Lung Cancer 101: Symptoms, Stages, Treatment, Types & Causes

Lung cancer, as the name suggests, happens when cells uncontrollably multiply in the lungs and turn into a tumour. Like other cancers, lung cancer can metastasise or spread in other parts of the body, causing more severe symptoms and needing more intensive treatment.

In Singapore, lung cancer is the 2nd most common cancer in men and the 3rd most common in women. Generally, people who smoke for years have a higher risk of developing lung cancer.

Here’s everything you need to know about lung cancer.

Lung Cancer Symptoms

The symptoms of lung cancer typically do not appear until the condition is in its advanced stage. Symptoms may be confined to respiratory issues or involve other parts of the body, especially when the cancer has already spread. Common lung cancer symptoms include:

• Coughing that worsens and doesn’t go away; it may last for weeks or months.
• Chest pain; the ache sometimes worsens with breathing or coughing.
• Chest infections that come back even after treatment.
• Shortness of breath or persistent breathlessness.
• Coughing up blood.
• Weight loss.
• Loss of appetite.
• A general feeling of weakness or tiredness.

Although rare, the symptoms of lung cancer may also include:

• Wheezing; you may notice a high-pitch whistling sound when you breathe.
• Hoarseness.
• Pain during swallowing (dysphagia).
• Persistent chest or shoulder pain.
• Swelling in the neck or face.

Do keep in mind that these signs may also point to other conditions. Case in point, long-term cough, loss of appetite, weight loss, and coughing up blood are also common symptoms of tuberculosis.

To have the correct diagnosis, it is crucial to consult a doctor as soon as possible. Once in the doctor’s clinic, expect to answer questions about your health history and undergo several tests like chest x-ray, sputum exams, bronchoscopy, and other imaging tests.

If it is indeed cancer, then you can start with the lung cancer staging and treatment right away. This will significantly increase your chances of better long-term outcomes.

Lung Cancer Causes & Risk Factors

According to the American Lung Association, smoking is the number one cause of lung cancer. In fact, it accounts for 90% of all lung cancer cases.

The more years you spend smoking (or getting exposed to second-hand smoke), the higher your lung cancer risk is. Quitting tobacco smoking reduces your risk, but doesn’t eliminate the possibility.

Experts explain that cigarettes contain numerous chemicals that, when inhaled, cause an almost instantaneous change or damage to the lung tissues. Initially, the body may be able to repair the damage. However, with repeated exposure, the extensive damage may trigger our cells to act differently and multiply uncontrollably, eventually leading to cancer.

Besides cigarette smoking, the factors below also increase one’s risk of developing lung cancer:

• Exposure to hazardous chemicals and other carcinogens, such as radon, asbestos, arsenic, and uranium.
• Exposure to particle pollution. Particle pollution refers to the presence of tiny solid or liquid particles in the air we breathe. Examples of these tiny particles are those that come from exhaust smoke.
• Previous radiation therapy on the chest.
• Genes — having a family history of lung cancer puts you at a higher risk of lung cancer.

Types of Lung Cancer

Now that we know more about lung cancer symptoms, causes, and risk factors, let’s talk about the different types of lung cancer.

According to the American Cancer Society, we can divide lung cancer into two primary types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

Non-Small Cell Lung Cancer

The majority of lung cancer cases (80 to 85%) are classified under non-small cell lung cancer or NSCLC. It has several subtypes, including:

• Adenocarcinomas: This subtype typically starts in the cells that produce mucus. Many cases of adenocarcinomas get diagnosed in the outer part of the lungs, usually before they spread. It is a common type of lung cancer in both smokers and non-smokers but occurs more frequently in women than in men.
• Squamous cell carcinoma: Unlike adenocarcinomas that typically start in the outer part of the lungs, squamous cell carcinomas typically begin at the center, near the main airway (bronchus). And it’s not surprising; after all, SCC affects the flat cells that line the airways in the lungs. SCC is highly linked to those who have a history of smoking.
• Large cell carcinoma: This subtype of NSCLC can appear in any part of the lungs. Usually, LCC grows and spreads quickly, which means that it might be more difficult to treat than the other subtypes of NSCLC.

Among all the subtypes of non-small cell lung cancer, the one with the better outlook is adenocarcinoma in situ, or an adenocarcinoma that hasn’t spread yet.

Small Cell Lung Cancer

Also called oat cell cancer, small cell lung cancer or SCLC accounts for 10 to 15% of all lung cancer cases. SCLC tends to grow and spread quickly; in fact, 70% of patients with small-cell lung cancer have cancer that already spread by the time they receive their diagnosis.

Other Types of Lung Tumours

Besides the two primary types of lung cancer, we also have the following type of lung cancer tumours:

• Lung carcinoid tumours: This type of tumour is rare, usually accounting for only 5% of lung tumour cases. Reports say lung carcinoid tumours are made up of cells that produce hormones or hormone-like substances (neuroendocrine cells).
• Other lung tumours: Besides lung carcinoid tumours, other kinds of tumours may occur in the lungs, including lymphoma (cancer in the lymphocytes), sarcoma (cancer in the bones, muscles, etc.), and benign tumours.
• Cancers that spread to the lungs: Some tumours in the lungs are a result of cancer that has metastasised or spread to the lungs from another body part.

Lung Cancer Stages

Lung cancer staging depends on the type of lung cancer.

For instance, if it’s non-small cell lung cancer, the doctor will most probably use TNM staging, which stands for Tumor (its size and location), Node (if cancer has spread to nearby lymph nodes), and Metastasis (if cancer has spread to other body parts).

