Lung Cancer is simply the growth of cancerous tumor cells in one or both lungs. These tumor cells can be either malignant or benign in nature. Lung cancer caused by malignant tumors undergo metastasis and spread across the lungs and might spread to other parts of the body either through the lymphatic system or bloodstream if not diagnosed and treated early. Benign cancer tumors do not grow or spread to other parts of the body but remain in their site of origin, which in this case is the lungs.


The major cause of Lung cancer is smoking. This is because smoke from cigarettes contains more than seventy (70) carcinogens and it is the cause of more than 80% of lung cancer cases. Smoking-induced lung cancer is not limited to smokers alone, as non-smokers can also contract from passive smoking. PASSIVE SMOKING is the process in which a non-smoker inhales smokes from a smoker. This can be due to living or working together or even being constantly together during the period the smoker is smoking.

Other causes of lung cancer are:

Radon Gas: a colorless, odorless gas which occurs when radioactive radium is broken down. Radium is the waste product from the decay of uranium in the Earth's crust. It is the second most common cause of lung cancer

Air pollution: inhalation of air pollutants such as industrial wastes, exhaust fumes, fumes from the burning of fossil fuels, traffic exhaust fumes and burning of firewood or charcoal

Genetics: the risk of lung cancer is increased in descendants of people diagnosed with lung cancer and is largely due to gene combination. This is especially more common when there is polymorphism on chromosomes 5, 6 and 15. Others: this includes other causes such as inhalation of asbestos fibers into the lungs; products of combustion(both complete and incomplete), ionizing radiation, toxic gases such as sulfur mustard and methyl ether, and metals such as arsenic and chromium (VI) compounds.


Lung cancers are classified into three types based on their appearance. These classes are:

Small Cell lung cancers (SCLC): this accounts for about 15% of all lung cancer cases. Its cells are made up of dense neurosecretory granules and usually arises from the primary and secondary bronchi. This class of lung cancer spreads rapidly. It is classified into two according to the level of severity and these are Limited Stage (LS) and Extensive Stage (ES).

Non-Small Cell Lung Cancer (NSCLC): this class of cancer accounts for about 80% of all lung cancer cases. It is further sub-classified into three namely: adenocarcinoma which accounts for about 40% of cancer cases and usually occurs in the surface lung tissues; large-cell carcinoma which is about 9% of lung cancer cases and are referred to as large-cell carcinomas because they are big-sized and contain large nuclei, distinct nucleoli and, excessive cytoplasm; and squamous cell carcinoma which refers to about 30% of lung cancer cases and occur near the large airways. At the center of the tumor, there is usually a hollow cavity present. This subclass is classified according to severity using Roman numerals I-IV with I being the least severe and IV the most severe.

Lung Carcinoid tumor: this accounts for less than 5% of lung cancer cases, they grow slowly and rarely spread and are also referred to as lung neuroendocrine tumors.


The presence of one or more of the following signs and symptoms might be an indication of lung cancer and therefore, such an individual should be tested promptly.
  • A persistent cough
  • Chest or shoulder pain (due to a cough)
  • Blood stained sputum
  • Breathing and swallowing difficulties
  • Stridor
  • Hoarse voice
  • Pneumonia or chronic bronchitis
  • Weakness
  • Fever
  • Wheezing
  • Superior vena cava obstruction
  • Weight loss


Lung cancer can be diagnosed through:

  • History and physical examination
  • Blood tests
  • X-ray Imaging of the Chest region
  • Bone Scans
  • Computerized Tomography (CT) Scans
  • Magnetic Resonance Imaging (MRI)
  • Low dose spiral CT Scan
  • Positron Emission Tomography (PET) Scans
  • Sputum Cytology
  • Needle Biopsy
  • Bronchoscopy
  • Thoracentesis
  • Molecular testing


The treatment method of choice in Lung Cancer is dependent on the type of lung cancer, level of severity and
The treatment methods available for lung cancer are:

  • Surgery
  • Chemotherapy
  • Radiotherapy
  • Targeted therapy
  • Radiofrequency ablation
  • Palliative care
  • Bronchoscopy
  • Immunotherapy
  • Experimental therapy