Non-small Cell Lung Cancer
Diagnosis
In around 5% of cases, usually of early-stage disease, initial presentation is a chance finding during routine examination for other conditions and no symptoms are evident. The clinical features of advanced lung cancer may include persistent cough, expectoration of sputum, haemoptysis, wheeze or stridor, dyspnoea, chest discomfort or pain and lack of energy or loss of interest in normal pursuits.
Radiological assessment of the chest is the simplest and most convenient method for the diagnosis of lung cancer and provides early information on the location, size and spread of the tumour as well as the involvement of surrounding tissues. Lung function testing is considered essential for diagnosis, especially where surgery is being considered. Cytological examination is required for a complete diagnosis and accurate staging and can be obtained by various methods including bronchial biopsy, percutaneous biopsy or sputum cytology. Computerised tomography (CT) scanning is being used increasingly for staging as it gives improved assessments of the site, size and extension of the tumour, and lymph node involvement, compared with conventional radiography. Total body F18-2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) has been reported to improve diagnostic accuracy in the staging of NSCLC.
The possibility of metastatic spread must be investigated to complete the diagnosis and staging process and to determine an appropriate treatment strategy. As with other solid tumours the available techniques are relatively crude and this is exacerbated by the apparently indiscriminate distribution of lung metastases throughout the body. Mediastinoscopy should be performed to rule out the possibility of subclinical N2 or N3 involvement. Imaging techniques such as CT scans, ultrasound and isotope bone scans are useful if there is any clinical evidence for involvement in the brain, liver or skeleton. Suspected metastases in the skin and lymph nodes may be investigated by biopsy.
