Lung Cancer: Diagnosis

Primary Symptoms

Lung cancer has an insidious onset, and the disease is usually well developed by the time of diagnosis. Clinical signs and symptoms that suggest lung cancer are:

• Generalized weakness and fatigue. 
• Cough. About 93% of lung cancer patients complain of an initial cough, which gradually worsens. Chronic irritation of the bronchial epithelium will cause a persistent cough that can be dry, productive, spastic, and refractory to symptomatic treatment. When the tumor erodes the lung capillaries, the cough is often accompanied by hemoptysis.
• Chest pain, which is often pleuritic. This commonly occurs when the tumor invades the pleural folds or the thoracic wall and ribs, causing pleural effusion.
• Loss of weight and appetite.
• Persistent fever.
• Clubbing of fingers and toes.
• Dyspnea. This is a late symptom, caused by airway obstruction or compression.
• Atelectasis.
• Lymphadenopathy in the axilla, latero–cervically, or supraclavicularly.
• Hoarseness. This symptom is caused by the compression of the laryngeal recurrent nerve in the mediastinum by the tumoral growth.
• Dysphagia. It occurs when the tumor invades or compresses the esophagus.
• Pericardial complications. These are frequent and due to direct invasion and metastatic spread.
• Recurring infections, such as bronchitis and pneumonia, with moderate fever.

Metastatic Symptoms

Signs and symptoms vary according to the organ or site affected.

• Bone pain and limitations of use occur with bony metastases.
• Neurological changes (such as weakness or numbness, dizziness, or recent seizure onset) occur when tumors invade or compress nerves. 
• Jaundice results from metastatic invasion and/or compression of the liver and biliary canals.
• Masses may appear near the surface of the body due to cancer spreading to the skin or to regional lymph nodes.

Laboratory Tests and Clinical Procedures

Chest x–ray can detect lesions up to 2 years before symptoms appear. It defines tumor size and location and can track progression or remission.

Bronchoscopy facilitates diagnosis through tissue biopsy. Bronchoscopic lavage allows for cytologic and histologic analysis, which can detect cancer before radiologic changes.

Computed tomography (CT) accurately reveals tumor location and size.
CT–guided percutaneous fine–needle aspiration of pulmonary nodules allows for cytological examination.

Erythrocyte sedimentation rate (ESR) is usually elevated in malignant disease. It is a nonspecific finding, however, as ESR is also commonly elevated in tuberculosis and other pulmonary infections.

Ultrasound examination allows differentiation of cystic versus solid tumors. It also allows guidance of thoracentesis needle.

Radioactive pulmonary scan, with radioisotopes injected into the bloodstream, is better than x–ray for precise and extended visualization of tumoral lesions.

Bronchography with contrast dyes allows visualization of distal bronchi, stenosis, and infarcts.

Phlebography allows visualization of axillary or subclavicular enlarged lymph nodes. Phlebography through the vena cava and azygos vein reveals mediastinal compression and infiltration.

Pleuracentesis gives the diagnosis in 80% of cases where pleural invasion occurs.

Lymph node biopsy is of great diagnostic value when enlarged lymph nodes are present and accessible.

Mediastinoscopy allows for a biopsy of hilar and mediastinal ganglia and is positive in nearly 40% of all lung cancer cases. It allows direct visualization of possible mediastinal invasions that could contraindicate surgery.