lung%20cancer
LUNG CANCER
Lung cancer is having a malignant tumor in the lungs especially in the cells lining air passages.
Primary tumor-related signs and symptoms are cough, dyspnea, hemoptysis, and chest discomfort.
Signs and symptoms due to intrathoracic spread may involve the nerves (hoarseness, dyspnea, muscle wasting of upper limb, Horner's syndrome), chest wall and pleura (chest pain, dyspnea) and vascular structures (facial swelling, dilated neck veins, cardiac tamponade) & viscera (dsyphagia).
The signs and symptoms due to metastatic spread are bone pain with or without pleuritic pain, neurologic symptoms, limb weakness, unsteady gait, cervical lymphadenopathy, and skin nodules.

Epidemiology

  • The leading cause of cancer death worldwide and the 2nd most common cancer in both men and women 
  • It was estimated that 80-90% of all lung cancer cases are due to tobacco or cigarette smoking
    • Approximately 50% of lung cancer cases are from active smokers and approximately 15% are from second-hand smoke exposure during childhood and adolescence

Definition

  • Lung cancer develops when cells inside the lungs (lining of the bronchi) begin to grow out of control, invade nearby tissues and metastasize

Signs and Symptoms

Primary Tumor-Related

  • Cough, dyspnea, hemoptysis, fever, wheezing

Due to Intrathoracic Spread

  • May involve the nerves (hoarseness, dyspnea, muscle wasting of upper limb, Horner’s syndrome), chest wall and pleura (chest pain, dyspnea), vascular structures (facial swelling, dilated neck veins, cardiac tamponade) and viscera (dysphagia)


Due to Metastatic Spread

  • Bone pain with or without pleuritic pain, neurologic symptoms, limb weakness, unsteady gait, cervical lymphadenopathy, skin nodules


Paraneoplastic Syndromes

  • Hypercalcemia (nausea or vomiting, abdominal pain, constipation, polyuria, thirst, dehydration, confusion, irritability)
  • Syndrome of inappropriate antidiuretic hormone (SIADH) production (malaise, weakness, confusion, seizures, volume depletion, nausea, decreased level of consciousness, coma)
  • Cushing’s syndrome (weakness, muscle wasting, decreased level of consciousness, confusion, psychosis, dependent edema, hypokalemic alkalosis, hyperglycemia, weight gain, moon facies, hypertension)
  • Others (digital clubbing, hypertrophic osteoarthropathy, Eaton-Lambert myasthenic syndrome, peripheral neuropathy, cortical cerebellar degeneration, Trousseau's syndrome)

Other Symptoms

  • Malaise, loss of appetite and weight loss

Risk Factor Assessment

Patient Factors
  • Patients ages 65 years old and above (average is 70 years old) are at a greater risk of lung cancer development
  • Smoking cigarettes increases the risk of developing lung cancer
    • Number of packs of cigarettes smoked per day and the years spent smoking is directly related to the development of lung cancer
    • Patients aged 55-77 years with a ≥30 pack-year smoking history and individuals with 30 pack-year smoking history who quit <15 years ago belong to the highest-risk group of lung cancer
  • Passive smokers have 24% increased risk of developing lung cancer
  • Occupational and environmental exposures
    • Asbestos, arsenic, beryllium, chloromethyl ether, chromium, nickel, polycyclic aromatic hydrocarbons, vinyl chloride, radon, cadmium, diesel exhaust fumes, coal smoke and soot, talc, uranium
  • Previous lung disease (eg chronic obstructive pulmonary disease with FEV1 ≤70% predicted, pulmonary fibrosis)
  • History of any cancer, thoracic radiation or alkylating agents
    • Risk of cancer due to radiation is proportional to the dose received and usually starts approximately 20 years after exposure
  • Family history of lung cancer
  • Beta carotene supplements in heavy smokers
  • Exposure to infectious agents: Human immunodeficiency virus (HIV), fungal infections, tuberculosis, aspiration, infectious respiratory symptoms
  • Survivors of lung cancer, lymphomas, cancers of the head and neck or smoking-related cancers
Radiologic Factors
  • Associated with scarring or suspicion of inflammatory changes
  • Fluorodeoxyglucose (FDG) avidity (PET scan) 
  • Size, shape and density of the pulmonary nodule 
Physical Examination
  • The 2 important factors that predict the survival of patients following treatment are weight loss and performance status
  • Patients who lost <10% of their pre-treatment weight and are mobile have better chances of survival
Laboratory Tests
  • Should include electrolytes, liver function tests (LFTs), calcium, lactate dehydrogenase (LDH), blood urea nitrogen (BUN), creatinine 
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