Endoscopy and Early Neoplasia: Better but not the Best

Forecast: Turbulence in the Air

The secondary prevention of cancer of the digestive system relies on the logical assumption that early detection benefits the patient. Endoscopy is the gold standard procedure in early detection of neoplasia (either confirmed cancer or high-grade and low-grade dysplasia), particularly when the morphology is not polypoid. Furthermore, diagnosis is often accompanied by treatment in the same endoscopy session.

The endoscopic standard has been supported, since the 1970s, by continuous technological progress, under Japanese leadership. The mechanical characteristics of the fiberscope have improved, as has the image obtained. A major step has been the shift from the fiber bundle to the charge-coupled device (CCD). High-resolution fiberscopes, now routinely available, detect mucosal areas to be explored by chromoscopy through minimal changes in colour and relief. The quality of the digital image depends on the multistep processing of the data collected by a CCD with a large number of pixels, and an improved optical construction (larger endoscopic field of view, wider angle of view), as far as the analogue display on the monitor. Recently structure enhancement processing has improved the contrast of flat mucosal defects, facilitating the detection of depressed lesions.

Endoscopists have willingly followed this smooth progress, and one may speculate that an experienced operator using an instrument in the early 1980s would not miss many details when compared with the operator in the year 2000. Indeed the features of flat neoplastic lesions have been described extensively over more than 20 years in Japan. However we are now entering a turbulent period, as a consequence of the raising of endoscopic standards. The potential excess in the number of detected lesions raises the first question: are we able to predict, without the aid of histology, which lesions should be treated and which should be neglected? Are we confident with a negative endoscopic exploration when screening asymptomatic persons, either as individuals or as part of a mass program? What level of reassurance can we communicate to the patient?

In this issue of Endoscopy, three separate papers from Japan [1] [2] [3] focus on the endoscopic detection of early cancer in the digestive tract. These papers indicate limiting factors in spite of the new technology, and show that although the potential for diagnosis is high, it is still not at its maximum. The Japanese school of digestive endoscopy leads the field in the description of the early stages of neoplastic lesions in the esophagus, stomach, and intestine. Japan is also a leader in national screening programs for stomach cancer, and more recently for colorectal cancer. In Japan, 7 million people are screened annually for stomach cancer [4].

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