Causes and Treatments of Lung Cancers | Oncology

Lung cancers

What are lung cancers?

Lung cancer, like all types of cancer, results from a defect in the body’s basic unit of life, the cell. Normally, the body maintains a system of checks and balances over cell growth so that cells divide to produce new cells only when new cells are needed.

Disruption of this system of checking and balancing on cell growth makes results in uncontrolled cell division and proliferation that eventually forms a mass known as a tumor.

Tumors can be benign or malignant; When we talk about “cancer”, we mean malignant tumors. Medical professionals can usually remove benign tumor cells/mass, and then these tumors do not spread to other parts of the body.

Malignant tumors, on the other hand, often grow aggressively locally where they start, but tumor cells can also enter the bloodstream or lymphatic system and then spread to other sites in the body. This process of spread is called metastasis; areas of tumor growth at these distant sites are called metastases.

Since lung cancer tends to spread or metastasize very soon after it forms, it is a very life-threatening cancer and one of the most difficult cancers to treat. While lung cancer can spread to any organ inside the human body, certain locations, particularly the adrenal glands, liver, brain, and bones, are the common sites for lung cancer metastasis in the human body.

The lung is also a very common site of malignant tumor metastasis in other parts of the body. The same types of cells as the original (primary) tumor form tumor metastases. For example, if prostate cancer spreads through the bloodstream to the lungs, it is metastatic prostate cancer in the lung and it is not lung cancers.

The main function of the lungs is to exchange gases between the air we breathe and the blood. Through the lung, carbon dioxide is removed from the body’s bloodstream and oxygen enters the bloodstream. The right lung has three lobes, while the left lung has two lobes and a small structure called a lingula that is the equivalent of the middle lobe on the right.

The main airways that enter the lungs are the bronchi, which arises from the trachea, which is located outside the lungs. The bronchi branch into progressively smaller airways called bronchioles that end in small sacs known as alveoli where gas exchange occurs. A thin layer of tissue called the pleura covers the lungs and chest wall.

Lung cancers can arise in any part of the lung, but between 90% and 95% of lung cancers arise from epithelial cells, the cells that line the largest and smallest airways (bronchi and bronchioles); for this reason, lung cancers are also known as bronchogenic cancers of bronchogenic carcinomas. (Carcinoma is another term for cancer). Cancers can also arise from the pleura (called mesotheliomas) or rarely from the supporting tissues within the lungs, for example, blood vessels.

Alternate name

Lung cancers, also known as lung carcinoma

Types of lung cancers

Non-small cell lung cancer (NSCLC)

About 80% to 85% of lung cancers are NSCLC which is a 1st type as declared previously. The major subtypes of NSCLC are adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. These subtypes, which are starting from different types of lung cells, are grouped as NSCLC because their treatment/cure and prognosis (outlook) are often similar.


Adenocarcinomas start in cells that would normally secrete substances like mucus. This type of lung cancer cases are occurring mainly in current or former smokers, but it’s also one of the most common types of lung cancers seen in non-smokers nowadays. It is more common in women than in men and is more likely to occur in younger people than other types of lung cancer.

Adenocarcinoma is usually found in the outer parts of the lung and is more likely to be detected before it has spread. People with a type of adenocarcinoma called adenocarcinoma in situ (formerly called bronchioloalveolar carcinoma) tend to have a better prognosis than those with other types of lung cancer.

Squamous cell carcinoma

Squamous cell carcinomas start in squamous cells, which are flat cells that line the inside of the airways of the lungs. They are often related to a history of smoking and tend to be found in the central part of the lungs, near the main airway (bronchi).

Large cell carcinoma (undifferentiated)

Large cell carcinoma can appear anywhere in the lung. It tends to grow and spread quickly, which can make it difficult to treat. A subtype of this large cell carcinoma is known as the large cell neuroendocrine carcinoma, which is fast-growing cancer that is very similar to small cell lung cancer.

Other subtypes

Some other subtypes of NSCLC, such as adenosquamous carcinoma and sarcomatoid carcinoma, are much less common.

Small Cell Lung Cancer (SCLC)

About 10% to 15% of all lung cancers are SCLC and it is often called oat cell cancer.

