About 25 million Americans have asthma, a chronic inflammatory disease of the airways that makes the inner lining of your lungs swell. Between 5% and 10% of Americans with the disease have severe asthma. Severe asthma is categorized by needing medium- to high-dose corticosteroids and other long-acting drugs. Often, these drugs won’t control asthma symptoms, which people with asthma have every night and most days of the week.
The inflammation that is caused by asthma triggers attacks when patients breathe in allergens like pollen, dust, or pollutants.
Lung cancer is also driven by inflammation in the respiratory tract, which can contribute to the development of tumors.
“Inflammation does appear to be linked to malignancies,” said William L. Dahut, MD, chief scientific officer of the American Cancer Society. “Inflammation from asthma may be one of the reasons why people with asthma are more likely to have lung cancer.”
“In a basic lab study, the investigators found invasive bronchial fibroblasts derived from asthmatic patients can activate lung cancer cells,” said Yi Guo, PhD, an associate professor of health outcomes and biomedical informatics at the University of Florida College of Medicine in Gainesville. “More studies are needed to explore this relationship in real-world patient populations.” (Guo has also co-authored a new study that found patients with asthma are almost one-and-a-half times more likely to get cancer than those in good respiratory health.)
Researchers in the United Arab Emirates have found that severe asthma patients are often diagnosed with lung cancer after it has developed over 3 decades. This is important because it shows that inflammation from severe asthma may contribute to long-term low-level damage to lung tissue. Authors of the study working with Canadian researchers further found that severe asthma patients are more likely to be diagnosed with aggressive stage III or IV lung cancer, and that doctors may want to consider severe asthma as a predictor of risk for the disease.
Read on for a look at the things that could put people with severe asthma at a higher risk for lung cancer, as well as how to reduce those chances.
What Are the Symptoms of Severe Asthma?
- Shortness of breath
- Tightness in your chest
People with severe asthma may also breathe rapidly, have changes in their heart rate, and can strain their head and neck muscles from the stress of coughing or trying to get more air.
What Are the Symptoms of Lung Cancer?
There are two types of lung cancer. Adenocarcinoma occurs in up to 85% of patients and is also related to a subtype called squamous cell lung cancer. Small-cell lung cancer, which occurs in only 15% of patients, grows and spreads faster. For severe asthma patients, “the increased lung cancer risk does not occur in adenocarcinoma, but is more common in small cell and in squamous cell,” Dahut said.
Lung cancer symptoms include:
- A worsening or persistent cough
- Chest pain
- Shortness of breath
- Coughing up blood
- Extreme fatigue
- Unexplained weight loss
Some of the symptoms of lung cancer overlap with signs of severe asthma. It’s important that people with severe asthma tell their doctor about anything new that's concerning.
Should You Be Screened for Lung Cancer if You Have Severe Asthma?
At this, time, the recommendations for lung cancer screening apply to patients who:
- Have a 20 pack-year or more smoking history, and
- Smoke now, or quit within the past 15 years, and
- Are between the ages of 50 and 80
That said, risk can be very specific, so it's important for people to do what's right for them on an individual level.
“It’s important to abide by what your doctor recommends,” said Albert Rizzo, MD, chief medical officer for the American Lung Association. “If you have a family history of lung cancer, it’s also important to review that with your doctor.”
How Can You Lower Your Lung Cancer Risk if You Have Severe Asthma?
To reduce the risk, it's important to:
- Keep on top of your symptoms. Researchers in Norway recently found that patients with only partially controlled lung cancer symptoms have a higher risk of lung cancer. If your asthma symptoms are controlled well, there’s much less chance of damage to your lung tissue.
- Ask about adjusting your medication.
“Some studies have also shown that patients who used inhaled glucocorticoids decrease the risk of lung cancer,” said Dahut. (Glucocorticoids not only fight inflammation in severe asthma, but also in cancer.)
- Don’t smoke, and avoid all secondhand smoke.
- Make your living space safer.
“Get your home tested for radon gas, which can raise your risk for lung cancer,” Rizzo said.
- Avoid cancer-causing chemicals where you work. Diesel fumes, for example, have been linked to a higher lung cancer risk. Avoid exposure to them as you commute as well by rolling up your windows in traffic.
- Eat more fruits and veggies. These foods contain powerful compounds that can have a protective effect. Broccoli, cauliflower, cabbage, bok choy, and Brussels sprouts contain sulforaphane, which can cut cancer risk. Leafy greens are packed with folate, which also can help prevent the disease. Plus, think orange: Foods of that color, such as oranges, tangerines, peaches, papayas, red bell peppers, and carrots, contain beta-cryptoxanthin, a pigment that’s a known cancer fighter.
- Exercise as much as you can. Ask your doctor to recommend low-impact workouts that won’t cause breathlessness.
“The more control you have over your risk factors for lung cancer, the more your odds may decrease,” Rizzo said. In short: There’s a lot you can start doing today to live a longer, healthier life.