What is Lung Cancer
Lung cancer arises in the lung tissues and develop like other cancers, with the disruption in the normal processes of cell division, leading to abnormal, uncontrolled cell growth into tumour mass.
Any such abnormal growth in the body can directly invade surrounding tissues and organs, like lymph nodes and has the potential to grow back after being removed and spread to different body parts like brain, liver.
Incidence & Epidemiology
- Worldwide, lung cancer is the leading cause of cancer related deaths, with more than 1 million cases diagnoes yearly
Main types of Lung Cancer
Symptoms
Shortness of Breath
If cancer grows to block the major airways, patients may experience shortness of breath.
Coughing up Blood
Lung cancer can cause bleeding in the airway, which can cause you to cough up blood.
Cancer that spreads to other parts of the body (Metastasis)
Lung cancer often spreads (metastasizes) to other parts of the body, such as the brain
Fluid in the Chest
Pleural Effusion
Pain
Advanced lung cancer that spreads to the lining of a lung or to another area of the body, such as bone, can cause pain
Risk Factors
Smoking
Your risk of lung cancer increases with the number of cigarettes you smoke each day.
Expposure to Radon Gas
Unsafe levels of radon can accumulate in any building, including bones
Exposure to Asbestos and other Carcinogens
Workplace exposure to asbestos and other substances known to cause cancer such as arsenic, chromium and nickel.
Exposure to Second hand Smoke
Family history of Lung Cancer
Diagnosis
Screening for Lung Cancer
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Testing a healthy individual at high risk for developing lung cancer who has no symptoms of lung cancer in hopes of finding lung cancer at a stage that it can be cured.
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People with an increased risk of lung cancer may consider annual lung cancer screening using low-dose CT scans. This reduce the number of people who die from lung cancer with acceptable risks when performed in a high quality setting.
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Lung cancer screening is generally offered to people 55 and older who smoked heavily for many years and are otherwise healthy.
Stages of Lung Cancer
Stages
Description
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1
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The tumor size is less than 5 cms and it is limited to lungs only.
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There is no involvement of lymph nodes.
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2
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Tumor size is more than 5 cms
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Lymph nodes are involved
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Making part of the lung collapse
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Larger than 7cm with no involvement of lymph nodes
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In the main airway (bronchus) close to where it divides to go into each lung
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Any size but there is more than one tumor in the same lobe of the lung
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spread to chest wall, muscle under the lung (diaphragm), the phrenic nerve, or the layers that cover the heart/p>
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3
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Complete lung collapse
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Spread into lymph nodes on the opposite side of the chest
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Involvement of major structures in the chest include the heart, the wind pipe (trachea), the food pipe (oesophagus) or a main blood vessel
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Has spread into the chest wall, the muscle under the lung (diaphragm), or the layers that cover the heart (mediastinal pleura and parietal pericardium)
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4
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If the cancer has spread to a distant part of the body such as the liver, bones or the brain.
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Lung Cancer Lab tests: NCC Recommendations
Biomarker testing
Biomarker testing includes tests of genes or their products (proteins) within cancer cells. It is done because not all lung cancers are alike. Lung cancer can differ between people by which genes are present. Biomarker testing is used to plan treatment for metastatic lung cancers.
EGFR mutations
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EGFR (epidermal growth factor receptor) a surface receptor protein. Mutations in the gene that controls EGFR cause the receptors to be overactive. EGFR overactivity causes new cancer cells to form quickly.
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EGFR mutation testing is advised for metastatic lung adenocarcinomas, large-cell lung carcinomas, and unknown subtypes. Very few squamous cell carcinomas have overactive EGFR mutations.
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However, EGFR mutation testing of metastatic squamous cell carcinomas may be considered. It may be done for people who never smoked and for mixed histology. Testing for EGFR is approved both from a tissue sample or blood sample.
ALK gene rearrangement
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For some lung cancers, the growth of the cancer cells is caused in part by an ALK (anaplastic lymphoma kinase) gene rearrangement. A gene rearrangement is the fusion of one gene with another gene to create a new gene. In some lung cancers, ALK fuses with EML4. The ALK-EML4 fusion gene makes an overactive ALK surface receptor that helps lung cancer cells grow.
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ALK testing is advised for metastatic lung adenocarcinomas, large-cell lung carcinomas, and unknown subtypes. Very few squamous cell carcinomas have an ALK gene rearrangement.
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However, ALK testing of metastatic squamous cell carcinomas may be considered. It may be done for people who never smoked and for mixed histology. An ALK rearrangement does not usually occur with EGFR, ROS1, and KRAS mutations.
ROS1 gene rearrangement
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About 2 out of every 100 lung adenocarcinomas (2%) consist of cells with a ROS1 gene rearrangement. Several genes have been found to fuse with ROS1. Like ALK, the ROS1 fusion gene makes an overactive ROS1 surface receptor that helps lung cancer cells grow.
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ROS1 testing is advised for metastatic lung adenocarcinomas, large-cell lung carcinomas, and unknown subtypes. It may be considered for people with squamous cell carcinoma. An ROS1 rearrangement does not usually occur with EGFR, ALK, and KRAS mutations.
BRAF V600E mutation
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A BRAF V600E mutation occurs in 1 to 2 out of every 100 lung adenocarcinomas (1%2%). Commonly, people with this mutation smoke or have smoked.
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Mutations in the BRAF gene causes the BRAF protein (kinase) to be overactive. BRAF overactivity causes new cancer cells to form quickly.
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BRAF testing is advised for metastatic lung adenocarcinomas, large-cell lung carcinomas, and unknown subtypes. It may be considered for people with squamous cell carcinoma. BRAF mutations typically do not occur with EGFR and ALK mutations.