Lung Cancer

Currently, cancer is a major public health issue of the population worldwide, including Thailand.  According to the statistics of the World Health Organization (WHO) in 2018, approximately 18 million new cases are expected to be diagnosed and about 9.7 million are expected to die of cancer or accounted for 1 in 6 deaths due to cancer.

The overall situation of cancer in Thailand:  Based on the statistics, cancer is a number one cause of death, accounted for 16 % of all causes of death, which is 2 to 3 times higher than the accident-related mortality rate and heart disease, or an average of 8 case cancer death per hour.  In 2018, there were around 170, 495 new cancer cases and about 114,199 deaths due to cancer.  The top 5 most common cancer types include lung cancer, hepatocellular carcinoma and cholangiocarcinoma, breast cancer, colon and rectal cancer, and gallbladder cancer.  The first 5 leading causes of death from cancer include hepatocellular carcinoma and cholangiocarcinoma, lung cancer, gallbladder cancer, breast cancer and colon and rectal cancer, respectively.

Nowadays, there are no effective ways to prevent cancers.  In countries with low GDP per capital, such as Southeast Asian countries, an access to the preventive methods, diagnosis, and medical care for end-stage cancer is a major issue for both patients and countries.  More than 50 % of new cases of cancer is often diagnosed at stage 3 and 4, resulting in a high chance of death due to cancer when compared to the western countries.  The control and decrease in cancer-related mortality rate is substantially challenging problem.  An integrated plan and cooperation from all sectors, academic, government and people, are therefore needed in order to succeed.

1. Stop smoking or avoid being around smokers because cigarette smoking is the main cause of 80-90 % lung cancer.  Cigarette smoking induces bronchus cellular changes leading to cell mutations to cancer cells. 

2. Avoid highly-polluted areas, e.g. workplace with excess dust and smoke or in the mines without using protective gears; exposure to asbestos which is used in an automobile industry, insulation, construction, infrastructure, auto brake pads, clutch, and textile industry.  Also, avoid being exposed to 2.5 PM dust particles by wearing a mask when being outside.  Exposure to PM2.5 dust particles can also potentially increase a risk of cancer even if there is no academic evidence. 

3. Live in clean air areas

4. Regular check-up

5. Exercise regularly and eat a healthy diet to keep yourself healthy

6. Exposure to chest radiation and radon, which is colorless, odorless, radioactive gas.  It forms naturally from the decay of uranium in asbestos, which are found in the air and underground water and places with poor ventilation.  High level of radon exposure could increase a risk of lung cancer.

7. Those with lung disease-related scar e.g. tuberculosis or those with bronchitis are at higher risk of lung cancer development than normal people

8. Other factors, e.g. older age, use of certain narcotics, like marijuana and cocaine, vitamin A deficiency, may also involve lung cancer.  The relationship between genetics and lung cancer development is not established.

1. Respiratory tract symptoms include:
   - Persistent cough with or without phlegm
   - Cough that produces blood
   - Shortness of breath, breathing difficulty due to enlarged tumors, decreasing the ability to breath, or tumors blocking bronchial walls
   - Chest pain when breathing
   - Pneumonia, fever
   However, these symptoms are more likely to be caused by other lung diseases.  They may not always be the symptoms of lung cancer.

2. Other systemic symptoms include:
   - Loss of appetite, unexplained weight loss
   - Swelling in the face, arm, throat and upper body due to blood accumulation
   - Hoarseness due to cancer spreading to laryngeal nerves
   - Bone pain
   - Difficulty swallowing due to tumors blocking the esophagus
   - Paralysis due to brain or spinal cord metastases
   - Lumps on the skin

These symptoms are not specific to lung cancer.  Those with above symptoms should see a doctor. 

Lung cancer can be found by chest-x ray and CT scan.  The confirmatory diagnosis is to perform lung biopsy.  Most biopsy procedure is performed by bronchoscopy to collect lung tissues or punch biopsy by using CT scanner.

