How is Lung Cancer Diagnosed?

To help find the cause of symptoms, the doctor evaluates a person’s medical history, smoking history, exposure to environmental and occupational substances, and family history of cancer. The doctor also performs a physical examination and may order a chest X-ray and other tests

Patient’s History

If the doctor suspects lung cancer, they will

    Investigate your medical history
    Perform a thorough physical examination
    Order further specialised medical tests

As part of your medical history, your doctor will ask about:

    If you smoke or have smoked previously
    Your occupation and place of work.
    If you’ve been exposed to occupational hazardous substances or radiation
    Whether you have a family history of lung cancer

Other Signs and Symptoms of Lung Cancer

Horner’s syndrome

A tumour in the upper part of the lungs sometimes injures a nerve passing from the upper chest into the neck. Doctors sometimes call these cancers Pancoast tumours. A common symptom of a Pancoast tumour is a severe pain in the shoulder. These tumours can also cause Horner’s syndrome. Horner’s syndrome is a medical term for a group of symptoms which consist of drooping or weakness of one eyelid, reduced or absent perspiration on the same side of the face and the pupil in the eye on the affected side becoming smaller.

Paraneoplastic syndromes

Other lung cancers produce hormone-like substances which enter the bloodstream causing problems with remote tissues and organs. The cancer doesn’t have to spread to those tissues or organs for them to be affected.

These secondary problems are called Paraneoplastic or tumour-related syndromes. Often these symptoms may be the first warning sign of early lung cancer. Unfortunately these symptoms affect other organs, so patients and their doctors often suspect other diseases before cancer is tested for.

People with small cell lung cancer and those with non-small cell lung cancer frequently have diverse Paraneoplastic syndromes.

Recognizing Symptoms of Lung Cancer

Symptoms of lung cancer are not as a rule noticeable during early stages of the disease because the first symptoms to appear are frequently comparable to those of other, non-malignant respiratory illnesses.

Although generally lung cancers don’t cause any symptoms until they have spread too far to be cured, there are typical symptoms occurring in some people with early lung cancer.

If someone with early lung cancer was to go to their health care consultant when they first noticed their symptoms, there would be a possibility their cancer would be diagnosed and treated whilst at a curable stage, so anyone experiencing any of the following problems or symptoms should seek medical attention immediately.

Common signs and symptoms of lung cancer include:

    A cough that doesn’t disappear and gets worse over a period of time
    Constant pain in the chest
    Coughing up blood
    Frequent problems with pneumonia, bronchitis or other related respiratory problems.
    Puffiness round the neck and face
    Gross exhaustion
    Shortness of breath.
    Wheezing and/or gasping

Risk Factors for Lung Cancer

A risk factor is something that increases your chance of getting a disease such as cancer. But different types of cancer have different risk factors.

For example, if you sunbathe unguarded from the sun, you run the risk of skin cancer as exposure to strong sunlight is a risk factor for this type of cancer.

There are several risk factors which can make you more likely to develop lung cancer:
Researchers have discovered there are several causes of lung cancer and most of them are related to smoking.

Risk factors for small cell lung cancer include:

    Smoking cigarettes are the most well-known cause of lung cancer. This includes the smoking of cigarettes, cigars, or pipes in the past.
    Being exposed to second hand smoke.
    Being exposed to asbestos or radon.

Up to 90 percent of lung cancer patients are or have been smokers. Many of the 10% left have been exposed to second-hand cigarette smoke.

There are dangerous substances, called carcinogens in tobacco and over time they damage the cells in the lungs. These damaged cells can then become cancerous. If you stop smoking before a cancer starts to develop, the damaged lung tissue has a chance to gradually return to normal.

Non-small Cell Lung Cancer

Nonsmall cell lung cancer is more widespread than small cell lung cancer, and generally it grows and spreads more gradually. The remaining lung cancers are all non-small cell (NSCLC).

There are three sub-types of NSCLC. The cells in these sub-types fluctuate in size, shape, and chemical make-up.

Squamous cell carcinoma: About 25% – 30% of all lung cancers are Squamous cell carcinomas. They are linked with a history of smoking and tend to be found centrally, near a bronchus.

Squamous cell carcinoma generally starts in the bronchi and doesn’t usually spread as rapidly as do other lung cancers

Adenocarcinoma: This type of cancer accounts for about 40% of lung cancers and is typically found in the outer region of the lung. Adenocarcinoma is more commonly found in women than in men.

Large-cell undifferentiated carcinoma: This kind of cancer accounts for about 10% – 15% of reported lung cancers. It appears in any part of the lung and tends to grow and spread quickly throughout the body ensuing in a poor prediction of recovery.

Large cell carcinoma is any lung tumor that cannot be classified

Small Cell Lung Cancer

There are three types of small cell lung cancer. These three types include lots of different types of cells. The cancer cells of each of these grow and multiply in different ways.

The types of small cell lung cancer are named after the different types of cells found in the tumour and how they look when examined under a microscope:

    Mixed small cell/large cell carcinoma.
    Combined small cell carcinoma.

Small cell lung cancer is occasionally called oat cell cancer and is less widespread than non-small cell lung cancer. SCLC can spread itself widely throughout the body. This means management of the illness has to include drugs to kill the widespread disease. Small cell carcinoma creates its own hormones, which then can alter body chemistry.

Although each cell is small, they multiply quickly, forming large tumours, and spreading to lymph nodes and other organs such as the bones, brain, adrenal glands, and liver. This type of cancer frequently starts in the bronchi towards the centre of the lungs.

Small cell lung cancer is nearly always caused by smoking. It is very unusual for someone who has never smoked to have small cell lung cancer.

Causes Of Lung Cancer

As cigarette smoking is a major cause of lung cancer nowadays, it is important to appreciate how smoking affects and injures the lungs. This is because smoke inhalation damages the normal cleaning process by which the lung protects itself from injury.

The bronchi which conduct inhaled air to the lung tissues are lined with a single coating of cells on which lies a defensive coating of mucus.
The hair-like cilia on these cells beat in a regular rhythm to advance mucus upwards continually from the lung removing any inhaled particles which may have become trapped in the process.

The competence of this cleaning mechanism is damaged very quickly by smoke inhalation. The cilia disappear and the coating they lie in thickens in an attempt to protect the fine underlying tissues from injury. Once this damage has occurred, the lung can no longer keep itself uncontaminated.

As a result, the cancer-producing agents in cigarette smoke remain ensnared in the mucus on the surface lining of the airway. They then pass into the cells before being removed by coughing which is the only cleansing mechanism remaining.

Once they are within the body, these chemicals, and their by-products, alter the very nature of the cells in the lungs slowly and increasingly until finally cancer develops.

Lung cancer

Pulmonary vessels, seen in a dorsal view of the heart and lungs.Most lung cancer starts in the cells lining the main air passages, or bronchi. In their cancerous state, these cells lack cilia which are tiny hair like substances which normally catch and remove foreign particles inhaled into the lungs.

Mucous in the lungs which is usually cleared by bronchial cilia then becomes trapped, blocking air passages and causing respiratory problems.

There are several different types of cancer affecting the lungs; the principal cancers are described below.

The first three types of cancer start in the lining membrane of the airway in the areas more exposed to inhaled pollutants.

Squamous cell cancer represents the leading number of lung cancers (approximately 40%-45%).

Small cell cancers account for 15%-20% of all lung cancer. This is because it spreads rapidly from its characteristically central location.

Large cell undifferentiated cancer is discovered in about 5%-10% of lung cancer cases.