Lung cancer is the most common cancer in the world. There were apparently 1.8 million new cases in 2012 (12.9% of the total), 58% of which occurred in less developed regions.
The disease is more common in men worldwide (1.2 million, 16.7% of the total). In women, the incidence rates are generally lower and the geographical pattern is a little different, mainly reflecting different historical exposure to tobacco smoking. Thus the highest estimated rates are in Northern America (33.8) and Northern Europe (23.7) with a relatively high rate in Eastern Asia (19.2).
Lung cancer is the most common cause of death from cancer worldwide, estimated to be responsible for nearly one in five (1.59 million deaths, 19.4% of the total) deaths.
Common cancer in Malaysia
In Malaysia, lung cancer continues to be a leading cause of death. In 2007, lung cancer was the third most common cancer after breast and colorectal cancers. In males, it is the first on the list and the fifth in females.
There are two major types of lung cancer – non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) which is less common. Other types of cancer found in the lungs are carcinoid and lymphoma.
Most lung cancer is caused by smoking (90%), and this includes both active and second-hand smoking. Tobacco smoke contains more than 4,000 chemical substances, most of which have been identified to cause lung cancer. According to research smoking 20 cigarettes per day increases the risk of lung cancer by 20-25 times compared to non-smokers.
When a smoker quits smoking, the risk of lung cancer is reduced. After quitting for 15 years, the risk of getting lung cancer is the same as non-smokers. Cigar and pipe smoking also increase the risk of developing lung cancer.
Other causes of lung cancer include air pollution from vehicles and factories, exposure to asbestos, and having lung diseases such as tuberculosis and chronic obstructive pulmonary disease. In addition, occupational exposure to arsenic, chromium, nickel, aromatic hydrocarbon and ether also increases the risk of developing lung cancer.
In the early stages, lung cancer may not cause any symptoms, but common symptoms include persistent cough, chest pain, shortness of breath, hoarseness of voice, coughing out of blood, loss of appetite and weight, excessive lethargy and recurrent chest infection.
At present, there is no cost effective method to detect early lung cancer and individuals usually present symptom at a late stage. As such, the most effective method to prevent lung cancer is to quit smoking or reduce exposure to tobacco smoke whether active or passive (second-hand smoke).
Cancer screening in lung cancer is still controversial, although early detection at an early stage of lung cancer can lead to a more effective treatment.
To diagnose lung cancer, a doctor could perform a combination of tests including blood investigations, sputum examination, chest X ray, computerised tomography (CT) scan of the thorax, bronchoscopy, pleuroscopy, Positron Emission Tomography (PET) scan (to detect cancer and metastases), bone scan, mediastinoscopy and lung function tests.
Beacon Hospital offers comprehensive Health Screening packages that are tailor made for individuals depending on the patient’s needs.
Treatment of lung cancer depends on the type of cancer, stage of cancer and the type of key cause.
Non-small-cell lung cancer
Surgery is mostly used to treat non-small-cell lung cancer. But surgery might not be suitable of the cancer is very near any of the following structures:
- the heart
- the windpipe
- the food pipe (oesophagus)
- major blood vessels
In this situation, the doctor might recommend other cancer treatments instead of surgery, such as radiotherapy, chemotherapy or a combination of both.
Small cell lung cancer
Surgery is not normally used to treat small cell lung cancer, unless it is at a very early stage. Small cell lung cancer has usually spread beyond the lung when it is diagnosed and so it is not possible to remove it all with surgery. It is more common to have chemotherapy and radiotherapy rather than surgery for small cell lung cancer.
Chemotherapy means using anti-cancer (cytotoxic) drugs to destroy cancer cells. These work by disrupting the growth of cancer cells. Chemotherapy is the main treatment for small cell lung cancer. Doctors use it because:
- this type of cancer responds very well to chemotherapy
- small cell lung cancer tends to have spread beyond the lung when it is diagnosed
Chemotherapy drugs circulate in the bloodstream around the body. So they can treat cells that have broken away from the lung tumour and spread to other parts of the body.
We offer two primary types of radiation therapy for lung cancer:
- External beam radiation therapy (EBRT): Delivers high doses of radiation to lung cancer cells from outside the body, using a variety of machine-based technologies.
- High-dose rate (HDR) brachytherapy (internal radiation): Delivers high doses of radiation from implants placed close to, or inside, the tumor(s) in the body.
The U.S. Food and Drug Administration (FDA) has approved the checkpoint inhibitor drugs pembrolizumab (Keytruda®) and nivolumab (Opdivo®) to treat non-small-cell lung cancer. Pembrolizumab and nivolumab target the PD-1 cell receptor, which helps to regulate immune response.
Immunotherapy may not be recommended for all patients, and responses to the treatment may vary widely. Immunotherapy may also be used in combination with other treatments such as surgery or chemotherapy. For instance, pembrolizumab has been approved by the FDA to be a first-line treatment in combination with chemotherapy in some cases of non-small-cell lung cancer.
Dr. Mani, Beacon Hospital Malaysia