Lung Cancer: Symptoms, Causes, Stages, Treatment and more

As the name suggests lung cancer is a type of cancer that starts in the lungs. When cells in the body start begin to grow out of control cancer starts.

A short description of the lungs before going into detail about lung cancer.

About Lungs

Lungs are 2 sponge-like organs present in the chest. The right side of the lung has three sections known as lobes and the left side has two lobes. Let us tell you that the left lung is smaller because of the heart as it takes up more room on that side of the body.

Structure and working of lungs

When we breathe in, air enters through the mouth or nose and goes into the lungs through trachea or windpipe. The trachea divides into tubes known as bronchi which enters the lungs and divide into smaller bronchi. They further divided to form smaller branches called bronchioles. Alveoli are the tiny air sacs present at the end of the bronchioles.

Now the alveoli absorb oxygen into your blood from the inhaled air and remove carbon dioxide from the blood at the time of exhaling. The main function of the lungs is to take in oxygen and getting rid of carbon dioxide. Basically, lung cancer starts in the cells lining the bronchi and parts of the lung like bronchioles or alveoli.

There is a thin lining of the layer that surrounds the lungs known as pleura. The function of pleura is to protect the lungs and helps them slide back and forth against the chest wall as they expand and contract during breathing.

The diaphragm is present below the lungs which are thin, dome-shaped muscles that separate the chest from the abdomen. While breathing, the diaphragm moves up and down, force air in and out of the lungs.

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Lung Cancer: types

Two main types of lung cancer are there:

1. Non-small cell lung cancer (NSCLC)

It is said that about 80 to 85% of lung cancers are NSCLC. The main subtypes of NSCLC are: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. These subtypes start from different types of lung cells and are grouped together as NSCLC because their treatment and prognosis are often similar. Few other subtypes of NSCLC are adenosquamous carcinoma and sarcomatoid carcinoma, which are much less common.

2. Small cell lung cancer (SCLC)

About ten to fifteen percent of all lung cancers are SCLC. It is sometimes known as oat cell cancer. This type of cancer tends to grow and spread faster than NSCLC. About 70% of the people with SCLC will have cancer that has already spread at the time they are diagnosed. As this type of cancer grows quickly so it tends to respond well to chemotherapy and radiation therapy. But unfortunately, cancer in most people will return at some point. 

Some other types of lung tumours are lung carcinoid tumours, adenoid cystic carcinoma, lymphomas, and sarcomas, as well as benign lung tumors such as hamartomas are rare.

There are cancers that start in organs like breast, pancreas, kidney, or skin and can sometimes spread to the lungs but these are not lung cancers. 

Symptoms of lung cancer

Early symptoms are:
- Worsening of cough
- Coughing up phlegm or blood
- While breathing deeply, laughing, or coughing chest pain worsens.
- Hoarseness
- Shortness of breath
- Wheezing
- Weakness and fatigue
- Loss of appetite and weight loss

Some recurrent respiratory infections are pneumonia or bronchitis. When cancer spreads, additional symptoms occur and it depends upon where new tumour form like lymph nodes particularly in the neck or collarbone, bones particularly in the back, ribs or hips, etc.

Facial nerves are also affected if tumours are at the top of the lungs and lead to drooping of one eyelid, small pupil, or lack of perspiration on one side of the face. These symptoms together are known as Horner syndrome. It can also cause pain in the shoulder.

In paraneoplastic syndrome, lung cancer sometimes creates a substance similar to hormones and causes various symptoms like muscle weakness, nausea, vomiting, fluid retention, high blood pressure, high blood sugar, confusion, seizures, coma, etc.

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How is lung cancer caused?

About 90% of lung cancer occurs due to smoking. When smoke is inhaled into your body from that moment it starts damaging the tissues of the lungs. The lungs can repair the damage but continuous smoking makes it difficult for the lungs to keep up the repair. When cells damage, they begin to behave abnormally and may increase the development of lung cancer. With heavy smoking mostly small-cell lung cancer is associated. When smoking is reduced then it lowers the risk of lung cancer over time.

According to the American Lung Association, the second cause of lung cancer is exposure to radon which is a naturally existing radioactive gas. 

Another cause includes breathing in other hazardous substances mainly for a long period of time. Mesothelioma is a type of lung cancer that is always caused due to exposure to asbestos.

Some other substances that cause lung cancer are:
- Arsenic
- Cadmium
- Chromium
- Nickel
- Uranium
- Some petroleum products
It has also seen that sometimes, there’s no obvious cause for lung cancer.

Lung Cancer: Stages

Stages of cancer represent how cancer spread and also help guide treatment.

If lung cancer is treated in the early stages before it spreads then the chance of successful or curative treatment is much higher. Lung cancer does not cause any obvious symptoms in the early stages. After it spreads, the diagnosis comes.

Stages of Non-small cell lung cancer

Stage 1: Cancer is diagnosed in the lung, but it has not spread outside the lung.

Stage 2: Cancer is diagnosed in the lung and nearby lymph nodes.

Stage 3: In the middle of the chest, cancer is in the lung and lymph nodes.

Stage 3A: Cancer is diagnosed in lymph nodes, but only on the same side of the chest where cancer first started growing.

Stage 3B: Cancer has spread to lymph nodes on the other side of the chest or above the collarbone to lymph nodes.

Stage 4: To both lungs, cancer spread and into the area around the lungs, or to distant organs.

There are two main stages of Small-cell lung cancer (SCLC). In the limited stage, cancer is found in only one lung or nearby lymph nodes on an equivalent side of the chest.

In an extensive stage, 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, and to distant organs.

It has also seen that during the diagnosis, two out of three people suffering from SCLC are already in an extensive stage. 

Lung Cancer: Treatment

Small cell lung cancer treatments include surgery, chemotherapy, radiation therapy, immunotherapy, laser therapy, which uses a laser beam to kill cancer cells, endoscopic stent placement.

For non-small cell lung cancer treatments include surgery, radiation therapy, chemotherapy, targeted therapy, immunotherapy, laser therapy, photodynamic therapy (PDT), cryosurgery, electrocautery. 

Lung cancer can be prevented by quitting smoking, lower the exposure to hazardous substances at work, and lower the exposure to radon.

So now you may have come to know about lung cancer, causes, symptoms, stages, treatment, etc.

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