Cancer Conundrum Why are more nonsmoking women being diagnosed with lung cancer?

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Cancer Conundrum lung cancer
Art by Daria Krasnova/Getty Images

The image of a woman hearing the word “cancer” delivered solemnly across her doctor’s desk brings to mind diagnoses of breast, skin or ovarian categories. Lung cancer is not as expected, but it has become increasingly common.

Approximately 229,000 adults will be diagnosed with lung cancer this year (13% of all new cancer diagnoses), according to American Cancer Society estimates. People tend to think of lung cancer as a disease of men who have smoked for years. More and more, however, doctors are diagnosing lung cancer in nonsmoking women. Dr. Josephine Feliciano, associate professor of oncology, clinical director, Johns Hopkins Sidney Kimmel Cancer Center at Bayview, Center of Excellence in Thoracic Oncology, has studied this development.

Trending Upward

Feliciano says the medical community first took notice of the increase around the early 2000s, even as cigarette use in general decreased. “It was becoming recognized that there were patient populations with little or no tobacco exposure being diagnosed with metastatic lung cancer.”

But is the same lung cancer affecting both smokers and nonsmokers? “In general, this appears to be a very different type of lung cancer than smokers get, but there is no mutually exclusive category,” says Feliciano. “In nonsmokers, it is more common to have a molecular variant or subtype of lung cancer that can respond to treatments given as pills as opposed to IV therapies such as chemotherapy or immunotherapy.

Additionally, these types of lung cancers in nonsmokers may not respond to therapies that smokers may be more likely to respond to, such as immunotherapy. The lung cancers in nonsmokers are often of the adenocarcinoma subtype. Patients with significant smoking history are also prone to squamous cell carcinoma and small cell carcinoma.”

Women at Risk

According to the American Cancer Society, up to 20% of people who die from lung cancer each year have never smoked. That’s enough deaths to categorize lung cancer in nonsmokers among the top 10 deadliest cancers in the United States. What’s more, the National Institutes of Health found that women are decidedly more at risk than men. For nonsmokers between the ages of 40 and 79, the incidence of lung cancer among men is between 5% to 14%. In women, this percentage ranges between 14% to 21%.

“Hormones may also contribute, and there is research looking at hormones in lung cancer, not only specifically in nonsmokers, but also in smokers,” says Feliciano. Among the differences between the sexes, however, “in general, women tend to live longer and have better survivals from lung cancer than men, stage for stage.”

Nonsmoking Causes of Lung Cancer

Researchers continually seek clues to explain the increase. “There is not clear-cut data that there is one prevalent risk factor to develop lung cancer if you are a nonsmoker,” notes Feliciano. “Some factors include environmental pollution, indoor pollution, radon and asbestos. There are also some genetically related risk factors such as having a family member with lung cancer, or having an inheritable type of lung cancer or cancer syndrome.”

The U.S. Environmental Protection Agency identifies exposure to radon as a significant cause of lung cancer, accounting for approximately 21,000 deaths per year, including close to 2,900 nonsmokers. Extended exposure to concentrated radon contamination puts people at greater lung cancer risk, but the only way to know if radon is a problem in your home is to test for it, as radon cannot be smelled or seen.

Bans on public smoking have been effective in reducing the danger of secondhand smoke in the last two decades. Nonetheless, about 7,000 people die each year because of lung cancer caused by secondhand smoke, according to the American Cancer Society. Industry regulations have made workplaces safer with better control of exposure to carcinogens such as asbestos and diesel exhaust. Thankfully, air pollution in the United States is not as bad as in other countries. Improvements have been made, yet incidence continues.

Early Detection Saves Lives

As with other cancers, early detection is key. Distant metastatic lung cancer has a five-year survival rate of 6%. Each year, tens of thousands of patients are cured of non-small-cell lung carcinoma
(NSCLC). In addition, any stage of lung cancer is treatable in some way.

“The curability and survivability of lung cancer correlates with the stage at which it is diagnosed,” says Feliciano. Screening, done by a low-dose CT scan, is only used for high-risk populations. “Unfortunately, for nonsmokers, there is no proven lung cancer screening modality as there is for patients who have significant smoking histories. Also, lung cancer in general tends to present with symptoms when the disease is more advanced when it is not detected by screening.”

What are potential warning signs? “Symptoms of lung cancer may be a cough, shortness of breath or chest pain,” Feliciano explains. “As the cancer becomes more advanced, people may feel more tired, have poor appetite or weight loss, or have symptoms if the cancer spreads to another organ, such as pain if it goes to a bone or headaches or seizures if it goes to the brain. One challenge is that the symptoms are not specific to lung cancer, and many patients may assume symptoms are related to another health condition such as pneumonia, asthma or heart disease.”

Be aware of any persistent or worsening symptoms, and don’t hesitate to contact your doctor with concerns. The American Lung Association reports that about 142,000 lung cancer deaths occurred in 2019—more deaths than from colon, breast and prostate cancers combined.

Advances in Cancer Treatment

Still, treatments are progressing in exciting ways. “There have been more treatments for lung cancer approved in the last 10 years than in the last 30 years combined,” says Feliciano. “The majority of these improvements have been in the metastatic and locally advanced stages of lung cancer. Targeted therapies and immunotherapy have been responsible for improving lung cancer survival in the last 10 years.”

Unique, molecularly driven subsets of lung cancers may respond well to targeted medications. “There are many types of ‘targetable’ lung cancer with approved therapies and more in the pipeline,” says Feliciano. “Immunotherapy has also improved the survival for lung cancer, particularly in the metastatic and locally advanced setting.”

Approaches to treatments have changed over time. Drugs such as gefitinib and erlotinib were initially approved for lung cancer patients regardless of smoking status, but doctors began to see that some populations responded unusually well—nonsmokers and Asian women, in particular, had the best response. “Since that time, many more unique variants have been identified, and many more drugs have been developed, many of which are more common in patients with minimal or no smoking history,” says Feliciano.

No one is fully exempt from risk, but healthy practices are still worthwhile. Don’t smoke. Eat a diet rich in fruits and vegetables. Stay on top of your own well-being. Listen to your body. Successful identification and treatment of any cancer begins with acute attention to changes occurring in your body. Breathe in awareness.

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