Lung cancer, a silent killer | Sunday Observer
One of the most preventable cancers worldwide

Lung cancer, a silent killer

There has been a sharp rise in lung cancer in recent years worldwide and in Sri Lanka, with the dubious distinction of being the commonest cancer in many countries and the second commonest cancer among males in our country. Recent National Cancer Incidence data shows evidence of the fact that the vast majority of new cases of lung cancer patients reported in Sri Lanka are males. Regrettably, the majority of them are fairly young males, many the sole bread-winners of their families whose untimely death has left them in dire socio-economic straits.

Smoking tobacco or tobacco related products is one of the main causes leading to lung cancer. Ask any patient when or why he started this unhealthy habit of smoking, and in most instances he will tell you that it is because of peer pressure, or because others were doing it. None of them, however, realise the lasting damage that cigarette smoke will do to his lungs leading to scars that remain for life and untimely death. Nor do they realise that by exposing their loved ones to second hand smoke could expose them to this dreaded disease.

The good news is that the risk of lung cancer can be reversed just by quitting smoking- altogether.

Community Physician, National Cancer Prevention Programme (NCPP) Dr Nayana De Alwis spoke to the Sunday Observer on what lung cancer is, the main causes for it and how it could be prevented by following some simple rules.


Q. Although the lung is a small organ in our body, many people still don’t know what it looks like or its function. What is the normal structure and function of the lungs?

Dr Nayana De Alwis

A. Lungs are two sponge like organs within the chest. The right lung has three lobes and left lung has two lobes. The left lung is smaller because the heart takes up more room on the left side of the chest.

The main functions of the lungs are taking oxygen in and getting rid of carbon dioxide from the body. Air entering through the mouth or nose goes into the lungs via the trachea (windpipe).

The trachea divides into tubes called bronchi which enter the lungs and further divided into smaller bronchioles. These bronchioles end into small air sacs within the lung known as alveoli.

Oxygen in the inhaled air which enters the alveoli is absorbed into the small blood vessels surrounding each alveolus. At the same time the carbon dioxide within these blood vessels enter the alveoli and get rid of them from the body through exhalation.

Q. Although Lung cancer is now regarded as one of the commonest cancers worldwide and in Sri Lanka, many people still do not know what exactly it is. Can you tell us what it is?

A. Lung cancer is a type of cancer that occurs in the cells of the lungs. Cancer causing substances (carcinogens) damage the cells lining the lungs.

In the initial stages, these dying cells are removed and replaced by the formation of new cells as and when required.

However, with repeated exposure more normal cells die and the body has to replace these cells by proliferating more and more cells. In this kind of rapid proliferation, chances of producing abnormal cells are high. Cancer starts when abnormal cells in the body begin to grow out of control and in a purposeless manner.

When there are lots of abnormal cells, the body cannot control their proliferation and ultimately it leads to the development of a cancer.

Lung cancer is the most common cancer in many countries while it is the 2nd commonest male cancer in Sri Lanka. In 2014, there were 1,316 new lung cancer patients reported in Sri Lanka. Of them 1,032 were male patients.

Q. What are the risk factors for lung cancer?

A. A risk factor is anything that increases the person’s chance of getting a disease such as cancer. Different cancers have different risk factors.

Tobacco smoke – smoking is by far the leading risk factor for causation of lung cancer. The risk of lung cancer for smokers is many times higher than for nonsmokers.

The risk depends on the duration of smoking and the number of sticks/packets smoked per day. If both are high the risk is greatest. Cigar smokers and pipe smokers are almost at the same risk of developing lung cancer as cigarette smokers.

Q. Can someone who does not smoke be exposed to the danger of lung cancer?

A. If someone who does not smoke, is still breathing the smoke of others who smoke in close vicinity, we call it Second Hand Smoking or Passive Smoking. Studies have proved that passive smokers also have an increased risk of lung cancer probably at the same intensity as smokers.

Q. What other factors can contribute to lung cancer?

A. 1. Previous radiation therapy. If a person had undergone radiation therapy to the chest area as a treatment modality for other disease condition (eg; some other cancer) he has a higher chance of developing lung cancer later in life.

