We read and hear often about lung cancer, but surprisingly, it is one of the more misunderstood types of cancer. Many people assume that only smokers will get lung cancer, for example. In this Special Report, we present the facts and address the myths of lung cancer, so that you will be in a better position to understand this unfortunately common medical condition.

Clearing the Air on Our Lungs 

Our lungs are vital. Just how vital? Let’s find out.

Our lungs are comparable to a power plant for our body. With each breath we take, air passes from our trachea – the passage that connects our nose and mouth to the lungs – to the lungs. Meanwhile, the lungs contain a rich network of small blood vessels (or capillaries) in both its lobes. These capillaries form a web over the thin walls of small balloon-like structures called the alveoli (singular: alveolus).

What happens is this: our body needs oxygen for the growth and development of our cells. Oxygen allows us to obtain energy from the food we eat, and this energy powers the many functions of our organs. Oxygen is carried by red blood cells, pumped from the heart to every part of our body through our network of blood vessels.

The oxygen comes from the air we breathe, seeping through the thin walls of the alveoli into red blood cells in the capillaries. Therefore, red blood cells leave the lungs full of oxygen for the rest of our body, while oxygen-depleted red blood cells travel back to the lungs to replenish themselves.

The lungs also remove carbon dioxide from these oxygen-depleted red blood cells. Carbon dioxide is a waste product generated by the metabolic processes of our cells, and it is released from our body with each breath we exhale. Therefore, our lungs also play a role in removing waste products that could impact our health when accumulated in high amounts.

When our lungs break down, our many body functions become impaired due to the lack of oxygen. This is why most lung diseases – especially lung cancer – need to be given medical attention as soon as possible. If left unchecked, they may severely cripple our health and lifestyle – leading to an early death.

In the case of lung cancer, it is a very common killer even in Malaysia. Understanding this cancer, however, would equip us to better lead a healthy lifestyle that would reduce the risk of its occurrence, as well as to empower us to better cope with treatment and management should it happen to us or our loved ones.

Do you know?

• We are born with two lungs, but we can still lead healthy lives if we have only one functional lung. Your ability to carry out physical activities may be more limited compared to when both your lungs were functioning, but some adjustments would allow you to still have a reasonably normal and even active life.
• You can increase your lung capacity (the amount of oxygen your lungs can send to the rest of your body) with regular physical activity.
• Smoking is the primary cause of many lung diseases, including lung cancer. If you smoke and you love your lungs, you really should stop the habit. Consult a doctor or a pharmacist on how you can stop smoking. You can also refer to our Special Report in the August 2015 issue for more information.

Concerning Cancer

Before we take a look at lung cancer, let’s have a quick overview on the meaning of various terms commonly associated with cancer.

Cancer is, basically, what happens when a certain type of cell in our body begin to reproduce and grow in number uncontrollably. Normally, our body has systems to keep such an event under check – cells divide and grow only when needed, and the process stops after a certain number of cells has been reached. When we have cancer, however, something has gone wrong, and the cells just keep growing in size and number.

Tumours

The word “tumour” describes an unusual lump or growth in our body, formed from groups of abnormal cells. Many people assume that a tumour is a sign of cancer, but this is not always the case. There are several types of tumours:

• Benign tumours are non-cancerous, they generally have little effect on our health, and can be surgically removed. 
• Pre-cancerous or pre-malignant tumours are tumours that, while not cancerous, contain cells that may develop into cancer cells some time in the future. It is hard to predict when this may happen – sometimes it takes a short time, sometimes it takes years and even decades, while for other people, these cells may never turn cancerous. Therefore, people with pre-cancerous conditions should go for regular medical check-ups so that further abnormal changes can be quickly investigated and, if necessary, given medical attention.
  • Hyperplasia describes an unusual increase in the number of cells in a certain location of the body. Hyperplastic cells may or may not be pre-cancerous.
  • Atypia is a word used in medical reports for cells that look slightly unusual under the microscope, but such changes could be due to inflammation. More investigaton may be needed.
  • Metaplasia describes unusual-looking cells that are present in a location that they are not normally found at. Usually (but not always), metaplastic cells are not pre-cancerous.
  • Dysplasia describes the abnormal appearance and behaviour of cells at a certain location. Usually, dysplasia suggests that the cells are pre-cancerous.
  • Malignant tumours are cancerous, and there is a chance of a new malignant tumour appearing once one is removed. There is also a risk of metastasis (see below). 

Tumours are usually removed by surgery. However, if the need arises, a doctor may first opt to remove a small tissue from the tumour to be sent to a pathology laboratory for further investigation

Metastasis

Just like how a house packed with too many people may cause some of them to move out, tumour cells may sometimes move to other parts of the body. They can grow and reproduce in those parts, giving rise to new tumours. This process is called metastasis. Common places for new tumours to arise are the lungs, the bones, the brain and liver, although cancer cells can theoretically spread to any part of the body.

When Cancer Strikes

Let’s discover the facts of the common yet deadly lung cancer.  

• Lung Cancer in Malaysia
• 3rd most common cancer in Malaysia.
• 2,100 Malaysians are diagnosed with lung cancer every year.
• 2nd most common cancer affecting Malaysian men. [1]

Who is at risk?

Lung cancer affects people of all ages, but there are some groups whose risk is higher.

