Fast-Her: Fasting Effects on Breast Cancer Treatment

Fast-Her: Fasting Effects on Breast Cancer Treatment

We hypothesize that promoting a fasting state will strengthen the anti-cancer effects of PI3K inhibitors in metastatic breast cancer (MBC) treatment. The primary objective of this study is to assess acceptability of prolonged fasting in this population.

Inclusion Criteria:

• Age ≥18 years
• Histologically confirmed metastatic breast cancer
• Menopausal or medically ovarian suppressed
• Currently receiving capivasertib therapy (2 tablets twice daily, 4 days per week)
• Stable on current capivasertib regimen for at least 2 weeks
• an ECOG performance status of 0-1
• BMI ≥25kg/m2
• Able to provide informed consent
• Willing to comply with study procedures including CGM wear, food tracking by mCC app and dietary modifications
• Access to smartphone or tablet for mobile application use

Exclusion Criteria:

• Type 1 diabetes mellitus
• Uncontrolled type 2 diabetes (HbA1c >9.0%)
• History of severe hypoglycemia
• Eating disorders or contraindications to fasting
• Pregnancy or breastfeeding
• Significant gastrointestinal disorders affecting food absorption
• Unable to fast for medical reasons
• Concurrent participation in other dietary intervention studies
• A history of significantly abnormal lab results within 4 weeks of consent date, such as hematologic (Hgb < 10.0, platelets < 100), hepatic (LFTs > 2X nl), renal (Cr > 1.5)