Some other things increase lung cancer risk. But they increase the risk by only a small amount and far less than smoking. They are
- Exposure to radon gas
- Exposure to certain chemicals
- Air pollution
- Previous lung disease
- A family history of lung cancer
- Past cancer treatment
- Previous smoking related cancers
- Lowered immunity
Exposure to radon gas
Radon gas is a naturally occurring radioactive gas which comes from tiny amounts of uranium present in all rocks and soils. The radon gas can build up in homes and other buildings. The highest levels have been found in south west England, but higher than average levels may be found in many other parts of the UK.
Radon is one of the biggest causes of lung cancer after smoking. The risk from radon increases the risk from smoking. Smokers with high indoor levels of radon have a particularly high risk of getting lung cancer. So if you live in a high radon area, it’s even more important to stop smoking.
Exposure to certain chemicals
A number of substances that occur in the workplace may cause lung cancer. In particular, these include asbestos, silica, and diesel exhaust. Exposure to asbestos in the construction industry and shipbuilding is now much lower than in the 1960s. But asbestos is still a cause of lung cancer because cancers take so long to develop. And smokers are at even higher risk.
Silica which is used in glass making, may cause a condition known as silicosis. This condition increases the risk of lung cancer.
People at the highest risk of lung cancer caused by diesel fumes are miners and professional drivers.
We know that air pollution can cause lung cancer. The risk depends on the levels of air pollution you are regularly exposed to.
Previous lung disease
Having had a disease that caused scarring in the lungs may be a risk factor for a type of lung cancer called adenocarcinoma of the lung. Tuberculosis (TB) can make scar tissue form in the lungs. People who have had TB have double the risk of lung cancer. This risk continues for more than 20 years.
Chlamydia pneumoniae is a type of bacteria that can cause chest infections. Some studies have shown that people with antibodies to chlamydia pneumoniae have an increased risk of lung cancer. The risk is greater for people who smoke.
A family history of lung cancer
Researchers are looking into the impact of family history on lung cancer. The risk is even greater if a brother or sister has lung cancer, rather than a parent. This risk is regardless of whether or not you smoke. But families of smokers might be exposed to cigarette smoke and so have an increased risk of lung cancer whether they have inherited a faulty gene or not.
Because there is a pattern of increased risk of lung cancer in family members, researchers think it is likely that there is at least one faulty gene that can increase the risk of lung cancer and be passed down in families (inherited). Research trials are trying to find such a gene.
Past cancer treatment
There is some evidence that particular cancer treatments might increase your risk of lung cancer. A review of lung cancer after treatment for breast cancer shows that ways of giving radiotherapy for breast cancer in the past increased the risk of developing lung cancer. But the most up to date methods of giving radiotherapy to treat breast cancer do not seem to increase the risk of primary lung cancer.
Recent research shows that women who have estrogen receptor negative breast cancer may be at increased risk of developing lung cancer.
Treatment for other types of cancer has also been linked to a slightly increased risk of lung cancer some years later. People may have an increased risk of lung cancer if they have had treatment for
- Hodgkin lymphoma
- Some types of non Hodgkin lymphoma
- Testicular cancer
- A type of cancer of the womb
But it is important to remember that having no treatment for these cancers is a much greater risk to your health than the slight increase in risk from treatment. It is most important to get the treatment you need at the time. In some of this research, lung cancer risk seems to be increased even more in smokers, so if you have had radiotherapy to your chest it is very important not to smoke.
Previous smoking related cancers
People who have had a head and neck cancer, esophageal cancer or cervical cancer have an increased risk of lung cancer. This may be explained by the fact that the risk of these cancers is higher in smokers. But it could also be a result of radiotherapy treatment.
HIV and AIDS lower immunity and so do drugs that people take after organ transplants. An overview of research studies shows that people with HIV or AIDS have a risk of lung cancer that is 3 times higher than people who do not have HIV or AIDS. People who take drugs to suppress their immunity after an organ transplant have double the usual risk of lung cancer.
There is also in increased risk of lung cancer in people who have some autoimmune conditions. For example research shows that people with lupus (systemic lupus erythematosus or SLE) may have 2 to 3 times the average risk of lung cancer. People with rheumatoid arthritis may also have an increased lung cancer risk.