Lung is basically two sponge-like organs in our chest that inhales oxygen and exhales carbon dioxide in the air.  Lung cancer is when the cell growth in the lungs becomes uncontrollable.

People who smoke has the greater chance of developing lung cancer. But lung cancer can be found in people who never smoked in their lives. The risk of lung cancer increases as per the duration and frequency of smoking. If anyone quits smoking even after doing it for a long time, the risk of lung cancer gets significantly less.

There are basically two types of lung cancer – Small cell lung cancer and Non-small cell lung cancer. Mostly, small cell lung cancer exclusively occurs to people who smoke a lot. Whereas non-small lung cancer is more common type of lung cancer. It is an umbrella term for many kinds of lung cancers like squamous cell carcinoma, adenocarcinoma and large cell carcinoma.

Though lung cancers don’t show major symptoms in the early stages, as it advances, few symptoms become prominent like:

• A new cough that doesn't go away
• Coughing up blood, even a small amount
• Shortness of breath
• Chest pain
• Hoarseness
• Losing weight without trying
• Bone pain
• Headache

Lung cancers are typically classified in five stages. In Stage 0, cancer is just started to form and restricted to the area of origin.

Stage 1, when the cancer is a small tumor and has not spread to any other nodes or lymph. In this stage the size of the tumor is not more that 3 cm and it is very much possible to get removed by surgery.

In Stage 2, the size of the tumor is 4 cm to 5 cm, sometime larger than that. In this stage too, removal of tumor with a surgery is possible. But more treatments may be needed later.

Stage 3 lung cancer describes the cancer when it is spread to nearby lymph and lung areas. In this stage the size of the tumor is quite big and due to the spread, it is mostly impossible to remove it by surgery. Hence patient is offered other systematic therapies and radiation therapies.

Stage 4 means lung cancer has spread to different parts of lung, nearby organs and other distant body parts through bloodstream. In this stage, it is completely impossible to remove the cancer cells or tumors by surgery are it has spread to entire body. Depending on the case, doctors suggest proper available therapies like chemotherapy, radio therapy and immunotherapy.