Lung cancer is the primary cause of cancer deaths around the world, and it is common for both men and women. Like all other cancers, lung cancer is also caused by a mutation in the cell’s DNA leading to an uncontrolled growth of abnormal cells in one or both the lungs. As the number of abnormal cells grows, they form tumours and interfere with the normal functioning of the lung and hinder its work of supplying oxygen to the body through blood. If diagnosed and treated at an early stage, almost half of the lung cancer patients can stay alive and eventually recover from recurrent cancer 5 years later. The sad thing is that most lung tumours are malignant which means they invade and destroy the healthy tissues present around them and rapidly spread throughout the body. The lung is the worst place for a cancer to develop because it possesses a strong network of blood vessels and lymphatic channels which aid the cancer to spread readily.
Causes of Lung Cancer
The most common cause of lung cancer is smoking. But lung cancer can also develop in people who have never smoked in their lives.
Smoking - Smoking cigarettes, cigars, and pipe tobacco is one of the main causes of lung cancer and almost 85% of all the lung cancer cases are caused due to smoking. Tobacco smoke contains almost 60 different types of toxic, carcinogenic substances which lead to the development of cancer.
Passive Smoking - Even if you are not a smoker, yet frequent exposure to tobacco smoke can increase the risk of lung cancer.
Occupational Exposure to Carcinogenic Substances - Exposure to certain substances and chemicals used in several industries is linked to a higher risk of developing lung cancer. These toxic chemicals and substances include asbestos, arsenic, beryllium, cadmium, silica, coke and coal fumes.
Heredity - Other than smoking and exposure to toxic substances, the genetics also plays a determining role in the causation of cancer. Research shows that cancer is more likely to develop in people who have a history of lung cancer in their family.
Lung Diseases - Certain lung diseases such as chronic obstructive pulmonary disease (COPD) or tuberculosis is linked to an increased risk of development of lung cancer.
Types of Lung Cancer
There are 2 main types of lung cancer – Squamous Cell Carcinoma and Adenocarcinoma. Non-small cell lung cancer can be further segregated into 2 subtypes.
Squamous cell carcinoma - It is also known as epidermoid carcinoma, and it is the most common type of non-small cell lung cancer in men in which the cancer affects the linings of the bronchial tubes.
Adenocarcinoma - It is the most common type of lung cancer affecting women and non-smokers, and it forms in the mucus-producing glands of the lungs.
Bronchioalveolar carcinoma - This is a rare type of adenocarcinoma that forms near the air sacs of the lungs.
Large-cell undifferentiated carcinoma - This is a rapidly growing cancer that forms near the outer edges or surface of the lungs.
What are the Symptoms of Lung Cancer?
The symptoms of lung cancer take years to develop, or they may not appear till the disease is advanced. The lung cancer symptoms are often confused with bronchitis. Symptoms of lung cancer include:
- Intense and persistent coughing
- Chest pain, shoulder pain and back pain
- Change in color or volume of sputum
- Shortness of breath
- The voice becoming hoarse
- Sounds with each breath
- Recurrent lung problems like bronchitis or pneumonia
- Coughing up blood
- Presence of blood in phlegm or mucus
Treatment for Lung Cancer
Treatment of lung cancer depends on the types of lung cancer. There are 2 different types of treatment for non-small cell lung cancer and small cell lung cancer.
Treatment for Non-Small Cell Lung Cancer
The treatment for non-small cell lung cancer involves a combination of surgery, radiation, chemotherapy and targeted treatments.
Surgery - Surgery is the best method to treat non-small cell lung cancer in the primary stages. In this procedure, the surgeon removes the lobe or the portion of the lung containing the cancerous tumour. In most cases, the surgeon uses a video-assisted thoracoscope to see inside the chest and then remove the lung lobe with the help of the scope without making a large incision in the chest.
Chemotherapy and Radiation - Administering chemotherapy after surgery, also known as “adjuvant chemotherapy,” can help prevent the recurrence of the cancer. Chemotherapy is also recommended for people with stage 3 lung cancer in combination with high-dose radiation treatment. In stage 4 lung cancer chemotherapy is the main treatment and radiation is only used for palliation of symptoms.
Targeted Treatments - One of the ground-breaking discoveries in the field of lung cancer treatment is the introduction of targeted treatments that specifically attack only the cancer cells. People with advanced lung cancer can receive targeted treatment alone or in combination with chemotherapy. Targeted treatments for lung cancer include:
- Erlotinib - This drug blocks a specific kind of receptor on the cell surface known as the epidermal growth factor receptor (EGFR). This receptor encourages the growth and spread of cancer cells. Lung cancer cells that have an EGFR mutation are likely to respond to this drug.
- Bevacizumab - Just like normal cells the tumours also need blood supply to survive. A substance known as the vascular endothelial growth factor (VEGF) stimulates the blood vessels to penetrate the tumour and supply oxygen and nutrients to the tumour. Bevacizumab functions by stopping the VEGF from encouraging the growth of new blood vessels. When combined with chemotherapy, this drug can enhance the chances of survival of people with adenocarcinoma and large cell carcinoma of the lung.
- Crizotinib - This treatment shows benefits for people with advanced non–small cell lung cancer who have the ALK biomarker. Crizotinib works by blocking the ALK and preventing the growth of the tumour.
Treatment for Small Cell Lung Cancer
- Chemotherapy is an essential part of treatment for people with small cell lung cancer.
- Radiation treatment may be used in combination with chemotherapy depending on the stage of the cancer.
- People with limited-stage small cell cancer are administered a combination of chemotherapy and radiation therapy.
- The most commonly used chemotherapy medicines include etoposide, plus cisplatin.
- In case of small cell lung cancer, the cancer can spread to the brain and therefore, doctors may prescribe radiation therapy to the brain.
- A small percentage of people with limited-stage small cell lung cancer and no lymph node tumours can benefit from surgery.
There is no sure-fire way to prevent lung cancer, but you can take some precautions to reduce the risk of developing lung cancer. Some of the preventive measures include giving up smoking, avoiding exposure to carcinogens at work and eating a diet containing antioxidant-rich fruits and vegetables.
All the treatments – medicines, injections and vaccines are for general information of the reader. Please consult a doctor and get a formal prescription before taking any medicines, supplements and injections.
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