One common response to learning that an acquaintance has been diagnosed with lung cancer might be, “I didn’t know he smoked, or used to smoke.”
But the truth is that many cases of lung cancer are not related to tobacco. In fact, about 10% to 20% of Americans diagnosed with lung cancer have never smoked, according to the Centers for Disease Control and Prevention (CDC). “Never smokers” are individuals who have never smoked, or who have smoked less than 100 cigarettes during their life, according to the CDC.
While the rate of lung cancer diagnoses and death are declining — thanks to a decrease in the number of people who smoke and advances in screening and treatment –— the percentage of lung cancer cases among “never smokers” are rising accordingly. In fact, some studies say that not only is the proportion of lung cancer cases and never smokers rising, the actual number of cases also may be rising.
“The total incidence of lung cancer has declined significantly over the last few decades, in part because we now have 10% to 15% of the population smoking, as opposed to roughly half the adult population in the 1960s,” said Ian Horkheimer, MD, a board-certified medical oncologist and hematologist who practices in the Little Silver office of Regional Cancer Care Associates LLC, one of the nation’s largest networks of cancer specialists.
Beyond the statistics, Dr. Horkheimer said, lung cancer in never smokers is a significant concern: Up to 20% of people who die from lung cancer never smoked.
Lung Cancer Risk Factors in Never Smokers
The reason nonsmokers develop long cancer has yet to be determined. However, there are several risk factors that everyone should be aware of, including:
- Radon. While a small amount of radon outside is harmless, if it leaks above ground or accumulates in a home or other buildings, it can damage lungs. An odorless radioactive gas created by the breakdown of uranium, radon is found in soil, rocks and groundwater and is the second-most common cause of lung cancer, after smoking. It causes approximately 20,000 cases of lung cancer each year, according to the Environmental Protection Agency.
- Secondhand smoke. Secondhand smoke increases the risk of lung cancer by 20% to 35%, according to the CDC. The more prolonged or intense an individual’s exposure, the higher the risk. According to the CDC, secondhand smoke kills more than 7,300 nonsmokers in the United States every year.
- Chemicals. Extended exposure to arsenic, asbestos, chromium and other toxic chemicals has been linked to lung cancer. Those who work in settings in which they are exposed to these cancer-causing agents, as well as industrial chemicals such as paints, solvents, tinners, diesel exhaust and fumes generated by coal or wood cooking, are at an increased risk. Also posing a threat is arsenic, which occurs naturally in rocks and soil, and can contaminate drinking water that comes from private wells.
- Radiation. Individuals who undergo high-intensity radiation have an increased risk of lung cancer.
- Air pollution. High ozone levels and particle pollution due to extreme heat and wildfires are contributing to unhealthy air, according to a 2021 report from the American Lung Association. Fine particulate matter has been linked to lung cancer.
- A gene mutation. Some individuals who do not smoke, but are diagnosed with lung cancer, may have a damaged gene. One common abnormality, or mutation, happens in the epidermal growth factor receptor (EGFR) gene.
Another area of concern is family history, and some studies indicate that the human papillomavirus (HPV) may be a risk factor, but other studies have been unable to find a link. However, both potential risk factors need further study to see if there is a connection.
Dr. Horkheimer said he is particularly concerned about vaping and electronic cigarettes, which deliver concentrated nicotine and other carcinogens to varying degrees.
“Vaping is a relatively young habit within the last decade or so, so we really haven’t seen the ramifications,” he said. “I’ll be surprised if there is not an increased incidence of cancer in e-cigarette users, but time will tell. We won’t know the real cancer risk for another 20 or 30 years for youngsters who started out vaping instead of smoking cigarettes. And then there are the older folks who for some reason thought they would quit smoking and go on to vaping. The effect on them will be difficult to tease out.”
Another risk factor is sex. Dr. Horkheimer noted that lung cancer is more common in female nonsmokers than in male nonsmokers, adding that male nonsmokers are more likely to die of the disease.
Lung Cancer Symptoms
While nonsmokers have the same symptoms as those who do smoke, nonsmokers are more likely to dismiss them, chalking them up to something else rather than seeking medical attention, giving the disease more time to spread.
“Someone who otherwise feels absolutely fine might ignore a little cough, thinking it may be something like allergies. They may not see their doctor about it as soon as they should,” said James Lee, MD, a board-certified oncologist in RCCA’s Moorestown office.
Dr. Horkheimer agreed. “I tell people that if they have a symptom that comes and then goes away, cancer doesn’t do that. If you have a new symptom and it comes and doesn’t go away, and continues to get worse, seek medical attention sooner rather than later. If you have a problem for a couple of weeks, it needs to be evaluated,” he said.
