PRECANCEROUS STATES OF THE ESOPHAGUS

In the upper aerodigestive tract, carcinogenesis in squamous cell muco sa is characterized by a tendency to field cancerization leading to mu lticentricity of lesions and synchronous or metachronous multiple tumo ral lesions, namely multifocality. During pretherapy bronchoesophagosc opy carried out on ENT-cancer patients, the rate of synchronous second primary cancer is 24%. In 85% of the cases, these second primaries ar e detected at an early stage (in situ, microinvasive or submucosal car cinoma) and do not give rise to symptoms. Early diagnosis of cancer of the upper aerodigestive tract is possible provided that high risk pat ients are recognized and screening endoscopy of the whole mucosa is pe rformed in every high risk patient. On the other hand, squamous cell c arcinoma and adenocarcinoma may occur with increased frequency in pati ents with esophageal lesions such as achalasia, caustic stenosis and B arrett's esophagus. The premalignant potential of these three entities is discussed.