This lung cancer type tends to grow and spread faster than NSCLC. About 70% of people with SCLC will have cancer that has already spread by the time it is diagnosed. Since this cancer grows rapidly, it tends to respond well to chemotherapy and radiation therapy. Unfortunately, It has been seen for most people that cancer will return at some point.

What causes lung cancers?

Smoking causes most lung cancers, both in smokers and in people exposed to secondhand smoke. But lung cancer also occurs in people who never smoked and who never had long-term exposure to secondhand smoke. In these cases, there may not be a clear cause of lung cancer.

How smoking causes lung cancer:

Doctors believe that smoking causes lung cancer by damaging the cells that line the lungs. When you breathe in cigarette smoke, which is full of carcinogens (carcinogens), changes in lung tissue begin almost immediately.

At first, your body can repair this damage. But with each repeated exposure, the normal cells that line your lungs become more and more damaged. Over time, the damage makes causes cells to act abnormally, and eventually, cancer can develop.

Risk factors

Several factors can increase your risk of lung cancer. Some risk factors can be controlled, for example, by quitting smoking. And other factors can’t be controlled, like your family history.

Risk factors for lung cancer include:

  • Smoke: Your risk of lung cancer depends on increases in the number of cigarettes you smoke each day and the total number of years you have smoked. Quitting smoking at any age can significantly reduce your risk of developing lung cancer.
  • Exposure to secondhand smoke: Even if you don’t smoke, your risk of lung cancer increases if you are exposed to secondhand smoke.
  • Previous radiation therapy: If you have had radiation therapy to the chest for another type of cancer, you may have an increased risk of developing lung cancer.
  • Exposure to radon gas: Radon is produced by the natural breakdown of uranium in soil, rocks, and water, which eventually becomes part of the air you breathe. Dangerous levels of radon can build up in any building, including houses.
  • Exposure to asbestos and other carcinogens: Exposure in the workplace to asbestos and other substances that are known to cause cancer, such as arsenic, chromium, and nickel, can increase the percentage of your risk of developing lung cancer, especially if you are a smoker.
  • Family history of lung cancer: People with a parent, sibling, or child with lung cancer are at increased risk for the disease.

Lung cancers symptoms

In people with lung cancer, symptoms don’t always occur until the condition has reached a later stage. However, some people may notice symptoms often, which they may think are related to a little serious acute illness.

Examples of these symptoms include:

  • Loss of appetite
  • Changes in a person’s voice, such as hoarseness
  • Frequent chest infections in the body, such as bronchitis or pneumonia
  • A persistent cough that may start to get worse
  • Difficulty breathing
  • Unexplained headaches
  • Weightloss
  • Wheezing

A person can also experience more serious symptoms associated with lung cancer. These symptoms included severe chest or bone pain or coughing up blood.

Lung cancers diagnosis

After a physical exam, your doctor will tell you how to prepare for specific tests, such as:

  • Imaging tests: An abnormal mass can be seen on X-rays, MRIs, CT scans, and PET scans. These scans make help to produce more detail and find smaller lesions.
  • Sputum cytology: If you cough up phlegm, microscopic examination can determine if cancer cells are present.

A biopsy can determine if the tumor cells are cancerous. A tissue sample can be obtained by:

  • Bronchoscopy: While under sedation, a lighted tube is passed down the throat into the lungs, allowing for a more detailed examination.
  • Mediastinoscopy: The doctor cuts the base of the neck in the human body. A lighted instrument is inserted and surgical tools are used to sample the lymph nodes. It is usually done in a hospital under general anaesthesia.
  • Needle: Using imaging tests as a guide, a needle is inserted through the chest wall and into suspicious lung tissue. A needle biopsy can also be used to examine lymph nodes.

The tissue samples are sent to a pathologist for analysis. If the result is positive for cancer, additional tests, such as a bone scan, can help find out if cancer has spread and helped with staging.

For this test, you will be injected with a radioactive chemical. Abnormal areas of the bone will be highlighted in the images. MRI, CT, and PET are also used for staging.

Lung cancers treatment options

It is generally a good idea to seek a second opinion before starting treatment. Your doctor can help you make that happen. If you are diagnosed with lung cancers, your care will likely be managed by a team of doctors that may include:

  • A surgeon who has specialization in the chest and lungs (thoracic surgeon)
  • A lung specialist (pulmonologist)
  • A medical oncologist
  • A radiation oncologist

Review all of your treatment options before making a decision. Your doctors will coordinate care and keep each other informed. Treatment for non-small cell lung cancer (NSCLC) varies from person to person. Much depends on the specific details of your health.