Individuals should see a doctor if they persistently experience any of the following symptoms:
- Chronic cough
- Shortness of breath
- Excessive or bloody phlegm coughed up from the lungs
- Chest pain or discomfort
- Unexplained back pain
- Unexplained weight loss
- Loss of appetite
- Frequent chest infections
Types of Lung Cancer
Those with lung cancer are diagnosed with one of two forms: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The two types develop differently. Most nonsmokers, light smokers and former smokers develop a subtype of NSCLC called adenocarcinoma.
Because of biological differences between some tumors in nonsmokers and current or former smokers, many experts believe that some non-small cell lung cancers in never smokers could represent a different disease than NSCLC in smokers. That’s because tobacco damages the DNA in smokers’ cells, while a genetic mutation is responsible for the damage to the cells of many never smokers.
Age also may be a factor. A 2019 review of data from previously published studies found that, relative to current or former smokers, never smokers who developed lung cancer are younger, have more favorable outcomes and respond better to treatment.
Lung cancer treatments for never smokers and smokers are the same, and include one or one or more of the following:
- Surgery. In early stages of lung cancer, the tumor, surrounding tissue, a portion of the lung or the entire lung may be surgically removed. Nonsmokers typically fare better after surgery than smokers do.
- Chemotherapy. Powerful anticancer drugs are used to damage or destroy the cancer cells; however, chemotherapy also can damage surrounding healthy cells.
- Radiation therapy. High-intensity radiation directed toward the cancerous cells to destroy them or slow their growth.
- Immunotherapy. Drugs that help the immune system fight cancer.
- Targeted therapy. Anticancer drugs that can target specific types of genetic mutations that are driving lung cancer growth without damaging most surrounding healthy cells.
The five-year relative survival rate for people with NSCLC ranges from 63% for early-stage lung cancer that hasn’t spread beyond the lung to 7% for cancer that has spread to other parts of the body, such as the brain, bones, liver or other lung, according to the American Cancer Society.
“As we learn more about what causes these cancers, we’re learning more about their molecular biology,” Dr. Lee said. “We have already identified at least a half-dozen mutations and we have drugs for them. Lung cancer is becoming a more treatable illness. It’s a rapidly advancing field, and at RCCA we offer our patients the latest evidence-based therapies for lung cancer, as well as access to clinical trials.”
Protecting Your Respiratory Health
In addition to doing the obvious and not smoking, other steps to increase respiratory health include:
- Getting enough exercise. Physical Activity Guidelines for Americans recommends at least 150 to 300 minutes of aerobic activity each week. Activities such as bicycling or a brisk walk are perfect. Strength or resistance exercises such as pushups or weightlifting twice a week also are recommended.
- Maintain a healthy weight. Set a goal of having a body mass index (BMI) of between 18.5 and 24.9.
- Avoid secondhand smoke. Prohibit smoking of any kind, including cigarettes, pipes, cigars and vaping products, from a home or car, even with the windows open.
- Check the daily air quality index. Limit exercise if pollution levels are high, and stay away from high-traffic areas while exercising as a way to limit being exposed to diesel exhaust.
- Stay away from hazardous or lung-irritating substances. The Occupational Safety and Health Administration (OSHA) recommends wearing the proper protective respirator, such as an N-95 mask, when in contact with such substances in the workplace.
- Have homes tested for radon. To learn how, visit gov/radon or call the National Radon Hotline at 1-800-55RADON.
- Test well water annually. Consider having drinking water that comes from a private well tested for arsenic by a certified lab. This is especially critical for those who live in areas where arsenic is a concern. For more information about testing, visit gov/dwlabcert.
Drs. Horkheimer and Lee are among the more than 80 cancer specialists who treat patients at 20-plus RCCA care centers in New Jersey, Connecticut, Maryland and the Washington, D.C., area. These oncology specialists see more than 22,000 new patients each year and provide care to more than 225,000 established patients, collaborating closely with their patients’ other physicians. They offer patients the latest in cutting-edge treatments, including immunotherapies and targeted therapy, as well as access to a wide range of clinical trials. In addition to serving patients who have solid tumors, blood-based cancers and benign blood disorders such as anemia, RCCA care centers also provide infusion services to people with a number of non-oncologic conditions — including multiple sclerosis, Crohn’s disease, asthma and rheumatoid arthritis — who take intravenously-administered medications.
To learn more about RCCA, call 844-928-0089 or visit RCCA.com.
American Cancer Society. Lung cancer risks for non-smokers. https://www.cancer.org/latest-news/why-lung-cancer-strikes-nonsmokers.html. Accessed May 31, 2021.
American Cancer Society. Lung cancer survival rates: 5-year survival rates for lung cancer. https://www.cancer.org/cancer/lung-cancer/detection-diagnosis-staging/survival-rates.html. Accessed June 3, 2021.
