Lung cancer is cancer that begins in the lung. Cancer is a group of diseases characterized by abnormal cell growth with the potential to spread to other parts of your body. According to the American Cancer Society:
- Lung cancer is the second most common cancer in both men and women following skin cancer.
- About 13% of all new cancers are lung cancers.
- Lung carcinoma is the leading cause of cancer death in both men and women yearly.
- The majority of people diagnosed with lung cancer are 65 or older.
- The chance a man will develop cancer in his lifetime is about 1 in 15.
- The risk of a woman developing lung cancer is 1 in 17.
- Black people are at higher risk of developing and dying from lung cancer than other racial and ethnic groups.
What are the symptoms of Lung Cancer?
Lung cancer usually doesn’t cause signs and symptoms until it has spread. However, some people show symptoms in its earliest stages. The most common symptoms of lung cancer include:
- A cough that does not go away or worsens
- Coughing up blood or rust-colored sputum
- Chest pain that gets worse whenever you breathe deeply, laugh, or cough
- Shortness of breath
- Unexplained weight loss and loss of appetite
- Weakness and fatigue
- Lingering or recurrent respiratory infections such as bronchitis and pneumonia
If lung cancer spreads to other parts of the body (metastasizes), it may cause additional symptoms such as:
- Bone pain, especially in the back, hips, or ribs due to cancer spread to the bones.
- Headache, dizziness, balance problems, seizures, or numbness of limbs resulting from cancer spread to the brain or spinal cord.
- Lumps close to the surface of the skin due to cancer spread to the skin or lymph nodes, such as in the neck or above the clavicle (collarbone).
- Yellowing of the skin and eyes (jaundice) from cancer spread to the liver.
Additionally, some lung cancers cause syndromes. A syndrome is a group of signs and symptoms that occur together and characterize a particular abnormality or disorder.
Pancoast tumors, lung cancer situated at the top end (apex) of the lungs, can disrupt or damage nerves to the eye and part of the face, causing a group of symptoms known as Horner syndrome. These symptoms include:
- Drooping of one eyelid
- A small pupil in the same eye
- Little or no sweating on the affected side of the face
Pancoast tumors can also cause pressure on nerves in the upper chest, neck, face, and arms leading to:
- Severe shoulder pain
- Severe pain in the arm, hand, elbow, or armpit
- Hand weakness
- Tingling in the hands and fingers
- Atrophy (wasting away) of the hand and arm muscles
Superior vena cava syndrome (SVC)
SVC syndrome is a group of symptoms caused by the obstruction of the superior vena cava. The superior vena cava is a large vein that carries deoxygenated blood from the head, neck, upper chest, and arms to the heart.
It passes near the upper part of the right lung and the lymph nodes in the chest cavity. Tumors in or around these areas can press on the SVC, blocking the flow of blood, which can lead to:
- Swelling of the face, neck, upper chest, and arms
- Headaches, dizziness, and fainting if the brain is affected
SVC syndrome can develop gradually, but it can also quickly become life-threatening, requiring immediate medical attention.
Some lung cancers can make hormone-like substances that enter the bloodstream, affecting distant tissues and organs, even though the cancer has not spread to those organs or tissues.
The result being paraneoplastic syndromes, which can be the first symptoms of lung carcinoma. Common paraneoplastic syndromes associated with lung cancer include:
- SIADH (syndrome of inappropriate antidiuretic hormone): the cancer cells make the antidiuretic hormone (ADH), which causes the kidney to retain water. This upsets the body’s electrolyte balance creating symptoms such as fatigue, nausea & vomiting, headache, confusion, cramping or muscle weakness, and irritability. Severe cases can also lead to seizures and coma.
- Cushing syndrome: the cancer cells make the adrenocorticotropic hormone (ACTH), a hormone that stimulates the production of cortisol. Exposure to high levels of cortisol in a long time causes Cushing syndrome whose symptoms include weight gain, a fatty hump between the shoulder blades, easy bruising, round face, muscle weakness, and high blood pressure.
