Gastrointestinal cancer is one of the most common malignancies worldwide. In particular, colorectal cancer is the second most common cancer in developed countries, where 390,000 new cases are found every year. In Japan, colorectal cancer is the 1st and 3rd leading causes of cancer deaths among women and men, respectively, where more than 42,000 people die of colorectal cancer every year. However, colorectal cancer can be completely preventable if precursor colorectal lesions are detected and removed early. Thus, screening is vitally important for reducing deaths from colorectal cancer. Current screening techniques available include fecal occult blood test, barium enema, and colonoscopy. However, none of these examinations is optimal in terms of capacity, safety, patient acceptance, and diagnostic performance.
Virtual colonoscopy (VC), also known as computed tomographic (CT) colonography, provides a minimally invasive screening method for early detection of colorectal lesions and has the potential to solve the problems of capacity and safety with conventional colorectal screening methods. Rapid advancement in CT imaging technology and computer-aided diagnosis techniques have made VC an effective examination for early detection of colorectal cancer, and several large-scale multicenter clinical trials in the United States, Europe, and Japan demonstrated that the VC has high premise to a forefront technique for mass screening of colorectal cancer.
In this talk, a brief overview will be provided regarding the history and current status of the VC-based colon cancer screening. Then, recent developments in making the VC examination be “patient friendly” will be described, including laxative-free bowel preparation and virtual bowel cleansing. Also, recent advances in computerized detection of subtle colorectal lesions such as small polyps and flat lesions will be presented, followed by the up-coming next generation VC examination based on dual energy CT imaging. The talk will then describe the prospect of the could-supercomputing service of VC-based screening for effective mass screening in the near future.