Preinvasive lesions of the bronchus.

It has been proposed that invasive carcinoma of the bronchus develops through a transition from preinvasive lesions to overt malignancy. Newer diagnostic technologies have provided a more sensitive way to diagnose preinvasive lesions and a better understanding of the prevalence of such lesions. The natural history of preinvasive lesions has not been well defined; however, there is evidence that high-grade lesions are at a higher risk of progression to carcinoma. Molecular alterations have been described in preinvasive lesions and may help better predict which lesions will progress. Several noninvasive techniques are available for the treatment of high-grade lesions.