Lung Cancer

Lung Cancer overview and Definition

The cancer cells are the cells which multiplies out of control. The multiplication of the cancer cells in the lungs leads to the development of the lung cancer.

Structure of Lung Cancer

The lung is a spongy organ and it constitutes a pair of lung. The lung has 3 lobes. The left lung has 2 lobes and it is smaller in size since the Heart covers the most part of the left lung. The lung acts as a major system in the exchange of oxygenated (pure blood) and deoxygenated blood (impure blood). When we inhale the oxygenated air is inspired and it reaches the trachea via nose and then it get passed to the bronchi (a trachea gives into branch which is known as bronchi), the bronchi divides in to smaller bronchi and these smaller bronchi further divides into bronchioles. The bronchioles again divides into the microstructure called alveoli. These alveoli takes part in the exchange of oxygen and carbondioxide from the blood. The lung is lined by the pleura which and it protects the lung and it also help the lung to slide back and forth against the chest wall. Below the lung one can find the Diaphragm which seperates the lung and abdomen and help in the contraction and expansion of the lung during respiration process.

lung during respiration process.

The cancer mostly occur in the cells lining the bronchi, bronchioles or it might take part in the alveoli.

Types of lung cancer:

Small cell Lung cancer(SCLC):

There are two types of small cell lung cancer: small cell carcinoma and mixed small cell/large cell cancer or combined small cell lung cancer. A small cell lung cancer is often associated with the cigarette smoking. Small cell cancer is usually treated with chemotherapy.

Non small cell lung cancer(NSCLC):

It is more common type of the cancer. It accounts for 80 percent of the lung cancer cases. This type of cancer usually grows and spreads to other part of the body more slowly than other small cell lung cancer does. There are three types of non small cell lung cancer. It includes:


It is a form of non small cell lung cancer and it is often found on the outer surface of the lung such as in the pleura which lines the lung , in the cells of epithelial tissues which makes the cavities and forms the glands.

Squamous cell carcinoma:

This type of cancer is mostly seen in the bronchus.

 Large cell carcinoma:

A form of non small cell lung cancer than can occur at any part of the lung and tends to grow and spread faster than adenocarcinoma or squamous cell carcinoma.

Pancoast tumour:

These are the type of the non small cell lung cancer that often develops in the superior sulcus or on the upper part of the lungs. They are often treated with chemotherapy or surgery.


They are rare tumour and they tend to grow slowly than anyother tumour. They are made of specialized cells called Neuroendocrine cells. They are classified as typical or atypical carcinoids. They are slow growing tumour and they are treated with surgery.


Clinical signs & symptoms

The main symptoms include:

Chronic cough for 2-3 weeks

A longstanding cough that gets worse

Chest infections that keep coming back

Coughing up with blood

An ache or pain while breathing or coughing

Persistent breathelessness

Persistent tiredness

Lack of energy

Lack  of apetite



Differential Diagnosis

Physical examination:

The doctor might check for the signs and symptoms that correlate the lung cancer.

Imaging test:

Chest Xray:

The chest x ray predicts any abnormal area in the lungs

Computed tomography:

It reveals the slice of the lung. It uses both the combination of x ray and computer aided device.

It helps to analyse the size, shape and position of any lung tumour and also it helps in the detection of enlarged lymph nodes.

It also looks for any masses in the adrenal gland, liver, brain and other organs.

 CT guided needle Biopsy:

CT scan might be used to guide a biopsy needle into this  area to get the tissue for lung cancer.

MRI scan:

It uses the soft tissue image of the organ. It uses the both the magnet and radiowaves.

It often reveals whether the cancer cells has spread to the brain or spinal cord.

Positron emmisison tomography:(PET)

 A radioactive form of sugar in injected into the blood and the positron are emitted to reveal the cancer site.

They can detect if the cancer cell has spread anywhere.

Bone scan:

A low level radioactive material is injected into the blood and collects mainly in abnormal areas of blood.

Sputum cytology:

Sputum(mucus cough up from the lungs) is checked. The best way to obtain the sputum is from early morning sample. This test helps to find out the cancer in the major airways of lungs such as squamous cell lung carcinoma.


A needle is inserted between the ribs and the sample from pleural fluid is taken.

Fine needle aspiration (FNA) biopsy:

A needle is used to aspirate small fragments of tissues. It is used for cancer in the lymph node in the lungs.

Transtracheal or transbrochial FNA:

It is done by passing the needle through the walls of the trachea or bronchi during bronchoscopy or endobronchial ultrasound.

Transthoracic needle biopsy:

It is used to find out if the tumour is present outside the tumour.


It  a procedure that uses a lighted tube inserted behind the sternum (breast bone) and in front of the windpipe to look at and take tissue samples from the lymph nodes along the windpipe and the major bronchial tube areas. If some lymph nodes can’t be reached by mediastinoscopy, a mediastinotomy may be done so the surgeon can directly remove the biopsy sample. For this procedure, a slightly larger incision (usually about 2 inches long) between the left second and third ribs next to the breast bone is needed.


Bronchoscope is a thin lighted instrument used to view the lungs. The physician passes the tube through the trachea then the bronchus and alveoli are viewed clearly.


The prognosis of lung cancer is very poor. With the stage 4 cancer it is only 6%. With stage it is 62%.


Avoid smoking

Avoid tobacco usage

Avoid air pollution arear

Avoid the exposure to the radiation and chronic chemicals

Follow healthy diet.