Cancer in Patients With Familial Adenomatous Polyposis: A Nationwide Danish Cohort Study With Matched Controls

Area of Science:

• Oncology
• Genetics
• Epidemiology

Background:

• Familial adenomatous polyposis (FAP) is an inherited condition increasing colorectal cancer (CRC) risk.
• While prophylactic colectomy reduces CRC, FAP is linked to other cancer risks.
• This study investigates FAP's association with primary and secondary cancer risks.

Purpose of the Study:

• To assess the risk of specific primary and secondary cancers in FAP patients compared to matched controls.
• To quantify the cancer risk associated with FAP, considering various cancer types.

Main Methods:

• Utilized the Danish Polyposis Register to identify FAP patients up to April 2021.
• Matched each FAP patient with four controls based on birth year, sex, and postal code.
• Analyzed overall cancer risk, specific cancer types, and second primary cancer risk.

Main Results:

• Included 565 FAP patients and 1890 controls.
• FAP patients had a 4.12-fold higher overall cancer risk (P < .001).
• Significantly increased risks observed for colorectal (HR 4.61), pancreatic (HR 6.45), and duodenal/small-bowel cancers (HR 14.49).
• FAP patients had a 1.89-fold higher risk of a second primary cancer (P = .042).
• Cancer risk in FAP patients decreased by approximately 50% between 1980 and 2020.

Conclusions:

• FAP patients face a persistently higher cancer risk, particularly for colorectal, pancreatic, and duodenal/small-bowel cancers.
• Despite risk reductions, vigilance for these cancers in FAP patients remains crucial.
• The study highlights the importance of ongoing monitoring and management for FAP-associated cancers.