สาเหตุ อาการ วิธีการรักษา และวิธีป้องกันโรคมะเร็งปอด - Lung Cancer – Causes, Symptoms, Treatments, and Preventions

Lung Cancer

Lung cancer is a disease caused by uncontrolled cell division in the lungs. The damaged cells irregularly divided or excessively imitated themselves (mutations) to form masses or tumors of tissue.

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Lung cancer

Lung cancer is the leading cause of cancer deaths for Thais and the global population. It is a genuine silent threat, as it grows and spreads surreptitiously without disclosing any warning sign. The patient becomes aware of the symptoms only when the lung cancer has progressed to the late, extensive stage. Even though people are knowledgeable about cancer risk factors, very few can detect them at the early stages.

What causes lung cancer?

Lung cancer is caused by the uncontrolled proliferation of mutated cells in the lung, forming a mass or nodule that affects or interrupts the normal function of the lung. It typically begins as a tiny spot, often in the airways or air sacs of the lung, and quickly spreads to adjacent organs.

How many types of lung cancer?

Lung cancers are classifiable into two major types based on their characteristics.

  1. Small cell lung cancer(SCLC)
    Small-cell lung cancer (SCLC) is a type of lung cancer that grows and spreads faster than non-small cell lung cancer (NCLC). It is common in long-term heavy smokers, people chronically exposed to second-hand smoke, soot, or dust containing PM2.5.
  1. Non-small cell lung cancer(NSCLC)
    Non-small-cell lung cancer (NSCLC) is the most common type of cancer (85-90% of lung cancer patients). Typically, non-small-cell lung cancer is a type of cancer that grows and spreads slower than small-cell lung cancer (SCLC). Non-small-cell lung cancer can be entirely cured by medical treatment if detected and appropriately treated early.
    Non-small-cell lung cancer (NSCLC) is the predominant type, 85-90% of lung cancers. It has a slower growth and spread than small-cell lung cancer (SCLC) and can be cured by medical treatment only if detected and appropriately treated early.

 

What are the stages of lung cancer?

The staging of lung cancer varies depending on its type. Criteria to determine the cancer stage depend on the cancer size, location, and the spread of cancer to distant sites and body organs. Therefore, knowing a patient’s cancer stage is crucial for the cancer doctor to formulate the most suitable treatment plan for an individual patient.

There are 2 stages of small-cell lung cancer.

  • Limited Stage: Cancer is in just one lung and possibly a nearby lymph node.
  • Extensive Stage: Cancer has spread to other areas of the lung, chest, fluid around the lungs, and other organs such as the brain.

There are 4 stages of non-small cell lung cancer.

  • Stage I: Cancer forming on the upper lung or in a bronchus, increasing in size but not spreading outside the lung or to lymph nodes. At this stage, there is no sign or symptom present.
  • Stage II: Cancer has spread to the lymph nodes inside the lungs. One or more tumors may form in the same lobe of the lung. Surgical tumor removal alone can treat patients at this stage.
  • Stage III: Cancer has bigger sizes than stage II. One or more tumors have formed and spread to other lobes of the same lung, lymph nodes, or the middle of the chest structures. 
  • Stage IV: Cancer has spread to other body organs; the other lung, the fluid around the heart, or the lymph nodes in the neck, liver, bones, adrenal glands, and brain.

There are 4 stages of non-small cell lung cancer

What are the symptoms of lung cancer?

Lung cancer at an early stage does not have any signs or symptoms. However, symptoms such as cough or fatigue can be a daily occurrence. As a result, many patients delay initial screening until the cancer has progressed to an advanced stage.

Signs and symptoms of lung cancer include:

  • Chronic cough
  • Coughing up blood (hemoptysis)
  • Shortness of breath (dyspnea)
  • Wheezing, Hoarseness
  • Headache
  • Fatigue, Tiredness
  • Chest or upper chest pain
  • Loss of appetite
  • Unexplained weight loss
  • Shoulder pain
  • Bone pain
  • Swelling in the face, neck, and arms 


Risk factors of lung cancer include:

Factors that may influence the risk of lung cancer are classifiable into controllable factors; smoking, and uncontrollable factors; genetics. In addition, being health-conscious and practicing prevention can lower the risks.

Smoking

Cigarette smoking is always topmost on the list of risk factors for lung cancer. Experts estimate that over 80% of lung cancer deaths are smoking-related. Therefore, smokers are more likely to develop or eventually die from lung cancer than non-smokers. Even smoking a few cigarettes a day or casual smoking can increase the risk of lung cancer. Cigarette smoking can cause cancer in every organ. Stopping smoking can lower the risk of lung cancer.

Risk factors of lung cancer.

Second-hand smoke

Second-hand smoke exposure has become one of the leading causes of lung cancer. Second-hand smoke is the exhaled smoke of the firsthand smoker. Inhaling second-hand smoke, even for a short period, can cause serious health issues, particularly for babies, children, and family members around smokers. In addition, exposure to second-hand smoke adversely affects the cardiovascular system, including the heart, blood, and blood vessels, leading to heart disease, stroke, etc.

Previous radiation therapy

Individuals with a history of radiation treatment to the chest, breast, or for lymphoma, etc., have an increased risk of lung cancer

Exposure to radon gas, asbestos, and other carcinogens

Radon gas, asbestos, and other carcinogens such as uranium, diesel exhaust, or coal products are harmful substances that diffuse, forming air pollution. Breathing such substances over time can increase the risk of lung cancer. In addition, radon gas, asbestos, and other carcinogens can adhere to the building's interior infrastructure. However, we can control these substances by installing an air-filtration system in the living facility.

