T.[2023]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9920353/

Intermittent Fasting in Breast Cancer: Review & Update Fasting for less than 13 h per night is connected with a 36% greater risk of the recurrence of breast cancer when compared to individuals fasting for ≥13 h per ...

2. nature.com nature.com/articles/s41416-025-03129-8

Randomised phase-2 screening trial of intermittent energy ... Weight control and energy restriction could improve survival in patients with advanced breast cancer (ABC) but randomised data are lacking.

3. sciencedirect.com sciencedirect.com/science/article/pii/S2161831322007542

Intermittent Energy Restriction & Fasting for Cancer Reduction? Observational evidence indicates that weight reduction with energy restriction (ER)3 reduces the risk of breast cancer (3, 4), whereas weight reduction with ...

4. acsjournals.onlinelibrary.wiley.com acsjournals.onlinelibrary.wiley.com/doi/full/10.3322/caac.21694

Intermittent fasting in the prevention and treatment of cancer Preliminary studies suggest that prolonged fasting in some patients who have cancer is safe and potentially capable of decreasing chemotherapy-related toxicity ...

5. osher.ucsf.edu osher.ucsf.edu/patient-care/integrative-medicine-resources/cancer-and-nutrition/faq/cancer-and-fasting-calorie-restriction

Cancer and Fasting / Calorie Restriction Comparing the research between CR and fasting, fasting seems to provide more dramatic results and protection of healthy cells, without the risk of weight loss ...