- Nervous system problems: lung carcinoma can cause the body’s immune system to attack healthy cells, tissues, and organs. This causes problems such as Lambert-Eaton myasthenic syndrome, an autoimmune disorder of the neuromuscular junction. LEMS symptoms include weakness of the muscles of the hips and thighs, which leads to difficulty in walking. The muscles of the shoulder and extraocular muscles may also become weak.
- High blood calcium levels (hypercalcemia): the condition can cause belly and bone pain, frequent urination, loss of appetite, thirst, constipation, fatigue, nausea, muscle weakness, and mental confusion.
- Exaggerated growth of certain bones, which can be painful.
- Blood clots.
- Excess breast growth in men (gynecomastia).
Most of these symptoms are likely to be caused by something other than lung cancer. However, if you experience any of these symptoms, it’s advisable to see your doctor straight away.
Lung cancer causes
Various factors can increase your risk of getting lung cancer. Some risk factors, such as smoking, can be changed. But others, such as your family history, are unchangeable.
Additionally, having a risk factor, or more, does not mean you will get the disease. Risk factors for lung cancer include:
- Smoking: according to the American Cancer Society, 80% of lung cancer deaths are thought to result from smoking. Your risk for lung cancer increases with the number of cigarettes you smoke in a day and how often you smoke.
- Passive smoking: exposure to secondhand smoke or environmental tobacco smoke can increase your risk of developing lung cancer. Secondhand smoke is thought to cause more than 7,000 deaths from lung cancer each year.
- Exposure to radon gas: radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rocks, and water. It is the second leading cause of lung cancer, and the leading cause among non-smokers in America according to the Environmental Protection Agency (EPA). There are usually higher levels of radon indoors (homes and other buildings) than outdoors.
- Exposure to asbestos and other carcinogens (cancer-causing agents): Working with asbestos and other carcinogens such as uranium, arsenic, coal products, and nickel compounds increase lung cancer risk, especially for smokers.
- Personal history of lung cancer: If you have had lung cancer, you have a higher risk of developing another lung cancer.
- Family history of lung cancer: Siblings and children of people who have had lung cancer have an increased risk of getting the disease.
- Air pollution: air pollution in cities, especially near heavily trafficked roads, slightly increases the risk of lung cancer.
Lung cancer types
There are different types of lung cancer, and the treatment options vary with each.
Non-small cell lung cancer
Non-small cell lung cancer is the most common lung cancer. About 85% of lung cancers are non-small cell cancers (NSCLC). Subtypes include:
- Squamous cell carcinoma, which begins in cells that line the passages of the respiratory tract.
- Adenocarcinoma, which forms in the outer part of the lungs.
- Large-cell carcinoma, which is fast-growing.
Small cell lung cancer
Small cell lung cancer, also known as oat cell cancer, represents 10% to 15% of lung cancers. It tends to spread quickly, making it more likely to respond to chemotherapy.
Lung carcinoid tumor
Less than 5% of lung cancers are lung carcinoid tumors. Most of these tumors grow slowly and rarely spread.
Lung cancer diagnosis
If there’s a reason to think you might have lung cancer due to your symptoms and the results of a screening test, your doctor will do various tests and exams to confirm. And if your medical history and physical exam suggest you have lung carcinoma, more tests will be done. These tests may include:
Sputum cytology: Sputum you cough up is looked at under a microscope to determine if cancer cells are present.
Imaging tests: These include a chest X-ray to check for anything suspicious. A computed tomography (CT) scan to show nodules and tell their size, shape, and position. And a positron emission tomography (PET) scan to reveal if a nodule is cancerous.
Biopsy: Involves getting a tissue sample and checking it for cancer cells.
A biopsy can be done in various ways, including:
- Bronchoscopy: a long, thin tube (bronchoscope) is passed down your throat and into the airways of your lungs. A thin needle at the end of the bronchoscope is used to get a biopsy sample.
