Lung cancer is the second most common cancer and the leading cause of cancer-related death worldwide.
There are two main types of lung cancer: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). These types differ in their prevalence, treatment, and outlook.
This article outlines the prevalence of NSCLC compared with other lung cancers and over time. It also lists the risk factors associated with NSCLC and provides statistics on survival rates for the condition.
There are three main subtypes of NSCLC:
- Adenocarcinoma: This is the most common type of primary lung cancer, accounting for
around 40%of all lung cancer cases. It is the leading cause of cancer death in the U.S., and it is the most common lung cancer among people who have never smoked.
- Squamous cell carcinoma (SCC): This is the second most common type of NSCLC, accounting for
about 25%of all lung cancer cases. This subtype is associated with smoking, and it is more common among women.
- Large cell carcinoma (LCC): This type accounts for
approximately 10%of all lung cancer cases. This subtype can appear on any part of the lung and tends to grow and spread rapidly.
Below are some of the risk factors associated with NSCLC.
Although the average age for NSCLC diagnosis is 70 years old, one
Some factors associated with NSCLC cases in younger people include:
- being female
- being Asian or Pacific Islander
- having adenocarcinoma
Compared with males, females appear to have an increased risk of NSCLC complications. According to a
Black men have a
According to the Centers for Disease Control and Prevention (CDC), people who smoke are
The CDC also notes that around 80–90% of deaths from lung cancer are linked to smoking. This risk increases with the number of years a person smokes and the number of cigarettes they smoke each day.
Exposure to secondhand smoke
Most people with lung cancer who do not smoke develop NSCLC as opposed to SCLC. The most common NSCLC subtype among people who do not smoke is adenocarcinoma.
A 2017 study of people in Korea with NSCLC found that
Exposure to secondhand smoke accounts for
Exposure to toxic substances
Exposure to the following substances increases the risk of lung cancer:
- heavy metals, such as arsenic and chromium
Radon exposure is the leading cause of lung cancer among people who do not smoke. However, exposure is associated with an increased risk of SCLC rather than NSCLC.
The 5-year survival rate refers to the percentage of people who live 5 years or more following their initial cancer diagnosis. According to
Five-year survival rates vary according to lung cancer stage, which is the extent to which the cancer has spread. The three stages and their associated survival rates are as follows:
- Localized disease: This is cancer that has not spread outside the lungs. The 5-year survival rate for NSCLC at this stage is 64%.
- Regional disease: This is cancer that has spread to nearby areas outside the lung. The 5-year survival rate for NSCLC at this stage is 37%.
- Distant disease: This is cancer that has spread to distant areas. The 5-year survival rate for NSCLC at this stage is 8%.
According to a 2020 review, the following factors have significantly improved treatment outcomes and survival rates among people with NSCLC:
- earlier diagnosis
- a more accurate and detailed classification system for lung cancers
- advances in treatment
The number of new lung cancer cases continues to
However, at the time of this article’s publication, there is a decline in cases of SCC and a continuous rise in cases of adenocarcinoma.
The decline in SCC is likely due to increases in the number of people giving up smoking or choosing never to begin smoking. The cause of the rise in adenocarcinoma is currently under investigation.
The ACS predicts that
Generally, lung cancer incidence and mortality rates are slowly declining. However, the pace of decline is faster among males than among females, and it started at least a decade earlier for men than women.
Quitting smoking plays an important role in lung cancer outlook. A 2020 study suggests that quitting smoking anytime can reduce a person’s risk of dying from lung cancer.
The greater the elapsed time between quitting smoking and lung cancer diagnosis, the greater the odds of survival, as outlined below:
- Quitting fewer than 2 years before diagnosis: This is associated with a 12% reduced risk of mortality.
- Quitting 2–5 years before diagnosis: This is associated with a 17% reduced risk of mortality.
- Quitting more than 5 years before diagnosis: This is associated with a 20% reduced risk of mortality.
NSCLC is the most common type of lung cancer. It has three subtypes: adenocarcinoma, SCC, and LCC.
The incidence of NSCLC has changed over time. Subtypes associated with smoking are declining as more people are giving up smoking or choosing never to smoke in the first place.
Survival rates for NSCLC are improving, thanks to earlier diagnoses, more accurate and detailed disease classification, and advances in lung cancer treatment.