Cancer is a disease where some cells grow out of control, taking over normal cells and organs in the body. Lung cancer is cancer that starts in the lungs. It is also called primary lung cancer. If it starts in another part of your body and spreads to affect your lung, it’s called secondary lung cancer.

There are two major types of primary lung cancer. Each type of lung cancer grows and spreads in different ways and may be treated differently.

Non-small cell lung cancer

This is the most common type of lung cancer. It usually spreads more slowly than other lung cancers. There are three major types of non-small cell lung cancer:

• Squamous cell carcinoma
• Adenocarcinoma
• Large cell carcinoma

Small cell lung cancer

This is a less common type of lung cancer and it spreads faster than non-small-cell lung cancer. Small cell lung cancer is named for the size of cancer cells, which can only be seen under a microscope.

Anyone can get lung cancer. Lung cancer happens when cells in the lung mutate or change. Various factors can cause this mutation (a permanent change in the DNA sequence of a gene) to happen. Most often, this change in lung cells happens when people breathe in dangerous, toxic substances.

Around 90% of cases occur in people who smoke or who used to smoke. Your risk of getting lung cancer increases with the number of cigarettes you’ve smoked and the number of years you’ve been a smoker. If you stop smoking, the risk gets lower over time.

Some people who have lung cancer have never smoked a day in their lives. Their cancer may be caused by something else, like:

• Second-hand smoke. People who regularly breathe second-hand smoke have almost double the risk of getting lung cancer than people who stay away from smoke¹. It’s a fact: Non-smokers who live or work in smoky air can get lung cancer from second-hand smoke.
• Radon. Radon is a colourless, odourless gas found in the soil. Radon can enter buildings through cracks in the foundation or insulation, or through drains or walls. Radon can get trapped in basements and other places that don’t have a lot of air flow (fresh air). People who have a high exposure to radon are at higher risk of lung cancer.
• Asbestos. Asbestos is a heat-resistant mineral found in some workplaces and homes. It has been used in brake pads, insulation, siding, and many other products. People who have a high exposure to asbestos are at higher risk of lung cancer.

Other toxic products: uranium, arsenic, some petroleum products may also increase the risk of developing lung cancer.

There often aren’t any symptoms of lung cancer until a tumour becomes quite large. This means it might only be discovered when you have an X-ray or scan for a different reason.

As your condition progresses, you may begin to experience symptoms, such as:

• a cough
• feeling out of breath
• chest pain
• feeling tired
• appetite loss
• weight loss
• a hoarse voice
• blood in your mucus or phlegm

People with these symptoms could have lung cancer, or it could be something else. If you have these symptoms, you should see your doctor.

Many tests and exams used to diagnose lung cancer. The doctor will ask you about your symptoms and medical history. They might also examine you. The doctor will explain the results of any tests you’ve had, and will tell you what further tests you need.

Your Medical History. Your doctor may ask:

• What medical problems have you had?
• Have you smoked? How much and for how long? Have people around you smoked?
• Where have you lived and worked, what kind of work have you done?
• What is your family history of cancer?
• What symptoms have you noticed?

Physical Exam

Imaging Tests

Your doctor might order imaging tests that may help find lung cancer. Imaging tests make pictures of the inside of your body. These pictures help doctors to find lung cancer, to see if it has spread, to see if treatment is working or to find a cancer that has come back after treatment. These tests include:

• Chest X-ray
• Computed tomography (CT) scan
• Positron emission tomography (PET) scan
• Bone scan

Procedures

To see if something suspicious is actually lung cancer, the doctor must study tissue or fluid from or around the lung. Many different procedures allow doctors to remove cells from the body and look at them under a microscope to determine if they are cancer. These tests include:

