ABSTRACT

The tracheobronchial tree is a complex branching system with a surface area that is equivalent to the size of a tennis court. Squamous cell carcinoma and small cell carcinoma are more commonly found in the central airways while adenocarcinomas are usually found in the peripheral airways or lung parenchyma beyond the range of a standard, adult-size flexible bronchoscope. Thoracic CT scan is a sensitive tool in the detection of early peripheral lung cancers especially adenocarcinomas,1-10 but is suboptimal for the detection of early central squamous cell carcinoma.10 Squamous cell carcinoma in-situ or micro-invasive cancers have high 5-year survival rates of >90% and are therefore clinically important lesions to detect and treat with the intention of cure.11,12 Despite the rising incidence of adenocarcinoma worldwide, squamous cell carcinoma still accounts for a significant proportion of lung cancer cases, ranging from 37% and 20% in men and women respectively in the United States and Canada, to 47% and 27% in men and women respectively in Europe.13 In one recent report that assessed the combined role of CT scan and autofluorescence bronchoscopy in a screening program, approximately 25% of lung cancers detected were CT occult squamous carcinoma in-situ or microinvasive cancer diagnosed by autofluorescence bronchoscopy alone.10 Bronchoscopy complements thoracic CT in the diagnosis of early lung cancer with the added advantage that a cytological or tissue sample can be obtained in the same procedure for definitive diagnosis.