Lung Cancer
The most common forms of lung cancer are squamous cell (epidermoid) carcinoma, small-cell (oat cell) carcinoma, adenocarcinoma, and large-cell (anaplastic) carcinoma. The most common site is the wall or epithelium of the bronchial tree.
For most patients, the prognosis is poor, depending on the cancer’s extent when diagnosed and the cells’ growth rate. Only about 13% of patients with lung cancer survive 5 years after diagnosis.
Lung cancer is the most common cause of cancer death in males and is fast becoming the most common cause of cancer death in females.
Lung cancer is the most common cause of cancer death in males and is fast becoming the most common cause of cancer death in females.
Causes
Lung cancer’s exact cause remains unclear. Risk factors include tobacco smoking, exposure to carcinogenic and industrial air pollutants (such as asbestos, arsenic, chromium, coal dust, iron oxides, nickel, radioactive dust, and uranium), and genetic predisposition.
Complications
Disease progression and metastasis cause various complications. When the primary tumor spreads to intrathoracic structures, complications may include tracheal obstruction, esophageal compression with dysphagia, phrenic nerve paralysis with hemidiaphragm elevation and dyspnea, sympathetic nerve paralysis with Horner’s syndrome, eighth cervical and first thoracic nerve compression with ulnar and Pancoast’s syndrome (shoulder pain radiating to the ulnar nerve pathways), lymphatic obstruction with pleural effusion, and hypoxemia. Other complications are anorexia and weight loss, sometimes leading to cachexia; digital clubbing; and hypertrophic osteoarthropathy. Endocrine syndromes may involve production of hormones and hormone precursors.
Assessment
Because early lung cancer may cause no symptoms, the disease may be advanced when it’s diagnosed. While taking the patient’s history, be sure to assess his exposure to carcinogens. If he’s a smoker, determine pack years.
The patient’s chief complaints may include coughing (induced by tumor stimulation of nerve endings), hemoptysis, dyspnea (from the tumor occluding air flow) and, sometimes, hoarseness (from tumor or tumor-bearing lymph nodes pressing on the laryngeal nerve).
On inspection, you may notice the patient become short of breath when he walks or exerts himself. You may also observe finger clubbing; edema of the face, neck, and upper torso; dilated chest and abdominal veins (superior vena cava syndrome); weight loss; and fatigue.
Palpation may reveal enlarged lymph nodes and an enlarged liver. Percussion findings may include dullness over the lung fields in a patient with pleural effusion.
Auscultation may disclose decreased breath sounds, wheezing, and pleural friction rub (with pleural effusion).
Diagnostic tests
Chest X-rays usually show an advanced lesion and can detect a lesion up to 2 years before signs and symptoms appear. Findings may indicate tumor size and location.
Cytologic sputum analysis, which is 75% reliable, requires a sputum specimen expectorated from the lungs and tracheobronchial tree, not from postnasal secretions or saliva.
Bronchoscopy can identify the tumor site. Bronchoscopic washings provide material for cytologic and histologic study. The flexible fiber-optic bronchoscope increases test effectiveness.
