It’s easy to think of lung cancer as a diagnosis with one possible outcome. The truth is, there are several types of lung cancer with key differences in what causes them. There are also differences in how each type of lung cancer develops in the body and how it is treated.
Most lung cancer diagnoses are divided into several types and subtypes. However, all lung cancer patients have unique experiences, even if they have the same disease.
This article will help you learn more about these types of lung cancer and how they vary based on age, sex, smoking status, and other factors.
Main types of lung cancer
Primary lung cancers are those that start in the lungs rather than spread (metastasize) to the lungs from other parts of the body.
There are two main types of primary lung cancer:
- Non-small cell lung cancer (NSCLC) is the most common type of lung cancer overall. It accounts for 80% to 85% of lung cancers in the United States.
- Small cell lung cancer (SCLC) is diagnosed in 10% to 15% of lung cancer cases.
The third type is called carcinoid tumor Less common in the lungs. It accounts for only 1 to 2 percent of lung cancers.
NSCLC and SCLC are also divided into specific subtypes. These names are based on the types of cells that make up the tumor as seen under the microscope.
non-small cell lung cancer
Non-small cell lung cancer usually grows and spreads more slowly than small cell lung cancer. Both are associated with smoking, but NSCLC is also the most common type of lung cancer in young adults and never-smokers.
Risks and causes may depend on the subtype of NSCLC diagnosed. There are three main subtypes:
- Lung adenocarcinoma It accounts for 40% to 50% of NSCLC cases.
- squamous cell carcinoma Occurs in approximately 30% of NSCLC cases.
- Large cell lung cancer accounts for approximately 10% of all NSCLC cases.
Small Cell Lung Cancer
Small cell lung cancer is usually an aggressive, fast-growing cancer.
It is closely related to smoking, although other factors, including radon exposure, may be involved. (Radon is a colorless, odorless gas that seeps into the house from the surrounding soil.)
The two subtypes of SCLC are:
- small cell carcinoma
- Combined small cell carcinoma (cells mixed with another type)
How is cancer different from other cancers?
The two main types of lung cancer are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). NSCLC is the most common type, with three main subtypes.
NSCLC is a common lung cancer diagnosis in both men and women. However, one study described lung adenocarcinoma as a “different disease in women and men.”
In women, lung adenocarcinoma accounts for 40% to 60% of lung cancer cases.About half of these cancers are no associated with smoking, which is only 10% to 15% in non-smoking men.
Women also tend to be younger at diagnosis and respond differently to treatment.
Men with non-small cell lung cancer are more likely to develop squamous cell lung cancer, which is linked to smoking. Compared with women, they were slightly less likely to be diagnosed with small cell lung cancer.
SCLC is also more common among white men than black men, although black men are about 15% more likely to be diagnosed with lung cancer overall.
How does lung cancer differ in men?
Differences based on age
Like many diseases, lung cancer is often more common in older adults. However, lung cancer can occur at any age.
Lung adenocarcinoma is the most common type of lung cancer in young adults. It accounts for about 80% of cases, and SCLC is relatively rare in this group.
Young people with lung cancer are more likely to have a genetic predisposition to lung cancer. For this reason, they may have genetic changes that can be treated with new therapies targeting specific mutations.
Lung carcinoids are more likely to be found in young adults than the two main types of lung cancer. These are the most common types of lung tumors in children.
smokers vs non-smokers
In many ways, lung cancer in non-smokers is very different from lung cancer in smokers. This applies even to the most common types of diseases.
Both NSCLC and SCLC were associated with smoking history, although the association was much stronger for SCLC.
Of the three types of NSCLC, lung adenocarcinoma is the type most likely to be found in non-smokers. Squamous cell carcinoma is generally less common than lung adenocarcinoma, but is more common in smokers and ex-smokers.
Carcinoid tumors do not appear to be associated with smoking. They were found in smokers and non-smokers in numbers similar to those in the general population.
Current and former smokers are more likely than others to develop SCLC and the squamous cell subtype of NSCLC. The lung adenocarcinoma subtype of NSCLC is more common in women, younger people, and people who have never smoked.
What percentage of smokers get lung cancer?
The role of ratios and genetics
The incidence of lung cancer has changed over time. Partly because of the health effects, people start to quit or avoid smoking.
One of the biggest questions, however, is why lung cancer rates are rising among young people and people who have never smoked.
Environmental factors such as air pollution may be partly to blame, but that doesn’t explain much. Research led by the National Cancer Institute and the National Institutes of Health points to genetics.
Their September 2021 study looked at genetic changes in 232 non-small cell lung cancer patients who had never smoked and compared their normal tissue to tumor samples.
In the study group, 189 people had lung adenocarcinoma and the rest were other types. Genetic mutations from natural processes in the body have been linked to lung cancer, the study found.
The researchers also report three new genetic subtypes of lung cancer in these never-smokers.
While they caution that more research is needed, the findings point to the possibility of future therapeutic targets.
Targeted mutations in lung cancer
Science continues to delve into genetic links to lung and other cancers. Still, many health care providers and cancer specialists (oncologists) recommend genetic testing for cancer patients.
This is especially true for patients with non-small cell lung cancer. Targeted therapies are available or are being developed for people with specific cancer-related changes (mutations) in their genes, including:
- epidermal growth factor receptor
Tumors with treatable mutations are more common in young adults, never-smokers, and women. However, many lung cancer patients may benefit from targeted therapy.
Smoking is the leading cause of lung cancer, but not the only one. Genetics may play a key role, especially among young people, women and people who have never smoked. Genetic testing may be recommended to see if you have a mutation for which treatment is available.
What is targeted therapy for lung cancer?
There are many types and subtypes of lung cancer, most of which are forms of non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC). There are differences between these types.
Perhaps the most important one is that smoking remains the leading cause of some lung cancers and is associated with NSCLC and SCLC types, but many other lung cancers are diagnosed in people who have never smoked.
Radon and other environmental causes can cause these cancers. In some cases, especially in young adults, there may be an underlying genetic cause.
Non-small cell lung cancer tends to grow more slowly and has a better prognosis than small cell lung cancer. That said, finding any form of lung cancer in the early stages of the disease has better long-term survival rates.
Lung cancer screening is recommended for people who are 50 to 80 years old, have a smoking history of at least 20 pack years, and have smoked or quit smoking within the past 15 years. If you’ve never smoked, you may still want to ask questions about screening.
A 2019 study Journal of Thoracic Oncology Low-dose computed tomography (CT) imaging has been found to help detect early-stage cancers that would otherwise be missed.