• Lung cancer is rare among people under 40, but the risk increases with age. It is most common among people aged 70-74.
• 90% of all cases are attributed to smoking. This is because smokers inhale potentially dangerous chemicals (tar, nicotine, etc) on a regular basis.
• However, non-smokers can still develop lung cancer! This is because there are other possible causes of lung cancer, such as:
• Inhaling other’s people cigarette smoke on a frequent basis.
• Regular exposure to high levels of radon and air pollutants such as asbestos and coal fumes.
• Family history may also play a role.[2],[3] 

Symptoms & Warning Signs

• Persistent cough that either will not go away or just gets worse after 2-3 weeks.
• Coughing is painful, and/or there is blood when you cough.
• Persistent infections of the chest.
• Frequent fatigue, lack of energy and/or breathlessness.
• Loss of appetite or unexplained weight loss
• Less common symptoms include:
• Fingers becoming more curved or club-like (the ends appear larger).
• Fever (38°C or above).
• Difficulty and/or pain in swallowing.
• Swelling of face or neck.
• Persistent chest or shoulder pain.[4]

Two Main Types

When a cancer begins in the lungs, we call such cancer primary lung cancer. There are different types of lung cancer, and the most common is the non-small cell lung cancer (NSCLC).

• Non-small cell lung cancer (NSCLC), which is more common (75-80% of reported cases).4 NSCLC can be grouped as follow:
  • Squamous cell carcinoma, a cancer that develops in the outermost layer of the lung. Often linked to smoking.
  • Adenocarcinoma, a cancer that occurs in the early versions of cells that would eventually become mucus-secreting glands. While often linked to current or past smoking behaviour, it is also a common form of lung cancer among non-smokers.
  • Large cell carcinoma, which can occur in any part of the lung. These cancer cells can metastasize quickly, but such cancer is fortunately less common compared to other types of NSCLC.[5]
  • Other types of lung cancer include small cell lung cancer (SCLC), which is less common but can spread (metastasize) faster. and lung carcinoid tumours, a slow-growing tumour involving a type of cells called the neuroendocrine cells.
  • Different types of cancer are treated differently, so proper diagnosis is important!

Non-Small Cell Lung Cancer (NSCLC)

Like all cancers, NSCLC is caused by a random change in a gene that causes cells to grow in size and number uncontrollable.

• It is found that about 35% of NSCLC patients in East Asia have a mutation in a gene responsible for the creation of a protein called epidermal growth factor receptor (EGFR).
• A gene is divided into smaller segments called exons, and each exon is identified by a number. For the EGFR gene, mutation is found to occur within exons 18 to 21. Common ones include deletion of exon 19 (about 90% of mutations) and point mutation of exon 21L858R. Mutations on exons 18 and 20 are also found in NSCLC patients.
• These mutations result in abnormal changes in EGFR produced, giving rise to NSCLC.
• Interestingly, EGFR mutations are more often found in NSCLC female patients who have never smoked or have smoked less than 100 cigarettes in their lifetime.[6]

Life & Death Matters

• Unfortunately, the outlook for lung cancer is not as good as other cancers, as by the time the symptoms appear, the cancer has usually spread through much of the lungs and even to other parts of the body.6
• About 1-in-3 will live for about a year after diagnosis, and less than 1-in-10 will live for five years or more. Early diagnosis really makes a difference in improving the outlook.6
• However, do not lose hope if you or a loved one is diagnosed with lung cancer; continuous research and development of new drugs over the last few decades could contribute to improved outlook of lung cancer patients. An oncologist could advise you on these options.

Preventing Lung Cancer

Currently there are no methods to completely prevent lung cancer from occurring, but there are some things you can do to lower your risk.

• Don’t smoke. If you smoke, it’s time to quit.
• Avoid contact with second-hand smoke whenever possible, such as sitting in non-smoking areas in restaurants, etc.
• Practice a healthy diet, and increase your intake of fruits and vegetables.
• Exercise regularly, at least 30 minutes a day, and avoid being sedentary whenever possible.[7]

Don’t miss our follow-up Special Report on non-small cell lung cancer (NSCLC), the most common form of lung cancer, and its treatment, available in February 2016. We will share with you the latest medical options available to NSCLC patients, as well as other useful tips and advice.

NHS Choices (UK). Cancer. Retrieved Oct 9, 2015 from http://www.nhs.uk/conditions/cancer/Pages/Introduction.aspx

Canadian Cancer Society. Types of tumours. Retrieved Oct 9, 2015 from http://www.cancer.ca/en/cancer-information/cancer-101/what-is-cancer/types-of-tumours/?region=on

Canadian Cancer Society. How cancer spreads. Retrieved Oct 9, 2015 from http://www.cancer.ca/en/cancer-information/cancer-101/what-is-cancer/how-cancer-spreads/?region=on

[1] National Cancer Society Malaysia. Types of cancer. Retrieved on Oct 9, 2015 from http://www.cancer.org.my/quick-facts/types-cancer/

[2] NHS Choices. Lung cancer. Retrieved on Oct 9, 2015 from http://www.nhs.uk/conditions/Cancer-of-the-lung/Pages/Introduction.aspx

[3] NHS Choices. Lung cancer – causes. Retrieved on Oct 9, 2015 from http://www.nhs.uk/Conditions/Cancer-of-the-lung/Pages/Causes.aspx

[4] NHS Choices. Lung cancer – symptoms. Retrieved on Oct 9, 2015 from http://www.nhs.uk/Conditions/Cancer-of-the-lung/Pages/Symptoms.aspx

[5] American Cancer Society. Lung cancer (non-small cell). Retrieved on Oct 9, 2015 from http://www.cancer.org/cancer/lungcancer-non-smallcell/detailedguide/non-small-cell-lung-cancer-what-is-non-small-cell-lung-cancer

[6] Lovly, C., L. Horn, W. Pao. 2015. EGFR in non-small cell lung cancer (NSCLC). Retrieved on Oct 12, 2015 from http://www.mycancergenome.org/content/disease/lung-cancer/egfr/

[7] Mayo Clinic. Lung cancer: prevention. Retrieved on Oct 9, 2015 from http://www.mayoclinic.org/diseases-conditions/lung-cancer/basics/prevention/con-20025531

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