American Lung Association. 10 tips to protect yourself from unhealthy air. https://www.lung.org/clean-air/outdoors/10-tips-to-protect-yourself. Accessed June 2, 2021.
American Lung Association. The State of the Air 2021: Key findings. https://www.lung.org/research/sota/key-findings. Accessed May 29, 2021.
Bhopal A, Peake MD, Gilligan D, Cosford P. Lung cancer in never-smokers: a hidden disease. J R Soc Med. 2019 Jul;112(7):269-271. doi: 10.1177/0141076819843654. Epub 2019 Apr 25.
Casal-Mourino A, Valdes L, Barros-Dios JM, Ruanno-Ravina A. Lung cancer survival among never smokers. Cancer Lett. 2019 Jun 1;451:142-149. doi: 10.1016/j.canlet.2019.02.047. Epub 2019 Mar 6.
Centers for Disease Control and Prevention. Arsenic and drinking water from private wells. https://www.cdc.gov/healthywater/drinking/private/wells/disease/arsenic.html. Accessed June 4, 2021.
Centers for Disease Control and Prevention. Assessing your weight. https://www.cdc.gov/healthyweight/assessing/index.html. Accessed June 2, 2021.
Centers for Disease Control and Prevention. Health effects of secondhand smoke. https://www.cdc.gov/tobacco/data_statistics/fact_sheets/secondhand_smoke/health_effects/index.htm. Accessed April 24, 2021.
Centers for Disease Control and Prevention. Lung cancer among people who never smoked. https://www.cdc.gov/cancer/lung/nonsmokers/index.htm. Accessed May 25, 2021.
Centers for Disease Control and Prevention. What are the risk factors for lung cancer? https://www.cdc.gov/cancer/lung/basic_info/risk_factors.htm. Accessed June 1, 2021.
Centers for Disease Control and Prevention. What are the symptoms of lung cancer? https://www.cdc.gov/cancer/lung/basic_info/symptoms.htm. Accessed May 31, 2021.
Centers for Disease Control and Prevention. Who should be screened for lung cancer? https://www.cdc.gov/cancer/lung/basic_info/screening.htm. Accessed June 1, 2021.
Dubin S, Griffin D. Lung cancer in non-smokers. Mo Med. Jul-Aug 2020;117(4):375-379.
Health.gov. Top 10 things to know about the second edition of the Physical Activity Guidelines for Americans. https://health.gov/our-work/physical-activity/current-guidelines/top-10-things-know. Accessed June 2, 2021.
National Cancer Institute. Secondhand smoke and cancer. https://www.cancer.gov/about-cancer/causes-prevention/risk/tobacco/second-hand-smoke-fact-sheet. Accessed April 24, 2021.
National Ground Water Association. Arsenic: What you need to know. https://www.ngwa.org/what-is-groundwater/Information-sheets. Accessed June 1, 2021.
Occupational Safety and Health Administration. Chemical hazards and toxic substances. https://www.osha.gov/chemical-hazards/controlling-exposure. Accessed June 4, 2021.
Pelosof L, Ahn C, Gao A, et al. Proportion of never-smoker non-small cell lung cancer patients at three diverse institutions. J Natl Cancer Inst. 2017 Jan 28;109(7):djw295. doi: 10.1093/jnci/djw295. Print 2017 Jan.
Smolle E, Pichler M. Non-smoking-associated lung cancer: A distinct entity in terms of tumor biology, patient characteristics and impact of hereditary cancer predisposition. Cancers. 2019 Feb 10;11(2):204.doi: 10.3390/cancers11020204.
UpToDate.com. Cigarette smoking and other possible risk factors for lung cancer. https://www.uptodate.com/contents/cigarette-smoking-and-other-possible-risk-factors-for-lung-cancer. Accessed April 28, 2021.
UpToDate.com. Lung cancer in never smokers. https://www.uptodate.com/contents/lung-cancer-in-never-smokers. Accessed April 28, 2021.
UpToDate.com. Vaping and e-cigarettes. https://www.uptodate.com/contents/vaping-and-e-cigarettes. Accessed April 28, 2021.
U.S. Environmental Protection Agency. Certification of Laboratories that Analyze Drinking Water Samples to Ensure Compliance with Regulations. https://www.epa.gov/dwlabcert. Accessed May 31. 2021.
Wakelee HA, Chang ET, Gomez SL, et al. Lung cancer incidence in never smokers. J Clin Oncol. 2007 Feb;25:472-478.
Yale Medicine. Lung cancer in nonsmokers. https://www.yalemedicine.org/conditions/lung-cancer-in-nonsmokers. Accessed April 28, 2021.