• Bronchoscopy. You may need to be sedated (to “go under” general anesthesia) for this test. The doctor slides a thin, flexible tube (a bronchoscope) through your mouth or nose and into your lungs.
• Endobronchial ultrasound (EBUS). bronchoscope (a thin, lighted, flexible tube) is fitted with an ultrasound device (a device that uses sound waves to make pictures of the inside of your body) at its tip. It is passed down into the windpipe to look at nearby lymph nodes and other structures in the chest. This is done with numbing medicine (local anesthesia) and light sedation.
• Endoscopic esophageal ultrasound (EUS). This test is much like an endobronchial ultrasound, except that an endoscope (a lighted, flexible tube) is used. It is passed down the throat and into the esophagus.
• Mediastinoscopy and mediastinotomy. First, you will be put under general anesthesia (in a deep sleep). The doctor makes a small cut in your neck and inserts a thin tube. The tube collects fluid samples and biopsies (pieces of tissue) from the lymph nodes near your throat and lungs. This test helps your doctor know if the cancer has spread to any of your lymph nodes
• Thoracentesis. This test is done to check whether fluid around the lungs is caused by cancer or by some other medical problem. A needle is placed between the ribs to drain the fluid. The fluid is checked for cancer cells.
• Thoracoscopy or video-assisted thoracic surgery (VATS). A small cut is made in the chest. The surgeon then uses a thin, lighted tube connected to a video camera and screen to look at the space between the lungs and the chest wall. The surgeon can see small tumors on the lung or lining of the chest wall and can take out pieces of tissue to be looked at under the microscope.
• Sputum cytology. The doctor collects your sputum (the phlegm you cough up) and tests it for cancerous cells.
• Fine needle aspiration (FNA). The doctor gives you local anesthesia so you don’t feel pain, and then slides a thin needle into your chest. The needle collects a small piece of the tumour, which doctors examine under a microscope.

Screening is looking for cancer before you have any symptoms, which can help find cancer at an early stage when it may be easier to treat.

Data show that screening for lung cancer with low-dose computed tomography (LDCT) reduces the risk of dying from lung cancer in the high-risk population studied. Other screening tests such as chest X-rays and sputum cytology have not been found to be effective, and are not recommended for screening.

If you meet the following criteria, you are considered to be at “high risk” for developing lung cancer and screening is recommended:

• 55-80 years of age
• Have a 30 pack-year history of smoking (this means 1 pack a day for 30 years, 2 packs a day for 15 years, etc.)
• AND, are a current smoker, or have quit within the last 15 years

Staging means finding out if and how much the lung cancer has spread and helps shape your recommended treatment plan. Your treatment plan and the general outlook for your recovery depend upon the stage of your lung cancer.

Three factors are used to determine lung cancer stage (sometimes referred to as the TNM classification system). The stage of your lung cancer is determined by a combination of all of these factors.

• T – Tumor size and location
• N – Regional lymph node involvement. Lymph nodes are small ball-shaped immune system organs distributed throughout the body. It is important to know whether the lung cancer has spread to the lymph nodes around the lung.
• M – Metastasis status. Metastasis status refers to which organs the cancer has spread.

Non-small cell lung cancer stages range from one to four, usually expressed in Roman numerals (I through IV). The lower the lung cancer stage, the less the cancer has spread. Small cell lung cancer is described using two stages: limited and extensive.

Different treatments work for different types of lung cancer. To decide on treatment for a particular patient, doctors look at:

• The type of cancer the patient has
• The patient’s age and overall health
• The stage the lung cancer is at — whether it has spread to other parts of the body

After looking at those things, doctors may recommend one or more of these treatments:

Surgery

There are many kinds of surgery to remove lung cancer tumours:

Pneumonectomy: doctors remove one entire lung (people can breathe using the remaining lung).

Lobectomy: doctors remove a section of the lung (a lobe).

Segmentectomy or wedge re-section: doctors remove a part of a lobe.

Laser surgery: a high-energy beam of light destroy the cancer cells in a tumour.

Chemotherapy

Chemotherapy is medicine that fights cancer. Some kinds of chemotherapy come in pills. Other kinds are delivered into your bloodstream by intravenous drip (IV), where a machine slowly drips medicine into tubes that go into your veins. Some chemotherapy is given by injection (a shot).

Radiation Therapy

Radiation therapy uses high-energy radiation to kill cancer cells. The radiation can be delivered by a machine that directs the high-energy rays towards the cancer, or by a small radioactive pellet that gets implanted in or near the tumour.