Investigation of β-hydroxybutyrate Supplementation as Chemoprevention in Familial Adenomatous Polyposis

Inclusion criteria

• Have a diagnosis of FAP with genetic testing demonstrating a pathogenic or likely pathogenic germline variant in APC, must have a clinical FAP phenotype with at least one member of the family who has a pathogenic or likely pathogenic germline variant in APC, or must have a clinical diagnosis of FAP as agreed by two gastrointestinal cancer genetics experts
• Must have an extensive colonic resection with either a subtotal colectomy with ileorectal anastomosis (STC-IRA) or total proctocolectomy with ileal pouch anal anastomosis (TPC-IPAA)
• Can provide informed consent

Exclusion criteria

• Subject is pregnant, a prisoner, or is under 18 years of age
• Prior total proctocolectomy with end ileostomy
• History of inflammatory bowel disease
• History of diabetes mellitus and are currently on medical diabetes therapy
• History of chronic kidney disease with an eGFR \< 60 mL/min/1.73m2
• Cancer diagnosis where the subject is receiving active therapy
• Use of either a ketogenic diet or intermittent fasting (defined as a fasting period of 16 hours or more per day that is not associated with a medical procedure) during the 4 weeks prior to enrollment
• Part B
• Inclusion Criteria:
• Have a diagnosis of FAP with genetic testing demonstrating a pathogenic or likely pathogenic germline variant in APC, must have a clinical FAP phenotype with at least one member of the family who has a pathogenic or likely pathogenic germline variant in APC, or must have a clinical diagnosis of FAP as agreed by two gastrointestinal cancer genetics experts.
• Willing to undergo a colonoscopy or sigmoidoscopy, which may be part of the patient's routine standard care.
• Able to have a concurrent upper endoscopy performed with the colonoscopy/sigmoidoscopy. This upper endoscopy may be part of the patient's routine standard care.
• Have at least two colorectal polyps at enrollment (which can be present anywhere in the colon including the rectal cuff, or in the J-pouch \[if applicable\]).
• Can provide informed consent.
• Exclusion Criteria:
• Subject is pregnant, a prisoner, or is under 18 years of age
• Patient is not able to undergo colonoscopy/sigmoidoscopy or upper endoscopy
• Prior total proctocolectomy with end ileostomy
• History of inflammatory bowel disease
• History of diabetes mellitus and are currently on medical diabetes therapy
• History of chronic kidney disease with an eGFR \< 60 mL/min/1.73m2
• Cancer diagnosis where the subject is receiving active therapy
• Use of either a ketogenic diet or intermittent fasting (defined as a fasting period of 16 hours or more per day that is not associated with a medical procedure) during the 4 weeks prior to enrollment
• Regular use of any FAP-related chemopreventive agent in the 6 weeks prior to enrollment including aspirin (\> 81mg daily), NSAIDs, BHB supplementation, or any other medication deemed a chemopreventive agent by the study investigators
• Any colonic or small intestinal polyp observed endoscopically that is \> 1 cm in size and is not removed (excluding ampullary adenomas)