The four types of lung cancer are based on the cell types and location, as well as how they look under a microscope.
The four types of lung cancer are based on the cell types and location, as well as how they look under a microscope.

Lung cancer is classified into four types, depending on how the cancer cells look under the microscope.

  • Small Cell Lung Cancer (Oat cell lung cancer): This cancer often starts in the bronchi (major airways). Small cell cancers comprise 15% of lung cancers. These are the most aggressive cancers of the lung.
  • Non-Small Cell lung cancer (NSCLC) Adenocarcinoma: This type of lung cancer originates in the cells that normally secrete mucus. These are found in the smaller airways and have a slow growth rate.
  • Non-Small Cell lung cancer (NSCLC) Squamous Cell carcinoma (epidermoid carcinoma): This is the most common form of lung cancer (accounts for 30% of cases).  It is found in the central lung or main airways. This type has the strongest association with smoking.
  • Non-Small Cell lung cancer (NSCLC) Large Cell lung cancer: It may appear in any part of the lung.

How is lung cancer diagnosed?

Doctors use various diagnostic procedures and tests to diagnose lung cancer. These include:

  • A history and physical examination of the patient. This may help in identifying symptoms or signs that may point to lung cancer. 
  • The chest X-ray is usually the first test ordered in the diagnosis of lung cancer. Chest X-rays may reveal problematic areas in the lungs, but cannot confirm the presence of cancer.
  • Computerized tomography (CT) scans may be performed on the chest, abdomen, and/or brain to examine for both metastatic and lung tumors. 
  •  A spiral CT scan can be done as an annual screening test in chronic tobacco smokers between ages 55 and 80.
  • Magnetic resonance imaging (MRI) scans are ordered when precise detail about a tumor's location is needed. 
  • Positron emission tomography (PET) scanning is a specialized imaging technique that uses special (radioactive) drugs to produce a three-dimensional colored image of the tissues within the body. PET scans can check whether a tumor tissue is actively growing and map its location inside the organ.
  • Bone scans are used to create images of bones on a computer screen or on film. Doctors may perform a bone scan to check if the lung cancer has spread to the bones.
  • Sputum cytology:  The sputum of the patient is examined under a microscope to check if there are any malignant cells.  
  • Bronchoscopy: This test involves visualizing the airways through a thin probe inserted through the nose or mouth.  A sample can be removed from the suspicious tissue to be examined in the laboratory.
  • Needle biopsy: Needle is inserted into the chest to remove a small sample of your lung for examination under the microscope.
  • Thoracentesis: This involves the drawing or aspiration of a sample of fluid from the chest with a thin needle . This fluid is examined and a diagnosis is made.
  • Blood tests: While routine blood tests alone cannot diagnose lung cancer, they reveal other abnormalities that occur with lung cancer.
  • Molecular testing: This is an advanced test to find out the genetic composition of a patient’s lung cancer. This helps in giving highly specialized medicines that target a specific protein on the tumor.
  • Major surgical procedures: Surgical methods are the last option when all other tests fail to provide the correct diagnosis. 

QUESTION

Lung cancer is a disease in which lung cells grow abnormally in an uncontrolled way. See Answer

What is the best treatment for lung cancer?

Treatment options for lung cancer may include surgery, radiation, chemotherapy, targeted therapy, immunotherapy, participation in clinical trials, and/or palliative care. 

Doctors can decide the best treatment for a patient depending upon on: 

  • The type of lung cancer
  • The stage of the lung cancer
  • The overall health status of the patient

How long can you live with lung cancer?

Doctors use lung cancer survival rates to predict the percentage of people who survive a certain type cancer for a specific amount of time. It is based on a subset of the population and does not predict the number of years a particular individual will actually survive. However, in a study conducted by Wao H et al, it was found that untreated lung cancer patients live on an average of 7.15 months. 

The survival rates for lung cancer are as follows:

  • The lung cancer’s five-year survival rate (18.6%) is lower than many cancers of other organs, such as colorectal (64.5%), breast (89.6%), and prostate (98.2%).
  • The five-year survival rate for lung cancer is 56% when the cancer is only present in the lung. 
  • If the lung cancer has spread to other organs (metastasis), the five-year survival rate is only 5%.
  • More than half of people with lung cancer die within one year of their diagnosis.

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Medically Reviewed on 8/6/2020
References
Medscape Medical Reference