TNM staging appears as stage 1, 2, 3, or 4 lung cancer. To know more about their differences, refer to the guide below:

• Stage 1: Under this stage, the tumour (usually small) is confined to one lung; it hasn’t spread yet to the lymph nodes and other organs.
• Stage 2: If it’s stage 2, the non-small cell lung cancer tumour is probably bigger (more than 3 centimetres in diameter). It may or may not have affected the lymph nodes, but it still hasn’t metastasised.
• Stage 3: The tumour is larger, usually more than 7 centimetres in diameter. Spread to lymph nodes, especially near the centre of the chest, is possible, but it has not yet metastasised to other organs.
• Stage 4: A stage 4 lung cancer tumour is one that has spread to the other lung, the fluid around the lungs, lymph nodes, or other body structure or organs.

But, how do we describe the lung cancer stages if the patient has small cell lung cancer?

According to experts, we seldom use Stages 1 to 4 to discuss SCLC stages; usually, doctors only use these two:

• Limited Stage: This stage denotes a tumour that only affects one part of the chest. One in three people with small cell lung cancer is under the limited stage upon diagnosis.
• Extensive Stage: Extensive stage is somewhat similar to lung cancer stage 4. This means cancer has spread to other parts of the body. Many doctors also consider cancer that has spread to the fluid around the lungs as extensive. Two of three people with SCLC are usually under this stage upon their diagnosis.

Lung Cancer Treatment

The treatment strategies depend on several factors, including the lung cancer symptoms, type, stage, and of course, the individual’s health and tolerance to certain procedures and medications.

According to the Singapore Cancer Society, the three primary methods of lung cancer treatment are surgery, radiation therapy, and chemotherapy. But of course, there are other options, like targeted therapies and immunotherapy.

Here’s a quick guide on lung cancer treatment in Singapore:

Treatment For Non-Small Cell Lung Cancer

• Stages 1 and 2: If the patient is well enough, the doctor may advise surgery. To reduce the risk of recurrence, they might also recommend radiotherapy or chemotherapy after the operation.
• Stage 3: The physician may order radiotherapy with or without chemotherapy. After radiation, the patient might also undergo immunotherapy, where he or she receives medications that stimulate the immune system to kill the cancer cells.
• Stage 4: For stage 4 lung cancer, a huge part of treatment focuses on palliative care or in making sure that the patient is comfortable and not in pain. In this stage, the doctor may recommend a combination of chemotherapy, radiation, immunotherapy, and targeted therapy which involve medicines that slow down cancer spread.

Treatment For Small Cell Lung Cancer

If the individual is diagnosed with small cell lung cancer, the doctor may immediately recommend chemotherapy. This is because SCLC typically spreads quickly.

Should the physician note that the cancer is still localised, he or she may recommend a combination of radiotherapy and chemotherapy.

If SCLC is in the extensive stage, the patient may need a combination of chemotherapy and immunotherapy.

Lung Cancer Survival Rate

The lung cancer survival rate varies from person to person. But, over the years, experts have gathered enough data to identify the percentage of patients who survived a particular type and stage of lung cancer at a given time.

• The 5-year survival rate for lung cancer is 18.6%; this is lower than the survival rate for colorectal cancer (64.5%) prostate cancer (98.2%), and breast cancer (89.6%).
• When detected at an early, localised stage, the survival rate of lung cancer is 56%. However, only 16% of lung cancer cases are diagnosed early. Stage 4 lung cancer that has spread to other organs only has a 5-year survival rate of 5%.
• More than half of patients diagnosed with lung cancer die within a year of receiving their diagnosis.

Please note that the statistics above are merely based on observations and studies, and should not be used to predict whether a person will survive lung cancer or not.

Lung Cancer Prevention

As with any other type of cancer, there is no one sure way to prevent lung cancer. However, you can practise the following measures to reduce your risk:

• Stop or avoid smoking. Since 90% of lung cancer cases happen due to smoking, it is a good idea to avoid cigarettes as much as possible. Reducing your exposure to second-hand smoke also helps.
• Avoid or limit exposure to harmful chemicals and carcinogens. If your work involves exposure to carcinogenic substances, be strict in following safety protocols like wearing the right protective equipment.
• Have a healthy diet and regular exercise. No food can prevent cancer, but some might be able to reduce your risk. Good nutrition keeps your body strong and healthy. Similarly, exercise helps to strengthen your immune system.

Remember: If you suspect that you are experiencing signs of lung cancer, consult a doctor as soon as possible. 

Lung Cancer Support Groups in Singapore

In case you or your loved one is diagnosed with lung cancer, know that there are several support groups you can get in touch with, including:

Singapore Cancer Society Multi-Service Center

• Address: 9 Bishan Place #06-05, Junction 8 Office Tower, Singapore 579837
• Tel: 6499 9133

Singapore Cancer Society Rehabilitation Centre

• Address: 52 Jurong Gateway Road #08-04, JEM Office Tower, Singapore 608550
• Tel: 6661 0590

Note: The Singapore Cancer Society has a specific program for lung cancer patients. Meetings are held every 3rd Thursday of the month from 3:30 PM to 5:30 PM at the Singapore Cancer Society Rehabilitation Centre.

If you wish to receive expert and personalised care without leaving the comfort of your home, consider engaging Homage’s cancer care services. We will match you with a trained healthcare professional who can attend to your needs as necessary or round-the-clock, depending on your needs and preferences.