Lung Cancer: Causes, Symptoms, Diagnosis and Treatment

Related Oncology Clinic | Date May 14, 2019

Lung cancer occurs from the cells of the lung tissue that divide quickly, unusually and uncontrollably until it becomes a lung tumor that grows and spreads rapidly to nearby or other organs.

Tobacco smoke is made up of thousands of chemicals, including at least 70 known to cause cancer. Eighty percent of lung cancer patients are regular smokers who have been smoking for a long period of time. Smoking causes the majority of lung cancers – both in smokers and in people exposed to secondhand smoke. The remaining cases are caused by external risk factors such as inhaling volatile chemicals or substances mixed with heavy metals or continuous exposure to radiation.

The most common symptoms of lung cancer are:

  • A cough that does not go away or gets worse
  • Coughing up blood or rust-colored sputum (spit or phlegm)
  • Chest pain that is often worse with deep breathing, coughing, or laughing
  • Hoarseness
  • Weight loss and loss of appetite
  • Shortness of breath
  • Feeling tired or weak
  • Infections such as bronchitis and pneumonia that don’t go away or keep coming back
    New onset of wheezing

Lung cancer is diagnosed using imaging studies to locate the suspicious lesion and identify the cancer cells in those lesions. Early detection of lung cancer is most effective for reducing mortality. The American Cancer Society recommends annual lung cancer screening with a low-dose CT scan for certain people at higher risk for lung cancer who meet the following conditions:

  • Are aged 55 to 74 years and in fairly good health
  • Currently smoke or have quit within the past 15 years
  • Have at least a 30-pack-year smoking history

Quitting smoking reduces your risk of lung cancer, even if you’ve smoked for years. Talk to your doctor about strategies and stop-smoking aids that can help you quit. Options include nicotine replacement products, medications and support groups.





Witthawat Ariyawutyakorn, M.D.
Medical Oncologist