Typically, the survival rate for stage I lung cancer is anywhere from 70 to 92 percent, depending on the type. Early diagnosis and treatment can improve the outlook.
Lung cancer, the third most common type of cancer, is the leading cause of cancer-related deaths worldwide. Though it can be fatal, early diagnosis and treatment can improve the outlook. However, survival rates depend on the type and stage of cancer.
Typically, survival rates are higher if treatment begins before cancer spreads outside the lungs. Current statistics suggest that the five-year survival rate of stage I lung cancer is anywhere from 70 to 92 percent, depending on the type.
Localized or stage I cancer is defined as cancer that is limited to the lungs or a lung lobe.
The estimated five-year survival rate for non-small cell lung cancer (NSCLC) is about 65 percent (stage I lung cancer) and for small cell lung cancer (SCLC) is 27 percent. The relative five-year survival rate for mesothelioma is 5 to 10 percent.
What are the different types of lung cancer?
There are two main types of lung cancer, namely, small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). They differ in their appearance and the way they grow and spread.
NSCLC
The most common type of lung cancer, accounting for about 80 to 85 percent of lung cancer cases. It usually grows and spreads more slowly than SCLC.
There are three main subtypes of NSCLC
- Adenocarcinoma: Begins in the cells that secrete mucus and is present in the outer parts of the lungs. It grows slower than the other two subtypes and, therefore, has a better chance for diagnosis and treatment before it spreads.
- Squamous cell carcinoma: Begins in the squamous cells that line the inside of the large breathing tubes. It is usually found in the central part of the lungs, near the main airway bronchus.
- Large cell carcinoma: Can begin in any part of the lung and tends to grow and spread quickly, making it harder to treat.
Other subtypes of NSCLC, such as adenosquamous carcinoma and sarcomatoid carcinoma, are less common.
SCLC
Less common than NSCLC, accounting for about 15 to 20 percent of all types of lung cancer, and usually occurs in heavy smokers. It tends to grow and spread faster than NSCLC. In about 70 percent of people with SCLC at the time of diagnosis, cancer is likely to have spread to other parts of the body.
Other rare types of lung cancer include
- Lung carcinoid tumors: Accounts for less than five percent of lung tumors.
- Mesotheliomas: Develop from the pleura, the protective membrane that covers the lungs, and is usually associated with asbestos exposure.
- Other lung tumors: Include rare tumors such as adenoid cystic carcinomas, lymphomas and sarcomas.
What are the stages of lung cancer?
Cancer is staged based on the tumor size, location and spread, as well as its severity. Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are staged in specific ways.
Stages of NSCLC
- Stage I: The tumor is about 3 cm or less and found in only one lung.
- Stage II: The tumor is 7 cm or less and might have spread to nearby tissues and lymph nodes.
- Stage III: Cancer may have spread to the lymph nodes at the center of the chest and reached other parts of the lung and surrounding area. Stage III has two subtypes:
- Stage IIIA: Cancer is on the same side of the chest where it started.
- Stage IIIB: Cancer has spread to the lymph nodes on the opposite side of the chest or near the collarbone.
- Stage IV: Cancer has spread to both the lungs, fluid around the lungs, distant lymph nodes and other organs.
Stages of SCLC
This type of lung cancer has two main stages:
- Limited stage: Cancer is found in only one lung or nearby lymph nodes on the same side of the chest.
- Extensive stage: Cancer has spread to the opposite lung, lymph nodes on the opposite side, fluid around the lungs, bone marrow and distant organs. Two-thirds of people with SCLC are diagnosed in the extensive stage.
What are the causes of lung cancer?
The exact cause of lung cancer is unknown, though it occurs when the cells in the lung mutate or change. Researchers believe that smoking or breathing hazardous substances cause changes or mutations in the lung cells. Over time, the damaged cells act abnormally and divide uncontrollably causing tumors to grow, which eventually develops cancer.
Risk factors
Various factors increase the risk of lung cancer, such as:
- Smoking: The leading cause of lung cancer, accounting for about 90 percent of cases.
- Exposure to secondhand smoke: Even if a person doesn’t smoke, their risk increases when exposed to secondhand smoke regularly.
- Gene mutations: Mutated genes make the cells incapable of fixing the damaged DNA.
- Radon exposure: Radon is produced by the breakdown of uranium found in soil and rocks and gives off radiation.
- Occupational exposure to carcinogens: Workplace exposure to asbestos, uranium, arsenic, beryllium, vinyl chloride, cadmium, silica, chromium compounds, nickel compounds, coal and coke fumes, mustard gas, chloromethyl ethers, petroleum products, gasoline and diesel exhaust can increase the risk of lung cancer.
- Family history of lung cancer
- Human immunodeficiency virus (HIV) infection
- Air pollution
- High levels of arsenic in drinking water
- Previous radiation therapy