Lung Cancer – the signs, causes & risks

Lung cancer starts in the tissues of the lungs or the cells that line the bronchi. These are the tubes that move air into and out of the lungs. There are two main types of lung cancer:

Small Cell Lung Cancer (SCLC)

SCLC is an aggressive form of lung cancer that typically starts in the bronchi and spreads very quickly to other parts of the body. It's uncommon for people who have never smoked to get it.

Non-Small Cell Lung Cancer (NSCLC)

About 85 percent of people with lung cancer have NSCLC. This type of cancer tends to spread slowly. It's very common amongst smokers.

Causes and Risk Factors

  • Smoking tobacco is the number one risk factor for lung cancer. Even smoking cigars or a pipe can cause cancer.
  • Secondhand smoking, which is inhaling the smoke from other people's cigarettes, pipes or cigars, also is a risk factor.
  • Another cause is genetics, such as a family history of lung cancer.
  • Frequent environmental exposure to asbestos, radon, certain heavy metals, traffic exhaust and other chemicals can also lead to this disease.

Signs and Symptoms

Lung cancer symptoms differ from person to person, and generally don’t appear until the cancer has advanced to a stage where it's challenging to treat - one of the main reasons lung cancer survival rates are worse compared to other types of cancers.

Common symptoms are:

  • A consistent cough that gets worse over time
  • Hoarseness
  • Dull, aching or persistent chest pain
  • Shortness of breath
  • Coughing up blood
  • Frequent lung infections like bronchitis or pneumonia

There are also symptoms, which are not related the lungs or breathing. These include:

  • Sudden weight loss
  • Loss of appetite
  • Constant Headaches
  • Bone pain or fractures
  • Blood clots

Lung Cancer Screening

Yearly lung cancer screening for people between the ages of 55 and 80 is recommended by most medical organisations. It is highly advised for people who are currently smoking or have quit smoking within the past 15 years.

Screening helps detect early signs before a person shows any symptoms. There are a number of tests done to diagnose and rule out lung cancer. These include:

  • Imaging Tests - The doctor can detect abnormal masses or spots on the lungs by doing a chest X-ray, CT Scan or PET Scan. 
  • Lung Biopsy - This involves taking a small amount of fluid or tissue from the lungs, in order to detect cancer cells under a microscope.