Another Blow for Asthma Sufferers
May 10, 2000 (Toronto) -- If you have asthma and smoke, you have another
reason to stop. People with asthma who have never smoked have a higher
risk of getting lung cancer than the general population, and those who also
smoke have an even higher risk, according to a review of research presented
here at a meeting of the American Thoracic Society.
This finding should not cause panic among asthma patients, though, lead
researcher Alfredo A. Santillan, MD, tells WebMD. "Asthma is a risk factor
for lung cancer. [H]owever, only a small fraction of asthmatics are prone to
develop lung cancer because of asthma," says Santillan, noting that the
increased risk, almost two times above the general population, is still
relatively low. "Those who are current smokers probably are at higher risk
and should avoid cigarette smoking."
Asthma patients who were former smokers were more than two times more likely
to get the disease. Santillan is a research physician in the medical school at
the Institute of Advanced Studies in Monterrey, Mexico.
Prior research has identified links between other types of noncancerous lung
disease, such as emphysema and chronic bronchitis. Because the association
between asthma and the risk of lung cancer has not been proven, Santillan and
co-authors at Massachusetts General Hospital in Boston reviewed the studies
completed up to this point to see if they could reach a conclusion.
And reach a conclusion they did, Santillan tells WebMD. He says that even
when the analysis was limited to people who had never smoked, the data
suggested a direct relation between asthma and lung cancer.
Investigators have yet to determine why asthma would make individuals more
susceptible to lung cancer. The most likely explanation, Santillan says, may be
the way that several facets of asthma interact with the environment. These
include impaired lung function, chronic inflammation of the airways, and
alterations in the immune system, which fights off disease. Therefore, they may
be more vulnerable to cancer-causing agents, found in second-hand smoke, the
by-products of heating and cooking, and air pollution, and substances such as
asbestos and arsenic that could be encountered in certain jobs.
"[T]he most important [finding] derived from this study is that
asthmatics should avoid smoking cigarettes," Santillan tells WebMD.
"Despite the ? impairment observed in asthma, asthmatics still continue to
smoke," at a rate of approximately 20% to 60%. Therefore, the risk of lung
cancer among asthma patients is high because of asthma, because of smoking, and
because of both factors combined, he says.
- Compared to the general public, people with asthma who have never smoked
have a slightly increased chance of developing lung cancer. Asthmatic smokers
face a larger risk of lung cancer, according to researchers.
- The study's lead researcher says the finding should not cause panic in
people with asthma, but smokers should quit their habit.
- Previous studies have shown other lung diseases like emphysema and chronic
bronchitis can raise lung cancer risk. The researchers aren't sure why asthma
seems to fit this list, too, but they speculate environmental factors could be