Lung Cancer: Diagnosis, causes & risks

As you know, lung cancer is a serious disease that's generally the result of smoking. However, even non-smokers are at risk. That's because lung cancer can result from a lifetime of exposure to many things all around us.

In fact, there are lots of other causes that would also make doctors look at, or screen, people more closely because they may be at risk. After a screening, some people may need to undergo more tests. This helps the healthcare team make the correct diagnosis and know which treatment approach is best for you.

There are more than 13,000 new cases of Lung Cancer each year in the Philippines

Causes and risk factors

People may be at risk of lung cancer depending on their type of industry or workplace, such as mines, mills, or some textile plants.

Some other causes of cancer include

  • Asbestos
  • Radioactive minerals such as uranium and radon
  • Inhaling certain chemicals or compounds such as arsenic, coal products, vinyl chloride, among others
  • Overexposure to diesel exhaust

Fortunately, there have been updated regulations and policies to protect workers and improve safety in the workplace. If you work in this type of environment, it's always a good idea to have routine check-ups with your doctor.

Signs & symptoms

The Centers for Disease Control and Prevention (CDC) have guidelines that make it easier to determine who should be screened based on their risk of lung cancer. But every case of lung cancer is unique, so symptoms may vary from patient to patient. What's more, by the time symptoms are noticed, the lung cancer may be in an advanced stage. To learn more about how lung cancer progresses, please see the section "Staging lung cancer."

When lung cancer is found early, it's often found by chance. A person may be treated for another condition, or having a routine procedure, when the doctor may notice something unusual on a chest x-ray or other diagnostic test. When lung cancer is diagnosed this early, there are more treatment options.

Lung cancer symptoms seen may include, but are not limited to:

  • coughing a lot
  • pain in the chest that gets worse with coughs, breathing, or laughing
  • ache or pain in shoulder, back, or chest
  • losing weight, not being hungry
  • trouble catching your breath
  • coughing up spit or phlegm with blood in it
  • being tired
  • wheezing

Always see your doctor if you have any concerns. They will know how to help guide you through the next steps.

Screening for lung cancer

A screening is when a doctor looks for signs of lung cancer before any symptoms appear. If cancer is discovered early, there are more options for treatment as well as a better outlook. At the moment, there's only one test that's recommended for lung cancer screening. It's called a low-dose computed tomography (LDCT). An x-ray machine uses small amounts of radiation to create detailed scans of the lungs.

The CDC has guidelines in place to help doctors determine who may be at risk. These include people who:

  • Have a history of heavy smoking, and
  • Smoke now or have quit within the past 15 years, and
  • Are between 55 and 80 years old

According to the CDC, heavy smoking means that the person has smoked a pack of cigarettes a day for a year for 30 years or two packs of cigarettes a day for 15 years. If a person meets these guidelines, a lung cancer screening test should probably be done.


If a screening shows something that doesn't look right, the healthcare team will do more tests to investigate. This way, the team can make a more accurate diagnosis and, if need be, get treatment started. Some diagnostic tests are:

Sputum cytology

Here, mucus (or sputum) is coughed up from the lungs. Then some of it is put under a microscope to see if there are any abnormal cells. This test is useful for finding tumors that may be growing in the airways of the lungs.

Computed tomography (CT) scan

Also called a CAT scan, this test is like having an x-ray. It lasts a little bit longer because it takes lots of pictures from many different angles. The CT scanner does this by moving in a circular motion around the body as the person lies still on a table. The person being tested usually needs to have a contrast solution (a mixture that helps create detailed images of the lungs and other soft tissues like lymph nodes) in their body first. The doctor will decide whether they drink it or if it goes into their body through a vein. Doctors get a lot of important information from this test such as where and how big the cancer is.


For an even closer examination of the abnormal growth, a small sample is removed by either: a needle; a long thin tube; or surgery. This way, doctors can view it under a microscope.

Mutation tests

Mutation tests (also known as molecular profiling) are very specific and look for certain changes in a person's cancer genes. In these cases, your treatment team takes a small piece of the cancer and runs tests on it to see if a targeted drug therapy could be effective in fighting the specific cancer cells. Note that not all cancers will be right for this type of treatment.

Healthcare teams have several options in diagnosing lung cancer, but often use one of two ways, invasive or non-invasive.

  • Invasive procedures mean that there is a break in the skin or something enters a body cavity, like through your mouth

Non-invasive procedures refer to those for which there is no break in your skin or entry into a body cavity


  1. GLOBOCAN 2012: Estimated Cancer Incidence, Mortality and Prevalence Worldwide in 2012. Lung Cancer.