  • Stage 1 NSCLC: Surgery to remove part of the lung may be all you need. Chemotherapy may also be recommended, especially if you have a high risk of recurrence.
  • Stage 2 NSCLC: You may need surgery to remove part or all of your lungs. Chemotherapy is generally recommended.
  • Stage 3 NSCLC:  At this stage, you may require a combination of chemotherapy, surgery, and radiation therapy.
  • Stage 4 NSCLC is particularly difficult to cure. Options include surgery, radiation, chemotherapy, targeted therapy, and immunotherapy.

Options for small cell lung cancer (NSCLC) also include surgery, chemotherapy, and radiation therapy. In most cases, cancer will become too advanced for surgery. Clinical trials provide access to promising new treatments. Tell your doctor if you are ready for a clinical trial.

Some people with advanced lung cancers choose not to continue treatment. You can choose palliative care treatments, which are mainly focused on treating the symptoms of cancer rather than cancer itself.


There is no sure way to prevent lung cancers, but you can lower your risk by:

  • Do not smoke: If you’ve never smoked, don’t start. Talk to your children about not smoking so they can understand how to avoid this important risk factor for lung cancer. Start conversations about the dangers of smoking with your kids early so they know how to react to peer pressure.
  • Stop smoking: Stop smoking now. Quitting smoking reduces your risk of lung cancer, even if you have smoked for years. Talk to your doctor about quit strategies and aids that can help you quit. Some options include nicotine replacement products, such as medications, and support groups.
  • Avoid secondhand smoke: If you live or work with a smoker, encourage them to quit. At the very least, ask him to smoke outside. Avoid areas where people smoke, like bars and restaurants, and look for smoke-free options.
  • Check your home for radon: Monitor radon levels in your home, especially if you live in an area where radon is known to be a problem. High radon levels can be remedied to make your home safer than others. For information on radon testing, contact your local public health department or a local chapter of the American Lung Association.
  • Avoid carcinogens at work: Take more precautions to protect yourself from exposure to toxic chemicals at work. Follow your employer’s precautions. For example, if you are given a mask to protect yourself, always wear it. Ask your doctor what else you can do to protect yourself at work. Your risk of lung damage from carcinogens in the workplace increases if you smoke.
  • Eat a healthy and rich diet in fruits and vegetables: Choose a good healthy diet with a variety of fruits and vegetables. Food sources of vitamins and nutrients are the best. Avoid taking large doses of vitamins in pill form, as they can be harmful. For example, researchers who hoped to reduce the risk of lung cancer in heavy smokers gave beta-carotene supplements. The results showed that the supplements actually increased the risk of cancer in smokers.
  • Exercise most days of the week: If you don’t exercise regularly, start slowly. Try to exercise most days of the week.


Lung cancers can cause complications, such as:

  • Difficulty breathing: People with lung cancers may experience shortness of breath if cancer grows and blocks the main airways. Lung cancer can also cause fluid to collect around the lungs, making it difficult for the affected lung to fully expand when inhaled.
  • Coughing up blood: Lung cancers can cause bleeding in the airways, which can cause you to cough up blood (hemoptysis). Sometimes the bleeding can become severe. Treatments are available to control bleeding.
  • Advanced lung cancers start spreads to the lining of a lung or to another area of ​​the body, such as inside a bone, which makes pain. Tell your doctor if you experience any type of pain, as there are many treatments available to control pain.
  • Fluid in the chest (pleural effusion): Lung cancers can cause fluid to build up in the space around the affected lung in the chest cavity (pleural space).

Fluid buildup in the chest can cause shortness of breath. Treatments are available to drain fluid from the chest and reduce the risk of recurrent pleural effusion.

  • Cancer starts to spread to other parts of the body (metastasis): Lung cancers often spread (metastasizes) to other parts of the body, such as the brain and bones.

Cancer that spreads can cause pain, nausea, headaches, or other signs and symptoms, depending on the organ affected. Once lung cancers have spread beyond the lungs, it is generally not curable. Treatments are available to decrease signs and symptoms and help you live longer.

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