1. Biopsy

2. Fine-needle aspiration

3. Bronchoscopy

4. Thoracentesis

5. Mediastinoscopy

6. Thorocoscopy

7. Computed tomography (CT) scan and Magnetic Resonance Imaging (MRI): procedures to help a doctor to pinpoint the location and size of malignant tumors in the lungs

8. Positron emission tomography scan (PET scan): It is an injection with a glucose solution that contains a very small amount of radioactive material into a vein.  The substance is instantly absorbed by cancer cells more than normal cells, making distinctive cancerous cells only.

1. Non-small cell lung cancer has better prognosis than small cell lung cancer.  Early stage lung cancer patients are likely to be cured and have higher overall survival rate than later stage or metastasis lung cancer patients.

2. General health of the patients:  Patients without severe underlying diseases; patients without excessive weight loss often have better treatment outcome than unhealthy patients.

3. The right treatment chosen at an early stage is also important in the prognosis factor.  Generally, a doctor can improve patients’ well-being even if the disease cannot be cured. 

1. Small cell lung cancer
   Around 10-25 % of all lung cancers are this type. It is often found in bronchus more than peripheral lesion.  This cancer tends to grow and spread quickly and may produce certain substances, causing endocrine (hormone) system to function abnormally.  It tends to respond well to chemotherapy and radiation therapy

2. Non-small cell lung cancer
   Around 75-90 % of all lung cancers are this type.  Its progression is slower.  It is often diagnosed at earlier stage than small cell lung cancer.  If found at early stage, the main treatment is the resection of malignant tumors and lymph nodes.  Some may be treated with chemotherapy or radiation therapy.

1. Surgery is used to treat cancer at the early stage without spreading and the size of the tumors are not so large.  Cancerous tumors may spread to nearby lymph nodes and do not attached to important organs because this is an option to cure the disease.

2. Radiology is a local treatment, similar to surgery, and is suitable for:
   a. Early stage patients who cannot undergo surgery
   b. Locally advanced lung cancer patients, in combination with chemotherapy with radical aim
   c. Adjuvant therapy in stage 3 patients with indication to enhance the maintenance treatment
   d. Supportive care, lessening bone pain, lessening the symptoms in case of brain metastasis
   e. Prophylactic treatment e.g. brain radiotherapy to prevent cancer spreading to brain.

3. Chemotherapy is the administration of drugs to kill cancer cells through intravenous injection or infusion.  The drugs enter the bloodstream and can reach cancer cells throughout the body.

4. Targeted therapy is a type of cancer treatment with the aim to inhibit proteins which are important part to control cancer mechanism.  It is taken orally.  It has fewer side effects and effective in patients responding to the treatment.  It is often used as a second-line treatment when chemotherapy fails.

5. Immunotherapy is a mixture of drug substance and solution and given by intravenous infusion.  It is targeting to boost and restore the body’s immune system to function properly.  It has fewer side effects than chemotherapy and is often used as a second-line treatment when chemotherapy fails.

It is important to know choosing treatments may vary from person to person because even if the patients have the same type of cancer, the characteristics of mutations of cancer cells may differ. 

Therefore, the identification of the patients’ cancer cell mutations by Comprehensive Genomic Profiling will allow both doctors and patients to plan the proper treatment and ultimately choose the right medicines for patients.  

Reference

1. ทำความรู้จักกับมะเร็งปอด (Lung Cancer), โรงพยาบาลศิริราชปิยมหาราชการุณย์ http://www.siphhospital.com/th/news/article/share/621/Lungcancer

2. มะเร็งปอด,

3. มะเร็ง สาเหตุการตายอันดับ 1 ของคนไทยมากว่า 20 ปี,

4. คณะแพทยศาสตร์ 4 สถาบันเสนอนโยบายสู้มะเร็งที่ถูกต้องลดการเสียชีวิต,

5. อัตราการตายโรคมะเร็งปอด,

6. 5 วิธีการรักษามะเร็ง, http://www.siphhospital.com/th/news/article/share/231

7. Heim D et al. Int J Cancer 2014; 135: 2362–2369

8. Baumgart M et al. Am J Hematol Oncol 2015: 11: 10–13

9. Schwaederle M, Kurzrock R. Oncoscience 2015; 2: 779–780.

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