- Mediastinoscopy: An incision is made at the base of your neck then surgical tools are inserted to take tissue samples from lymph nodes.
- Needle biopsy: using X-ray and CT images, a needle is inserted through your chest wall and into the nodule to get a sample.
Tissue samples are then sent to a lab for analysis. If the result is positive for cancer, further testing, such as a bone scan, can help determine if the cancer has metastasized and to help with staging.
Stages of Lung cancer
Cancer stages tell how far cancer has spread and help determine the most appropriate treatment. Staging tests include CT, MRI, PET, and bone scans.
Non-small cell lung cancer stages range from:
Stage 0: The tumor is found only in the top layers of cells lining the air passages.
Stage I: Cancer is found in the lung, but it has not spread outside the lung.
Stage II: Cancer is found in the lung and nearby lymph nodes.
Stage III: Cancer is in the lung and lymph nodes in the middle of the chest.
Stage IV: Cancer has spread to both lungs, into the area around the lungs, or to distant organs.
Small-cell lung cancer (SCLC) has two main stages. In the limited stage, cancer is found in only one lung or nearby lymph nodes on the same side of the chest. While the extensive stage means cancer has spread:
- Throughout one lung
- To the opposite lung
- To lymph nodes on the opposite side
- To fluid around the lung
- To bone marrow
- To distant organs
Lung Cancer Treatment
Your doctor will help you choose an appropriate cancer treatment plan based on your overall health, the type, and stage of lung cancer, your preferences, among other factors. Treatment options for lung cancer include:
Surgery: you may opt for surgery to remove part or the whole of your lung. If you’re at high risk of recurrence, chemotherapy or radiation therapy may be recommended after surgery.
Radiation therapy: uses high-powered energy beams to kill cancer cells. It may be used before or after surgery in people with locally advanced cancer. Radiation therapy can also be used to relieve pain and other symptoms in patients with advanced lung cancer. It is often combined with chemotherapy.
Chemotherapy: uses drugs to kill cancer cells. Drugs can be taken intravenously or orally. Chemotherapy is often used after surgery to kill any cancer cells that may have been left behind. It is also used before surgery to shrink cancers and make them easier to remove.
Targeted therapy: causes cancer cells to die by targeting and blocking specific abnormalities in cancer cells. It is mostly reserved for people with advanced or recurrent cancer.
Immunotherapy: uses the immune system to fight cancer. The treatment is generally reserved for people with advanced lung cancer.
Palliative care: involves minimizing your signs and symptoms and ensuring your comfort during and after treatment. Palliative care is also known as supportive care.
Lung cancer prevention
To reduce your risk of lung cancer:
- Don’t start smoking
- Quit smoking
- Avoid secondhand smoke
- Test your home for radon
- Protect yourself from exposure to carcinogens at work by wearing protective gear
- Eat a healthy diet full of fruits and vegetables
- Exercise regularly
Smoking and lung cancer
Smoking is the biggest risk factor for lung cancer, causing 9/10 lung carcinomas. Doctors believe smoking causes lung cancer by damaging the cells that line the lungs.
According to the Centers for Disease Control and Prevention (CDC), cigarette smokers are 15 to 30 times more likely to get lung cancer than nonsmokers.
Breathing in secondhand smoke is also a major factor, with over 7300 non-smokers dying each year in the US from lung cancer caused by secondhand smoke.
Tobacco products contain over 7000 chemicals, and at least 70 are known to cause cancer. When you inhale cigarette smoke, these carcinogens are directly delivered to your lungs, where they immediately begin causing damage to the lung tissue.
Your body is able to repair the damage at first, but repeated exposure becomes increasingly harder to manage. Over time, the damage causes cells to mutate and grow out of control.
When you smoke, the cancer-causing substances also enter your bloodstream and are carried throughout your body, increasing the risk of other types of cancer.
People who quit smoking reduce their risk of lung cancer considerably. Within 10 years of quitting, the risk of dying from lung cancer drops by half.
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