An interventional study of Dietary Protein Intervention in Breast Cancer and Hormone Receptor Positive / HER2-negative Breast Cancer, sponsored by Josephine Connolly-Schoonen. Recruiting at 1 site in United States. Open to female participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-11-06.
Sponsored by Josephine Connolly-Schoonen · Not applicable, Interventional, and Treatment
This study will examine if a short-term, reduced protein diet for the 3-day period prior to and on the day of each of the first 4 chemotherapy cycles and 4 days prior to primary breast surgery is well tolerated and adhered to by patients with stage II or III estrogen receptor positive (ER+) human epidermal growth factor receptor negative (HER2-) breast cancer (BC) receiving neoadjuvant chemotherapy (NAC).
There has been recent interest in the potential anti-cancer effects of nutrition interventions, although little is known about how individual patients' diets can impact the tumor microenvironment, and potentially patient outcomes. This is despite long-standing patient and healthcare provider interest in this type of adjunctive therapy. Therein lies a significant opportunity to develop nutritional recommendations that could exert antitumor effects with minimal, if any, side effects. To meet this opportunity, dietary alterations in cancer patients have been implemented in a surprisingly small number of studies, including the use of ketogenic and fasting-mimicking diets. Although findings from these trials suggest some modest benefit, such extreme alterations proved difficult for patients to adhere to, thus making them impractical for wide-spread use. Studies in humans show that high protein intake significantly increases the likelihood of dying from cancer, and work in rodents shows that feeding a high protein diet enhances carcinogenesis, suggesting that limiting protein intake may have anticancer benefits. Accordingly, investigators at Stony Brook University and others have shown that reducing protein consumption slows tumor growth, enhances anti-tumor immunity and improves the efficacy of anticancer therapy in murine models. These effects likely result from restricting the availability of tumor growth promoting amino acids. However, the impact of lowering protein intake on the biology of patients' tumors is unknown.
Investigators at Stony Brook University have already established a method to reduce protein intake in healthy humans demonstrating strong adherence and correlated biological changes. Positive findings from this trial would justify larger scale randomized controlled feeding trials to evaluate clinical outcomes including pathologic response, treatment tolerance, immune cell infiltration, and overall survival with this intervention. This line of investigation has the potential to provide the first evidence that intermittent dietary protein reduction is a safe, low-cost method to impede tumor growth, optimize response to anti-tumor therapies and improve patient outcomes.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
This study's planned enrollment of 15 is below the median of 72 across 10,896 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →This is the only study on the registry with Josephine Connolly-Schoonen as lead sponsor.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients will receive an intermittent, reduced protein diet for the 3-day period prior to and on the day of each of the first 4 chemotherapy cycles and 4 days prior to primary breast surgery.
Other: Dietary Protein Intervention
Consume an intermittent, reduced protein diet for a total of 20 feeding days over the course of neoadjuvant treatment (at the time of the first four chemotherapy cycles and prior to surgery)
Also known as: Dietary modification, Nutrition intervention, Intervention, dietary, Nutritional intervention
Feasibility of completing the intermittent, reduced protein diet intervention
Percent of enrolled patients that complete the intervention (accept the interventional diet for 3 days before and day of chemotherapy and complete the diet intake surveys for at least 4 of the 5 diet periods) - Measured by uploaded/self-reported meal consumption pictures.
Time frame: Immediately after the intervention/pre-surgery
Recruitment of patients receiving neoadjuvant chemotherapy for breast cancer into an intermittent, reduced protein diet intervention
Enrollment rate, defined as the percentage of patients offered participation who enroll in the study
Time frame: 18 months
Adherence to the intermittent, reduced protein diet among patients receiving neoadjuvant chemotherapy for breast cancer
Percent of patients who consume less or equal to 0.9 g of protein per kilogram of body weight over the intervention period - measured by uploaded/self-reported meal consumption pictures.
