What Are the Risk Factors of Lung Cancer?

Reviewed on 5/20/2021

The different types of lung cancer include non-small cell lung cancer, small cell lung cancer, and other types of lung tumors. Smoking is the main cause of lung cancer. Other causes of lung cancer for non-smokers include secondhand smoke, air pollution, exposure to radon, radiation therapy, workplace exposure to carcinogens, genetic changes, and arsenic in drinking water.
The different types of lung cancer include non-small cell lung cancer, small cell lung cancer, and other types of lung tumors. Smoking is the main cause of lung cancer. Other causes of lung cancer for non-smokers include secondhand smoke, air pollution, exposure to radon, radiation therapy, workplace exposure to carcinogens, genetic changes, and arsenic in drinking water.

Lung cancer is a type of cancer that occurs when lung cells become abnormal and grow out of control. 

The different types of lung cancer are outlined in the table below.

Lung Cancer Types
Cancer Type Characteristics
Non-small cell lung cancer 
  • The most common type of lung cancer
  • Accounts for 80% to 85% of cases
Small cell lung cancer (also called oat cell cancer) 
  • Accounts for 10% to 15% of cases
Other types of tumors that can form in the lungs
  • Lung carcinoid tumors account for fewer than 5% of lung tumors
  • Other lung tumors: adenoid cystic carcinomas, lymphomas, and sarcomas, and benign lung tumors such as hamartomas are rare

The main cause and risk factor for all types of lung cancer is smoking, which is responsible for 80% of all lung cancer deaths, as well as many deaths from exposure to secondhand smoke

Smokers exposed to radon and asbestos are at higher risk, as are smokers who take beta-carotene supplements

In non-smokers, risk factors for lung cancer include:

  • Secondhand smoke
  • Air pollution
  • Exposure to radon
  • Radiation therapy to the chest for other cancers
  • Workplace exposure to carcinogens 
    • Asbestos
    • Diesel exhaust
    • Radioactive ores such as uranium
    • Inhaled chemicals such as arsenic, beryllium, cadmium, silica, vinyl chloride, nickel compounds, chromium compounds, coal products, mustard gas, and chloromethyl ethers
  • Genetic changes
  • Arsenic in drinking water (seen in parts of Southeast Asia and South America; drinking water is not a major source of arsenic in the U.S.) 

Factors with uncertain or unproven effects on lung cancer risk include: 

  • Smoking marijuana
  • E-cigarettes
  • Talc and talcum powder

What Are Symptoms of Lung Cancer?

Lung cancer may not have symptoms early on. When the first signs and symptoms do occur, they may include:

  • Persistent or worsening cough
  • Coughing up blood or rust-colored sputum
  • Shortness of breath
  • Breathing problems
  • Chest pain that may be worse with deep breathing, coughing, or laughing
  • Hoarseness
  • Loss of appetite
  • Unexplained weight loss
  • Fatigue/tiredness
  • Weakness
  • Wheezing
  • Respiratory infections such as bronchitis and pneumonia that don’t go away or recur

How Is Lung Cancer Diagnosed?

Symptoms of lung cancer often do not appear until the cancer is advanced. For this reason, The American Cancer Society has lung cancer screening guidelines for people with a higher risk of getting lung cancer, such as smokers. 

The American Cancer Society recommends people who are 55 to 74 years old, are in fairly good health, are current smokers or who have quit in the past 15 years, and have smoked a certain number of cigarettes per day should receive regular lung cancer screenings. A test called a low-dose CAT scan or CT scan (LDCT) is typically used. 

If lung cancer is suspected, imaging tests may be used to diagnose it, such as:

Lab tests used to diagnose lung cancer include:

  • Sputum cytology 
  • Thoracentesis 
  • Tissue biopsy 
  • Bronchoscopy masses
  • Endobronchial ultrasound 
  • Endoscopic esophageal ultrasound
  • Mediastinoscopy and mediastinotomy
  • Thoracoscopy
  • Lung function tests
  • Molecular tests for gene changes 
  • Tests for certain proteins on tumor cells
  • Blood tests

QUESTION

Lung cancer is a disease in which lung cells grow abnormally in an uncontrolled way. See Answer

What Is the Treatment for Lung Cancer?

Treatment for lung cancer depends on the stage, and may include:

  • Surgery
    • Removal of the tumor (stage 0)
    • Removal of the lobe of the lung that has the tumor (lobectomy) or removal of a smaller piece of the lung (sleeve resection, segmentectomy, or wedge resection) (Stage 1)
    • Lobectomy or sleeve resection or removal of the entire lung (pneumonectomy) (Stage 2 and later stages)
  • Photodynamic therapy (PDT)
  • Laser therapy
  • Adjuvant chemotherapy 
  • Radiation therapy
  • Radiofrequency ablation (RFA) 
  • Lymph node removal
  • Chemotherapy 
  • Targeted therapy 
  • Immunotherapy with pembrolizumab (Keytruda) or durvalumab (Imfinzi)
  • Participation in clinical trials

Stage IV lung cancers are widespread and very hard to treat and cure. Any of the above treatments may be used to help patients live longer, but they are unlikely to cure the disease at this stage. 

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Reviewed on 5/20/2021
References
https://www.cancer.org/cancer/lung-cancer.html

https://www.cdc.gov/cancer/lung/basic_info/risk_factors.htm