Lung Cancer
In 2018, there were 48,698 new lung cancer cases among Indian males and 19,097 new cases among Indian female. Lung cancer has a high mortality rate of 63,475 deaths reported across India in 2018 due to lung cancer.
Types Of Lung Cancer
Doctors that treat cancer have classified Lung cancer into the following types:
Small Cell & Non-small cell lung cancer: Non-small cell lung cancer is a form of lung cancer that originates from lung tissue whereas, Small cell lung cancer almost always begins in the bronchi (the tubes or airways in the centre of the chest transporting air to the lungs). Small lung cancer occurs almost exclusively in smokers and is less common than non-small cell lung cancer.
Non-small cell lung cancer includes several subtypes such as squamous cell carcinoma, adenocarcinoma and large cell carcinoma. Adenocarcinoma (40% of all lung cancers; develop from mucus-producing cells) Squamous cell carcinoma (25–30% of all lung cancers; develop in cells lining the airways and is usually caused due to smoking), Large cell or undifferentiated carcinoma (10–15% of all lung cancers consists; named from the way cells appear under a microscope).
Staging Of Lung Cancer
If you are diagnosed with lung cancer, your doctor will run more tests to determine the extent (stage) of your cancer. The stage of your lung cancer is based on the size and spread of the tumour and helps the clinical team decide which treatments are optimum.
Non-Small Cell Cancer Staging
Occult Cancer: The main tumour can’t be assessed or cancer cells are seen in a sample of sputum but the cancer isn’t found with other tests
- Stage 0: Tumour is restricted only in the top layers of cells in the air passages, but it has not invaded deeper into the lung tissues, to the lymph nodes, or to distant parts of the body.
- Stage I: Stage IA (The tumour is between 1 and 3 cm across, it has not reached the membranes that surround the lungs with no spread to lymph nodes or distant sites in the body), Stage IB (The tumour is between 3-4 cm across, has grown into a main bronchus, has grown into the membranes surrounding the lungs or is partially clogging the airways with no spread to lymph nodes or distant sites in the body).
- Stage II: It is divided into two subtypes. Stage IIA (The tumour is 4-5 cm, has grown into a main bronchus, has grown into the membranes surrounding the lungs or the tumour is partially clogging the airways with no spread to lymph nodes or distant sites in the body). Stage IIB (The tumour is less than 3 cm across, has not grown into the membranes that surround the lungs, and does not affect the main branches of the bronchi. It has spread to lymph nodes within or around the lung on the same side as the cancer. The cancer has not spread to distant parts of the body OR the tumour is 5-7 cm across, has grown into the inner lining of the chest wall, the phrenic nerve, or membranes of the sac surrounding the heart (parietal pericardium) or has two or more separate tumour nodules in the same lobe of a lung)
- Stage III: It is divided into three subtypes. Stage IIIA (The tumour is less than 3 cm, 3-5cm or greater than 7cm across, may or may not have grown into the membranes that surround the lungs, may or may not affect the main branches of the bronchi. The lymph nodes around the point where the windpipe splits into the left and right bronchi are affected on the same side as the main lung tumour but the cancer has not spread to distant parts of the body) Stage IIIB (The tumour is less than 3 cm, 3-5cm or greater than 7cm across, may or may not affect the bronchi, has spread to the lymph nodes, may or may not partially clog the airway and may or may not have spread to the other tissue in the chest.) Stage IIIC (The tumour has one or more of the following features greater than 5 cm has grown into the chest wall, the inner lining of the chest wall, affects the phrenic nerve, or the sac surrounding the heart, There are 2 or more separate tumour nodules in the same lobe of the lung, has spread to lymph nodes but has not spread to distant parts of the body).
- Stage IV: It has two subtypes. Stage IVA (The cancer can be any size, may or may not have grown into nearby structures and lymph nodes. In addition, any of the following: spread to the other lung, cancer cells are found in the fluid around the lung or in the fluid around the heart or has spread as has spread as a single tumour outside of the chest to the liver, bones, or brain), Stage IVB (The cancer can be any size and may or may not have grown into nearby structures, may or may not have reached nearby lymph nodes and has spread to more than one tumour outside the chest, to other organs such as the liver, bones, or brain).
Small Cell Cancer staging
Stage 0: Also known as in-situ cancer wherein the cancer has not grown into nearby tissues or spread outside the lung
Stage I: The tumour is small and has not spread to any lymph nodes. It is divided into two sub-stages based on the size: Stage IA (3cm or less in size) Stage IB (3 cm to 4 cm across)
Stage II: It is divided into 2 sub-stages: Stage IIA (the tumour is between 4 to 5cm and has not spread to the nearby lymph nodes) Stage IIB l(tumour is 5 cm or less and has spread to the lymph nodes OR is more than 5 cm wide that has not spread to the lymph nodes)
Stage III: It is classified in to three subtypes
Stage IV: The lung cancer has spread to more than one area in the other lung, the fluid surrounding the lung or the heart, or distant parts of the body through the bloodstream. Once cancer cells get into the blood, the cancer can spread anywhere in the body. Stage IV is divided into 2 substages:
- Stage IVA (cancer has spread within the chest and/or has spread to one area outside of the chest)
- Stage IVB (cancer has spread outside of the chest to more than 1 place in 1 organ or to more than 1 organ).
Sources: Globocan; MedicineNet ; European Society of Medical Oncology (ESMO); Cancer India; American Cancer Society; Mayo Clinic; Cancer.Net;