Q. Family history of lung cancer, how high is it on the risk list?

A. If a first degree relative develops lung cancer especially at a younger age, there is a possibility of increased risk among family members.

However, it is not clear how much of this risk might be due to shared genes among family members and how much might be from shared household exposures to carcinogen.

Q. What about exposure to harmful chemicals at workplaces?

A. Workplace exposure to carcinogens can increase the risk of developing lung cancer especially, workers who are smoking as well.

Q. Any other contributory factors?

A. Radon exposure. Radon is a naturally occurring radioactive gas released to the air due to the breakdown of uranium in soil and rocks..

Chemicals such as arsenic, beryllium, cadmium, silica, vinyl chloride, nickel compounds, chromium compounds, coal products, mustard gas and chloromethyl ether emitted to the environment as industrial by-products or any other means can increase the risk of lung cancer.

Q. What about air pollution which is now common in most cities and towns leaving permanent smogs? Can it lead to lung cancer?

A. Exposure to other carcinogens in the air which could be indoor or outdoor can increase the risk of lung cancer.

Air pollution – due to the outdoor burning of some waste materials which release carcinogens eg: burning of polythene and plastics release chemicals including dioxin to the environment leading to cancer.

Q. Any other factors worth mentioning?

A. Exposure to diesel exhaust – exhaust from diesel engines contains complex mixture of soot and gases. People exposed to diesel exhaust on a regular basis can have health problems including cancer, lung and heart diseases

* Exposure to asbestos fibres – people working with asbestos such as workers in mines, mills, textile plants, places where insulation is taking place and shipyards are at higher risk of developing lung cancer compared to the general public.

Asbestos is still present in homes and other buildings but, it is not harmful as long as it is not released to the air by deterioration, demolition or renovation.

Q. What are the signs and symptoms of lung cancer? Are they visible at the early stages?

A. Usually signs and symptoms of lung cancer do not appear until the advanced stage.

Even when symptoms appear at an early stage, people ignore them thinking they are not serious and relate to some other condition. This may delay the diagnosis.

Most of the signs and symptoms mentioned below can be found in other disease conditions than lung cancer. However, one should seek medical advice if one developed these symptoms especially people having risk factors.

* Persistent cough that doesn’t go away or gets worse

* Coughing up blood or rust coloured sputum (spit or phlegm)

* Difficulty in breathing (short of breath)

* Chest pain often worse with deep breathing, coughing and laughing

* Changes in the voice (hoarseness)

* Loss of appetite

* Unintentional weight loss

* Feeling tired or weak

* Recent onset of wheezing

Q. If lung cancer spreads to other parts of the body what kind of symptoms indicate this?

* Bone pain.

* Symptoms in the nervous system (headache, weakness or numbness of a limb, dizziness, seizers) due to the spread to brain

* Yellow discolouration of skin and eyes due to involvement of liver

* Lymph node involvement such as those in the neck or above the collarbone.

Q. Prevention- how do we prevent it?

A.Lung cancer cannot be detected at early stages and there are no screening programs to detect it early. Therefore, prevention is the key to control lung cancer.

Q. Mention some of the strategies the NCCP recommended to the public to prevent lung cancers?

A. Following are some of the identified strategies:

* Don’t smoke – If you have never smoked, do not start.

* Stop smoking – stop smoking as soon as possible, quitting will decrease the risk of lung cancer even if you have smoked for years

* Avoid second hand smoke – Both in work and home environment you have the right to protest someone smoking at close vicinity. Avoid areas where people smoke

* Avoid carcinogens at work – take precautions to protect yourself from exposure to toxic chemicals at work. If you are given protective equipment, wear them properly at work. Risk of lung damage is more for workers who smoke.

Following lifestyle habits will help reduce the risk of cancers as well as other non-communicable diseases (diabetes, hypertension, heart diseases etc..)

* Consume healthy diet. Diet containing a variety of fruits and vegetables and avoid unhealthy foods as much as possible.

* Regular physical activity – regular physical activity will help to prevent many cancers including lung cancer