A Review of How Asthma May Cause Lung Cancer

Multiple studies show that asthma could be a significant risk factor for lung cancer in smokers and non-smokers alike, with lung cancer being approximately 40 percent more common in asthmatics who need treatment. The risk varies with lung cancer types, and the probability seems to be lower with lung adenocarcinoma, which is a prevalent form of lung cancer that most often arises in non-smokers, young adults, and women. Research about the underlying biology is in early stages, yet it is already apparent that controlling asthma may reduce the risk of lung cancer development.

Studies About the Link Between Asthma and Lung Cancer

Several studies have delved into the riveting relationship between asthma and lung cancer in the past, although most of the results were inconclusive. Recent reviews of these studies, however, are beginning to uncover the truth.

According to the results of a meta-analysis of studies from 2017, asthmatics had a 44 percent susceptibility to developing lung cancer. This information proved accurate for both men and women, Caucasians and Asians, as well as smokers and non-smokers. Yet the risk was not evident with lung adenocarcinoma.

A 2019 study also examined the connection of cancer to asthma and allergies. The researchers affirmed a correlation between tobacco smoking and lung cancer, with asthma associated with a 25 percent increased risk of lung cancer. A link between asthma and other cancers, such as malignancies in the breast or prostate, was nonexistent. In contrast, people with allergies had a 20 percent reduced risk of lung cancer, and there was no recorded link between allergies and cancers of the breast or prostate.

Some scientific studies have found a greater link among non-smokers with lung cancer. A large study (1.2 million women) from the United Kingdom revealed that non-smokers who had severe asthma had a 32 percent chance of developing lung cancer.

Asthma and the Different Types of Lung Cancer 

As mentioned, a large meta-analysis of studies did not find a connection between asthma and lung adenocarcinoma. This piece of information surprised many, particularly since asthma may be a significant risk factor among non-smokers, and because lung adenocarcinoma is the most common type of lung cancer that occurs in individuals who do not use tobacco products.

In addition, a systematic investigation by the International Lung Cancer Consortium further elaborated on the link between asthma and lung cancer by breaking down the cancer types. The investigators found the strongest connections between asthma and oat cell carcinoma of the lung cancer (71 percent increase), squamous cell carcinoma of the lung (69 percent increase), and lung adenocarcinoma (9 percent increased risk).

The Common Risk Factors

Another explanation for the potential link between asthma and lung cancers is common risk factors. Most of us are well aware that smoking and exposure to secondhand smoke are risk factors for both asthma and cancers of the lung (among many others). And yet, the majority of studies that assessed the correlation between asthma and lung cancer “control” for smoking. In other words, they looked for a way to exclude smoking as the link, so that they could find other factors (these are called “controlled studies”). Although the researchers conducted controlled studies, the risk of lung carcinoma associated with asthma still remains.

How Asthma May Cause Lung Cancer

One theory is that the long-term inflammation in the lungs due to asthma is the supposed cause of lung cancer. Recently, scientists evaluated long-term inflammation as a potential cause of many cancers. A multitude of studies suggest that chronic lung inflammation due to asthma may be a “co-factor” in lung cancer development, which means that asthma, integrated with other causes, may work together to cause lung malignancies. Among these “other” factors may include a genetic condition, and cancer researchers are learning that many hereditary factors appear to play a role in lung cancer among non-smokers.

Researchers are uncovering the fact that cancer is more than an errant clone of cells growing alone. Instead, cancer cells interact closely with neighboring tissues, which is an area called “tumor microenvironment.”

With asthma, a form of connective tissue cells called bronchial fibroblasts are important. Inside a lab, researchers examine lung cancer cells and the signals human bronchial fibroblasts secrete from people with and without asthma. A 2018 study found that the lung cancer cells exposed to signals from the fibroblasts of asthmatics were more motile. It is not clear whether this study interprets exactly what happens in the human body and if it would only impact lung cancer cells already present. The breakthrough study, however, succeeded to show how analyzing the underlying biological processes in place might better explain the possible link between asthma and lung cancer in the future.

How to Minimize Lung Cancer Risk for People With Asthma

A nationwide study comprising over 37,000 people with asthma suggests that controlling the inflammation associated with asthma may help lower lung cancer risks. The researchers found that male and female asthmatics who used inhaled corticosteroids on a regular basis had, on average, a 58 percent reduced chance of developing lung cancer.

Of course, this potential health benefit of inhaled corticosteroids requires further investigation. Scientists must weigh the advantages against the side effects of steroid inhalers, which include oral thrush, nosebleeds, voice hoarseness, and others. However, whether managing your asthma makes a difference or not, keep in mind that it is one concern. Even if these inhalers do not make an immense difference with regard to your lung cancer risk, having asthma attacks under control will be a boost in your overall quality of life.

If you have asthma, there are several preventive methods you can do to lower your lung cancer risk, including:

  • Do not smoke cigarettes or use tobacco products
  • Avoid exposure to secondhand smoke
  • Check your home for radon
  • Be cautious of the chemicals you might be exposed to at work
  • Wear a mask if you live in an area with severe air pollution
  • Undergo CT lung cancer screening if you have risk factors

The Bottom Line

People with asthma who have never smoked have a higher risk of getting lung cancer than the general population, according to these studies. Those who smoke have an even higher risk, so if you still huff and puff, now is the time to try strategies for quitting smoking

What to Do If Your Doctor Diagnosed You With Lung Cancer

Choosing the right treatment provider is one of the most important decisions you can make as a lung cancer patient. Here at New Hope Unlimited, you will receive personalized treatments from leading experts in conventional and alternative lung cancer therapies. Are you ready to discover a new world of treatment options for your disease? Call us today at 480-666-1403 to schedule your consultation.

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