Early diagnosis of lung cancer

Abstract

A large randomized controlled trial, The National Lung Screening Study (NLST), has demonstrated that screening with low-dose spiral computed tomography saved lives from lung cancer when compared with screening with chest radiographs. This is the first test showing efficacy in screening for lung cancer as previous trials of chest radiographs and sputum cytology failed to result in fewer deaths with screening. This review will examine the problem of lung cancer, the issues presented by screening, and the results of computed tomography (CT) studies for lung cancer screening. Now that CT screening has been shown to be effective, implementation of screening becomes the next step.

Figure 1.. Early stage detection

A 62 year old woman, former smoker with a 40-pack year history had a low dose screening CT showing a 3 mm nodule (A) in the left lung (lingula). At one-year follow-up, the nodule had grown (B) and at surgical resection was a 6 mm adenocarcinoma. She remains without evidence of disease seven years after removal.

Figure 2.. Probable overdiagnosis

An 80 year old woman, former smoker, with a history of a left upper lobectomy for a stage I adenocarcinoma, has an 11 mm (arrow) ground glass opacity in the right upper lobe. The nodule has not changed in over 3-years and is currently being followed with annual CT. If this is a cancer it is likely to be an adenocarcinoma in situ and may represent and overdiagnosis cancer.