There are three main types of lung cancer. They are Non-Small Cell Lung Cancer (NSCLC), Small Cell Lung Cancer (SCLC) and Metastatic Lung Cancer.
Non-Small Cell Lung Cancer (NSCLC):
Being the most common form of lung cancer, almost 85% of lung cancers belong to this category. The growth and spread of these cancers are slow in comparison to others. NSCLC has four major subtypes:
Adenocarcinoma: Accounting for almost 40 % of all lung cancer cases, adenocarcinoma is the most common form of lung cancer for both men and women. Adenocarcinoma occurs in the glandular cells that form the lining of the lungs.
Squamous Cell Carcinoma: This form begins in the squamous cells that form the lining of the bronchioles. This accounts for about 25% to 30% of lung cancers.
Large Cell Carcinoma: This can begin anywhere in the lungs and is regarded as a fast-growing NSCLC. Almost 10% of all lung cancers are of this type.
Large Cell Neuroendocrine Tumours: The fastest-growing form of all NSCLCs, they form only 2% of all lung cancers.
Small Cell Lung Cancer (SCLC):
This type of lung cancer grows and spreads far faster than NSCLC. The cells that make up the tumour are small in nature and hence the name.
Metastatic Lung Cancer:
This term applies to any form of lung cancer that has spread to other parts of the body, usually through the lymph nodes or the blood.
Some less-common types of lung cancers are Sarcomatoid carcinoma, Mesothelioma, Granular cell lung tumours, Carcinoid tumours etc.
Non-small cell lung cancers have four stages-
Stage 1 – in this case the tumour is in a single lung and has not spread to any lymph nodes or other distant organs.
Stage 2 - the cancer has spread to the adjacent lymph nodes but has not spread to any distant organs.
Stage 3 - this stage is subdivided to two other stages-
Stage 3a- cancer has not spread to the other lung but involves the lymph nodes in the same side. No spread to other organs.
Stage 3b- In this stage the cancer has spread to the opposite lung and has progressed further above the collar bone to the throat and neck.
Stage 4- this stage is subdivided into two other stages-
Stage 4a- the cancer has spread to other areas of the chest and to other organs as well
Stage 4b- the cancer has reached outside the chest and spread throughout the body
Small cell lung cancer has two stages:
Limited Stage: The cancer has affected only one of the lungs and nearby lymph nodes.
Extensive Stage: The cancer has spread to both lung and other areas of the chest and body.