Insight into Lung carcinoma

Hi everyone! Welcome to my first ever blog. In today’s article, our focus is on the second most common cancer in both men and women: Lung cancer. This type of cancer, also known as Lung Carcinoma, is the leading cause of cancer death in Canada. In 2020 alone, it was estimated that 21,000 Canadians would die from it.

What is lung cancer?

It is a type of cancer that begins in the cells of lungs. These cells occasionally go through changes which can result in non-cancerous tumours such as benign tumours and cancerous tumours such as malignant tumours. A malignant tumour is dangerous because it grows uncontrollably and damages the healthy tissue of the lungs. In fact, the cancer can become so large that it can block a major airway and prevent the respiratory system from working effectively.

Cancerous cells can also spread to other parts of the body. This can happen because sometimes a cancerous tumour sheds cells. The cells are carried to different body parts through the bloodstream or natural fluid around the lung tissue called lymph. The quickly growing cells can cause infection or destroy the tissue of the organs they come in contact with. The body parts that can be affected are the bones, lymph nodes, brain or spine and liver.

Note that other types of cancer can spread to the lungs. Even though the cancer is the lungs, the type of tumor is not considered lung cancer.

Types of lung cancers

Lung cancer is categorized into two major types based on the appearance of the cells under the microscope and the type of cell in which the cancer grows. Non-small cell lung cancer is more common than small cell lung cancer.

1- Small cell lung cancer

This type of cancer occurs almost only in heavy smokers. Small cell lung cancer usually starts in cells that line the bronchi in the centre of the lungs. The main types of small cell lung cancer are small cell carcinoma and combined small cell carcinoma. Other types of cancer can spread to the lung, but this is not the same disease as primary lung cancer. A rare type of cancer called pleural mesothelioma is often mistakenly called a lung cancer. Pleural mesothelioma starts in the pleura covering the lung and is very different from cancer that starts in the lung.

2- Non-small cell lung cancer

Non–small cell lung cancer usually starts in glandular cells on the outer part of the lung. This type of cancer is called adenocarcinoma. Non–small cell lung cancer can also start in flat and thin cells called squamous cells. These cells line the bronchi, which are the large airways that branch off from the windpipe (trachea), into the lungs. This cancer is known as squamous cell carcinoma of the lung. Large cell carcinoma is another type of non–small cell lung cancer, but it is less common. There are also several rare types of non–small cell lung cancer such as sarcoma and sarcomatoid carcinoma.

Causes of cancer

1- Smoking

The major cause of lung cancers is smoking, both in smokers as well as in people exposed to secondhand smoke.

2- Radon

Radon is the second leading cause of lung cancer. It is an invisible odorless gas that comes from the natural breakdown of uranium in soil, rock and water. Its evaporation in the atmosphere is not dangerous because the air outside dilutes the amount of radon. However, when radon gets trapped into a closed space like a building or house, it can be very harmful. In fact, a person can be breathing in high levels of radon without knowing it. It is important to acknowledge that smokers in contact with radon are at a very high risk of lung cancer.

3- Air pollution

The following substances are carcinogens (capable of causing cancer in living tissue): Arsenic, chromium, nickel, uranium and some petroleum products.

Other air pollutants are Carbon dioxide, Nitrogen and particulate matter.

4- Inherited genetic mutations

5- Unknown cause

Note that lung cancer can also be found in people who never smoked nor had prolonged exposure to secondhand smoke or other harmful substances. In such cases, there may be no clear cause of lung cancer.

Symptoms

The symptoms of Lung cancer typically don't appear in its earliest stages. It is often discovered when the disease has advanced. It is important to see your doctor if you have these symptoms:

- A cough that gets worse or doesn’t go away

- Coughing up blood, even a small amount

-Hoarseness or other changes in voice

-Difficulty swallowing

-Chest pain that you can always feel and that gets worse with breathing or coughing

-Swollen lymph nodes above the collarbone and in the neck

-Intense bone pain in the back, ribs and hips

-Fluid in the chest, known as Pleural Effusion

Complications

It is important to acknowledge that some symptoms are specific to the type of lung cancer and may cause complications.

Non–small cell lung cancer can cause Horner syndrome.

It is a group of symptoms that occur due to the lung

cancer growing into the nerves at the top of the lung:

Small cell lung cancer causes various syndromes. The syndromes are formed of symptoms that occur due to the metastasis, which is the impact of the cancerous cells on various organs of the human body.

Lambert-Eaton syndrome is caused by the lack of a chemical that transmits messages between muscles and nerves. Symptoms of Lambert-Eaton syndrome include muscle weakness, loss of movement, difficulty chewing, climbing stairs or lifting objects.

Syndrome of inappropriate antidiuretic hormone (SIADH) is when the body makes excessive antidiuretic hormone (ADH). Symptoms of SIADH include cramping, restlessness, confusion, fatigue, nausea and vomiting.

Cushing syndrome is when the body makes high amounts of corticosteroids. It causes high blood pressure, high blood sugar, a round face with thin arms and legs, numbness in arms or legs and may also cause weight gain that causes purple marks on the stomach.

Paraneoplastic cerebellar degeneration is a very rare paraneoplastic syndrome. It is caused when the body’s immune system attacks the cells of the central nervous system in response to an abnormal reaction. It includes dizziness, nausea, balance issues, blurred vision, rapid eye movements, shaking and speaking difficulties.

That is it for today. This much detail was needed to make the concepts clear and I hope it broadened your horizons on lung cancer. Stay safe but make sure to enjoy the weather!

Fatima Asif