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Premalignant diseases of the gastrointestinal tract, such as Barrett's esophagus, long-standing ulcerative colitis, and
adenomatous polyps, have a significantly increased risk for development of adenocarcinoma, most often through an
intermediate stage of dysplasia. Adenocarcinoma of the colon is the second most common cancer in the United States.
Because patients with colorectal cancer often present with advanced disease, the outcomes are associated with
significant morbidity and mortality. Effective methods of early detection are essential. As non-polypoid dysplasia is not
visible using conventional endoscopy, surveillance of patients with Barrett's esophagus and ulcerative colitis is
performed via a system in which multiple random biopsies are obtained at prescribed intervals. Sampling error and
missed diagnoses occur frequently and render current screening methods inadequate. Also, the examination of a tissue
biopsy is time consuming and costly, and significant intra- and inter-observer variation may occur. The newer methods
discussed herein demonstrate the potential to solve these problems by early detection of disease with high sensitivity and
specificity.
Conventional endoscopy is based on the observation of white light reflected off the tissue surface. Subtle changes in
color and shadow reveal structural changes. New developments in optical imaging go beyond white light, exploiting
other properties of light. Several promising methods will be discussed at this meeting and shall be briefly discussed
below. However, few such imaging modalities have arrived at our clinical practice. Some much more practical methods
to improve colorectal cancer screening are currently being evaluated for their clinical impact. These methods seek to
overcome limitations other than those of detecting dysplasia not visible under white light endoscopy. The current
standard practice of colorectal cancer screening utilizes colonoscopy, an uncomfortable, sometimes difficult medical
procedure. Efforts to improve the practice of colonoscopy will be described. Another limitation of the current practice is
the inability to detect polypoid neoplasia that is hidden from view under white light imaging by the natural folds that
occur within the colon. A device to overcome this limitation will also be described. Efforts to improve colorectal cancer
screening (and thereby decrease the death rate of this second leading cause of cancer death in the United States) are
progressing in many arenas. The researcher, basic or clinical, should maintain an up to date overview of the field and
how each new technological advance is likely to have a role in the screening and early detection of colorectal cancer.
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