Family cancer syndrome or hereditary cancer syndrome

Individuals with family cancer syndrome have a higher risk of lung cancer than a person without the syndrome. The syndromes are due to inherited genetic variants in specific cancer-related genes. Experts estimate that over 80% of lung cancer deaths in individuals with family cancer syndrome are smoking-related.

Diagnosis of lung cancer

  • Lung cancer screening
    People with a high risk of lung cancer, especially current cigarette smokers or adults who smoked heavily for many years, should undergo low-dose lung CT scans annually. Patients should consult their doctors for more information.

Investigations to diagnose lung cancers

Many investigative approaches are available, including:

  • Imaging testsA low-dose lung CT scan can reveal abnormal tumors or nodules in your lungs that may not be detectable on a conventional chest X-ray.
  • Sputum cytology: Sputum examination under the microscope can sometimes reveal cancer cells from the lung.
  • Biopsy: To obtain tissue samples for pathologic examinations in several ways, such as CT-guided needle aspiration of suspicious lung nodules. 
  • Bronchoscopy: A lighted, flexible scope is inserted through your neck into your lungs to examine for areas with abnormalities.
  • Mediastinoscopy:  A rigid scope is inserted behind your breastbone through the base of the neck incision to take tissue samples.

It is also possible to take tissue biopsy from a metastatic cancer site such as the liver. Correct diagnosis of the type of lung cancer will be crucial in the treatment options.

Diagnosis of lung cancer

Lung cancer treatments

The treatment plan depends on several criteria, including your general health, the type and stage of your cancer, and your personal preferences.

  • Surgery: focuses on removing the cancerous tumors in the lung and the central chest lymph nodes for further examination. Surgery is an option for cancer confined to the lung. In some cases, the doctors may administer chemotherapy or radiation to kill and shrink the cancer cells before surgery.
  • Radiation therapy uses high-energy or proton beams to kill cancer cells and shrink tumors, often combined with chemotherapy before or after surgery. Radiation therapy may be the primary treatment option for advanced lung cancer patients.
  • Chemotherapy: Chemotherapy uses medications to kill cancer cells over weeks or months. Chemotherapy medications may be taken orally, or given through the veins in your arms, sometimes to kill remaining cancer cells and relieve pain caused by cancer.
  • Targeted therapy: Targeted drug therapy focuses on finding specific cellular pathways driving the growth of cancer cells and blocking them, causing these cancer cells to stop growing. A cancer gene mutation is studied and tested. This approach applies to patients with advanced cancer.
  • Immunotherapy: Immunotherapy harnesses your immune system to seek out and kill cancer cells. This treatment is suitable for patients with cancers spreading to other body sites.
  • Palliative care and pain management: This is also known as supportive care. This approach places the patients in a healthy and resilient psychological state after being diagnosed with cancer and undergoing treatment. Research indicated that, on average, patients with advanced non-small cell lung cancer who received palliative care lived almost three months longer than those who received standard treatment.

Self-care at home for lung cancer patients

  • Breathing Control: Suffering from suffocation is a distressing sensation that can lead to anxiety. Through breath meditation, patients can feel more relaxed by focusing on the muscles that control their breathing. In addition, leaning forward can also help you breathe more easily. People who have difficulty breathing can easily become tired, so save your energy for what is truly necessary.


How can I prevent lung cancer?

You can reduce the risk of lung cancer by taking these preventive measures or eliminating the causes:

  • Stop Cigarette Smoking
    Do not pick up a smoking habit or quit if you are a smoker. When you stop smoking, you decrease not only your risk but also the risk of lung cancer for the people around you. In addition, as soon as you stop smoking, your damaged lung tissue starts to repair itself and helps increase the chance of living a long healthy life.
    If you plan to stop smoking but find it difficult to quit, you should consult a doctor. They will find you a plan or stop-smoking aids to help you quit, such as nicotine replacement products, medications, or a helpful, informative consultation.
  • Avoid second-hand smoke.
    Second-hand smoke causes cancer even in non-smokers. If second-hand smoke is unavoidable, wear protective face masks to filter exhaled toxic smoke. In addition, staying away from smoking areas where smoke is most dense can minimize the risk of inhaling toxic substances.
  • Eat healthy foods.
    Healthy foods, particularly vegetables and fruits, are enriched with essential substances, including antioxidants, vitamins, and minerals, to boost your immune system in defense and protection against free radicals—one of the causes of cancer.
  • Exercise regularly.
    Exercise is the best medicine. Regular exercise reduces the risk of cancer, enhances overall function, improves brain health, manages chronic health conditions and disabilities, improves the ability to do activities and prevent falls, strengthens bones and muscles, and increases the chance of living longer.


Is PM2.5 related to lung cancer?

Recently, scientists at the Francis Crick Institute and University College London presented their findings at the ESMO congress 2022 regarding the cancer-causing mechanism of the pollutant PM2.5 particles. A healthy individual may already harbor a copy of the mutated EGFR gene, which seems to increase with age. PM2.5 promoted mutation in the remaining normal EGFR gene leading to the cancerous transformation of the lung cells.

PM2.5 can trigger lung cancer, particularly among chronic smokers. However, studies also found a strong correlation between PM2.5 exposure and lung cancer in people without a smoking history.

Annual lung cancer screening and check-up

According to the National Cancer Institute (Thailand), lung cancer is on the list of the top five cancers in Thailand and worldwide. The number of patients diagnosed with lung cancer is increasing each year. Early detection is the key to saving a life. You should have an annual lung cancer screening if you meet one or more of the following criteria:

  • You have a history of smoking or have been smoking for many years.
  • You chronically inhale second-hand smoke.
  • You are exposed to air pollution, chemicals, radon, and PM2.5.
  • You are between 50-80 years old.
  • You have a family history of hereditary cancer syndrome.

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มะเร็งปอด Lung cancer - infographic

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Published: 30 Jan 2023

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