The Role and Challenges of CT Colonography in Colorectal Cancer Screening in Japan

Abstract

Colorectal cancer (CRC) remains a leading cause of cancer mortality in Japan, despite the availability of fecal occult blood testing (FOBT) as a primary screening tool. Follow-up colonoscopy is the standard for FOBT-positive individuals; however, low follow-up rates and the burden on endoscopy resources pose persistent challenges. CT colonography (CTC) is a minimally invasive imaging modality that offers a promising alternative for colorectal cancer screening.

Although CTC has been covered by national health insurance since 2012, its adoption remains limited. Barriers include complex bowel preparation protocols, the need for trained personnel, and limited awareness of recent legislative changes that allow radiological technologists to perform the entire CTC procedure. Recent advances, such as simplified preparation methods, task-shifting to technologists, artificial intelligence (AI)-assisted interpretation, and standardized protocols, are addressing these issues.

CTC provides high sensitivity for detecting polypoid lesions and may improve detection of flat lesions through enhanced imaging techniques and AI. Radiation exposure has been significantly reduced with modern low-dose CT technologies. Furthermore, CTC enables the screening of extracolonic organs, providing added clinical value.

CTC is expected to contribute to a more efficient, patient-friendly, and integrated CRC screening system when combined with FOBT and colonoscopy. Its broader implementation may help reduce CRC mortality by increasing follow-up rates and diagnostic capacity in Japan.