Time frame: Up to 20 intervention days
Safety of an intermittent, reduced protein diet - weight change
Longitudinal weight change, measured by the InBody 380 device, in patients receiving neoadjuvant chemotherapy for breast cancer
Time frame: Day of surgery/before surgery
Safety of an intermittent, reduced protein diet - muscle mass change
Longitudinal muscle mass change, measured by the InBody 380 device, in patients receiving neoadjuvant chemotherapy for breast cancer
Time frame: Post-cycle 4 chemotherapy medical oncology visit (each cycle is 21 days)
Safety of an intermittent, reduced protein diet - fat mass change
Longitudinal fat mass change, measured by the InBody 380 device, in patients receiving neoadjuvant chemotherapy for breast cancer
Time frame: Baseline, Cycle 4 Day 1 (each cycle is 21 days) and Preoperative evaluation (average of 6 months)
Safety of an intermittent, reduced protein diet - handgrip strength change
Longitudinal handgrip strength change, measured by the Jamar dynamometer, in patients receiving neoadjuvant chemotherapy for breast cancer
Time frame: Baseline, Cycle 4 Day 1 (each cycle is 21 days) and Preoperative evaluation (average of 6 months)
Safety of an intermittent, reduced protein diet - frequency of post-operative complications
Number of post-operative complications in breast cancer patients receiving neoadjuvant chemotherapy, assessed by chart review
Time frame: One month after primary breast surgery
Safety of an intermittent, reduced protein diet - frequency of episodes of CTCAE greater than or equal to 3 non-hematologic toxicities
Number of episodes of CTCAE greater than or equal to 3 non-hematologic toxicity in patients receiving neoadjuvant chemotherapy for breast cancer, assessed by chart review
Time frame: Chemotherapy Cycle 1 Day 1 to one day before surgery (each cycle is 21 days)
Safety of an intermittent, reduced protein diet - frequency of patients who experience at least one CTCAE greater than or equal to 3 non-hematologic toxicities
Percent of patients who experience at least one CTCAE greater than or equal to 3 non-hematologic toxicity, assessed by chart review
Time frame: Chemotherapy Cycle 1 Day 1 through chemotherapy Cycle 4 Day 0 (each cycle is 21 days)
Safety of an intermittent, reduced protein diet - frequency of dose reduction or delay in chemotherapy
Number of episodes of dose reductions or delays in chemotherapy in patients receiving neoadjuvant treatment for breast cancer, assessed by chart review
Time frame: Chemotherapy Cycle 1 Day 1 through chemotherapy Cycle 4 Day 0 (each cycle is 21 days)
Tolerability of an intermittent, reduced protein diet - change in domain-specific self-reported gastrointestinal symptoms
Change in self-reported Gastrointestinal symptoms measured by survey tool - (Patient-Reported Outcomes Measurement Information System Gastrointestinal (PROMIS-GI)). The PROMIS-GI is a standardized set of symptom scales. It evaluates 61 specific items across 8 domains: belly pain, bowel incontinence, constipation, diarrhea, disrupted swallowing, gas/bloating, gastroesophageal reflux, and nausea/vomiting. Scores are calibrated using standardized T-scores with a mean of 50 and a standard deviation of 10 in the U.S. general population. A higher score denotes more severe or frequent GI symptoms.
Time frame: Baseline, Cycle 1 Day 1 (each cycle is 21 days), Cycle 4 Day 1, and Preoperative evaluation (average of 6 months)
Tolerability of an intermittent, reduced protein diet - change in self-reported total gastrointestinal symptoms
Change in self-reported gastrointestinal symptom scores measured by survey tool - (Patient-Reported Outcomes Measurement Information System Gastrointestinal (PROMIS-GI)). The PROMIS-GI is a standardized set of symptom scales. It evaluates 61 specific items across 8 domains: belly pain, bowel incontinence, constipation, diarrhea, disrupted swallowing, gas/bloating, gastroesophageal reflux, and nausea/vomiting. Scores are calibrated using standardized T-scores with a mean of 50 and a standard deviation of 10 in the U.S. general population. A higher score denotes more severe or frequent GI symptoms.
Time frame: Baseline, Cycle 1 Day 1 (each cycle is 21 days), Cycle 4 Day 1, and Preoperative evaluation (average of 6 months)
Tolerability of an intermittent, reduced protein diet - change in subjective global assessment score
Change in subjective global assessment score measured by survey tool (Patient Generated Subjective Global Assessment (PG-SGA)). The PG-SGA is a 9-questions survey used to screen for malnutrition. It is a validated instrument that evaluates weight history, food intake, nutrition-related symptoms, functional status, disease-related metabolic stress, and physical findings to determine malnutrition risk and nutritional status. The PG-SGA total score ranges from 0 upward, with higher scores indicating greater nutritional risk and increased need for nutrition-related intervention.
Time frame: Baseline, Cycle 1 Day 1 (each cycle is 21 days), Cycle 4 Day 1, and Preoperative evaluation (average of 6 months)
Plan to share: No
No publications or documents are linked to this record.
Started Nov 2026 (actual). Primary completion is estimated for Oct 2028, 23 months after the start.
Of 2,661 non-industry interventional studies with no phase under Breast Neoplasms, half reached primary completion within 33 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 66. This study's planned 23 months is below that.
Counting every sponsor, half of 2,771 studies reached it within 33 months; a quarter within 15 and three quarters within 66.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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